WO2022155843A1 - Adaptive anti-interference method and adaptive anti-interference device - Google Patents

Abstract

The present application discloses an adaptive anti-interference method and an adaptive anti-interference device. The method comprises: receiving a radio frequency signal; selecting a local oscillator frequency from a preset local oscillator frequency table as the frequency of a local oscillator signal; processing the local oscillator signal and the radio frequency signal to obtain an intermediate frequency signal; performing interference detection on the radio frequency signal and the intermediate frequency signal to obtain the signal strength of an interference signal, the interference signal comprising a barrage jamming signal and an adjacent channel interference signal; determining whether the signal strength of the interference signal meets a preset condition; if the signal strength of the interference signal does not meet the preset conditions, selecting another local oscillator frequency from the preset local oscillator frequency table as the frequency of the local oscillator signal, and returning to the step of processing the local oscillator signal and the received radio frequency signal to obtain an intermediate frequency signal until the signal strength of the interference signal meets the preset condition or all the local oscillator frequencies in the preset local oscillator frequency table are selected. In this way, the present application can improve the anti-interference ability.

Description

Adaptive anti-jamming method and adaptive anti-jamming device 【Technical field】

The present application relates to the field of communication technologies, and in particular, to an adaptive anti-jamming method and an adaptive anti-jamming device.

【Background technique】

The zero-IF receiver has the advantage of being highly integrated, and is more and more widely used in communication products, but the defects are also obvious. Due to the existence of the strong interference self-mixing phenomenon, the zero-IF anti-blocking ability is poor. Although the existing low-IF receiver scheme can effectively solve this kind of problem, it is at the expense of the adjacent channel anti-interference.

In the long-term research and development process, the inventor of the present application found that the current algorithm for interference detection is relatively complex, and will occupy a large amount of digital signal processor (DSP, Digital Signal Processor) resources. When the circuit has blocking interference and adjacent channel interference at the same time, the processing of the interference signal basically cannot achieve the anti-interference effect, which affects the useful signal.

[Content of the invention]

The main technical problem to be solved by this application is to provide an adaptive anti-jamming method and an adaptive anti-jamming device, which can improve the anti-jamming capability.

In order to solve the above-mentioned technical problems, a technical solution adopted in the present application is to provide an adaptive anti-jamming method, the method comprising: receiving a radio frequency signal; selecting a local oscillator frequency from a preset local oscillator frequency table as the frequency; process the local oscillator signal and the radio frequency signal to obtain the intermediate frequency signal; perform interference detection on the radio frequency signal and the intermediate frequency signal to obtain the signal strength of the interference signal, the interference signal includes the blocking interference signal and the adjacent channel interference signal; judge the signal strength of the interference signal Whether the preset conditions are met; if the signal strength of the interfering signal does not meet the preset conditions, select another LO frequency from the preset LO frequency table as the frequency of the LO signal, and return to perform a comparison between the LO signal and the received radio frequency. The step of processing the signal to obtain the intermediate frequency signal, until the signal strength of the interference signal satisfies the preset condition or all the local oscillator frequencies in the preset local oscillator frequency table have been selected.

In an implementation manner, the step of selecting a local oscillator frequency from the preset local oscillator frequency table as the frequency of the local oscillator signal includes: selecting the largest local oscillator frequency in the preset local oscillator frequency table as the frequency of the local oscillator signal.

In another implementation manner, the step of processing the local oscillator signal and the radio frequency signal to obtain the intermediate frequency signal includes: mixing the local oscillator signal and the radio frequency signal to generate the intermediate frequency signal.

In another implementation manner, the step of performing interference detection on the radio frequency signal and the intermediate frequency signal to obtain the signal strength of the interference signal includes: filtering the radio frequency signal to obtain a filtered radio frequency signal; blocking the interference on the filtered radio frequency signal Detect to obtain the signal strength of the blocking interference signal; perform adjacent channel interference detection on the intermediate frequency signal to obtain the signal strength of the adjacent channel interference signal.

In another implementation manner, the step of performing adjacent channel interference detection on the intermediate frequency signal to obtain the signal strength of the adjacent channel interference signal includes: performing analog-to-digital conversion on the intermediate frequency signal to obtain a digital signal; Interference detection, to obtain the signal strength of adjacent channel interference signals.

In another implementation manner, the method further includes processing the digital signal to generate a useful signal, and performing signal strength detection to obtain the signal strength of the useful signal.

In another implementation manner, the adjacent channel interference signal includes a left adjacent channel interference signal and a right adjacent channel interference signal, and the step of judging whether the signal strength of the interference signal satisfies a preset condition includes: judging the signal strength of the right adjacent channel interference signal and the Whether the difference between the signal strengths of the useful signals is greater than the right adjacent channel interference threshold; if the signal strength of the right adjacent channel interference signal is greater than the right adjacent channel interference threshold, use the signal strength of the left adjacent channel interference signal, the right adjacent channel interference signal Determine whether to adjust the frequency of the local oscillator signal; if the right adjacent channel interference signal is less than the right adjacent channel interference threshold, the frequency of the local oscillator signal will not be adjusted.

In another implementation manner, the step of judging whether to adjust the frequency of the local oscillator signal is based on the signal strength of the left adjacent channel interference signal, the signal strength of the right adjacent channel interference signal, the signal strength of the useful signal and the signal strength of the blocking interference signal Including: judging whether the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is greater than the left adjacent channel interference threshold; if the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is greater than the left adjacent channel interference threshold, calculate the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal, and use the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal, the left adjacent channel interference The signal strength of the signal and the signal strength of the right adjacent channel interference signal are used to determine whether to adjust the frequency of the local oscillator signal; if the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is less than or equal to the left adjacent channel interference Threshold, the frequency of the local oscillator signal will not be adjusted.

In another implementation manner, the preset LO frequency table includes multiple sets of LO frequencies, each set of LO frequencies includes a high LO frequency and a low LO frequency, and each set of LO frequencies and the blocking interference in the preset blocking suppression table The thresholds correspond to one-to-one, using the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal, the signal strength of the left adjacent channel interference signal and the signal strength of the right adjacent channel interference signal, to determine whether to adjust the frequency of the local oscillator signal The steps include: judging whether the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is greater than the next blocking interference threshold of the current blocking interference threshold; if the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal The difference between the two is greater than the next blocking interference threshold, then judge whether the signal strength of the interference signal of the right adjacent channel is greater than that of the interference signal of the left adjacent channel; if the signal strength of the interference signal of the right adjacent channel is greater than that of the interference signal of the left adjacent channel, Then adjust the frequency of the local oscillator signal to the low local oscillator frequency corresponding to the current blocking interference threshold; if the signal strength of the right adjacent channel interference signal is less than or equal to the signal strength of the left adjacent channel interference signal, then adjust the frequency of the local oscillator signal is the high local oscillator frequency corresponding to the current blocking interference threshold; if the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is less than or equal to the next blocking interference threshold, the next blocking interference threshold is used as the current blocking interference threshold , return to the step of judging whether the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is greater than the next blocking interference threshold of the current blocking interference threshold, until the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal The difference between them is less than or equal to the next blocking interference threshold, or the next blocking interference threshold is the last blocking interference threshold in the preset blocking interference threshold table.

In another implementation manner, the step of filtering the radio frequency signal to obtain the filtered radio frequency signal includes: performing low-pass filtering processing on the radio frequency signal to obtain the low-pass filtered radio frequency signal; The signal is subjected to band-pass filtering to obtain a filtered radio frequency signal.

In order to solve the above technical problem, another technical solution adopted in the present application is to provide an adaptive anti-jamming device, the adaptive anti-jamming device includes a processing circuit and a detection circuit, and the detection circuit is connected with the processing circuit. The processing circuit is used to receive the radio frequency signal; select a local oscillator frequency from the preset local oscillator frequency table as the frequency of the local oscillator signal; process the local oscillator signal and the radio frequency signal to obtain an intermediate frequency signal; the detection circuit is used to compare the radio frequency signal and the intermediate frequency The signal is subjected to interference detection to obtain the signal strength of the interference signal. The interference signal includes the blocking interference signal and the adjacent channel interference signal; the detection circuit is also used to determine whether the signal strength of the interference signal meets the preset condition; if the signal strength of the interference signal does not meet the predetermined condition If the condition is set, select another LO frequency from the preset LO frequency table as the frequency of the LO signal, and return to process the LO signal and the RF signal to obtain the intermediate frequency signal, until the signal strength of the interference signal meets the preset condition. Or all LO frequencies in the preset LO frequency table have been selected.

In one implementation, the processing circuit includes a radio frequency receiver, a low-pass filter and a band-pass filter; the radio frequency receiver is used for receiving radio frequency signals; the low-pass filter is connected to the radio frequency receiver, and is used for outputting the radio frequency receiver The radio frequency signal is filtered; the band pass filter is connected with the low pass filter, and is used for filtering the radio frequency signal output by the low pass filter.

In another implementation manner, the processing circuit further includes a local oscillator and a quadrature mixer: the local oscillator is used to generate the local oscillator signal; the quadrature mixer is connected to the local oscillator and used to combine the local oscillator signal with the local oscillator signal. The filtered RF signal output by the bandpass filter is mixed to generate an intermediate frequency signal.

In another implementation manner, the processing circuit further includes an analog-to-digital converter, and the analog-to-digital converter is configured to perform analog-to-digital conversion on the intermediate frequency signal to obtain a digital signal.

In another implementation manner, the adaptive anti-jamming device further includes a digital signal processor, which is connected to the processing circuit and the detection circuit, and is used for processing the digital signal to obtain a baseband signal.

In another implementation manner, the digital signal processor includes a channel filter and a demodulator; the channel filter is connected to an analog-to-digital converter, and is used for filtering the digital signal to obtain a filtered digital signal; the demodulator is connected to the analog-to-digital converter. The channel filter is connected to demodulate the filtered digital signal to generate a baseband signal.

In another implementation manner, the processing circuit further includes a controller, and the controller is connected to the detection circuit and the digital signal processor, and is used for controlling the detection circuit and the digital signal processor.

In another implementation, the detection circuit includes a blocking detector, an adjacent channel detector and a signal strength detector, the blocking detector is connected to the controller and the bandpass filter for detecting the signal strength of the blocking interference signal, and The signal strength of the blocking interference signal is input to the controller; the adjacent channel detector is connected with the controller and the analog-to-digital converter to detect the signal strength of the adjacent channel interference signal, and input the signal strength of the adjacent channel interference signal to the controller; The signal strength detector is connected with the controller and the channel filter for detecting the signal strength of the useful signal and inputting the signal strength of the useful signal to the controller.

In order to solve the above technical problem, another technical solution adopted in the present application is to provide a receiver, which includes interconnected antennas and the adaptive anti-jamming device in the above technical solution.

The beneficial effects of the present application are: different from the situation in the prior art, the present application can receive radio frequency signals; then select a local oscillator frequency from the preset local oscillator frequency table as the frequency of the local oscillator signal; and then combine the local oscillator signal and the radio frequency The signal is processed to obtain an intermediate frequency signal; then the blocking interference detection is performed on the radio frequency signal, and the adjacent channel interference detection is performed on the intermediate frequency signal; the signal strength of the blocking interference signal and the signal strength of the adjacent channel interference signal can be used to judge whether the current interference signal strength satisfies the forecast. Set conditions. If the preset conditions are not met, the frequency of the local oscillator signal needs to be adjusted to adjust the frequency of the intermediate frequency signal, and then it is determined whether the intensity of the interference signal corresponding to the newly generated intermediate frequency signal meets the preset conditions. If the preset conditions are met, continue to adjust the frequency of the local oscillator signal. If the preset conditions are met, end the adjustment process; because the higher the frequency of the intermediate frequency signal, the less obvious the signal self-mixing, and the stronger the ability to resist blocking interference. , but the greater the influence of adjacent channel interference, the worse the ability to resist adjacent channel interference. The application adjusts the frequency of the local oscillator signal, so that the frequency of the intermediate frequency signal changes, which can counteract adjacent channel interference and anti-blocking interference. , so that at a certain intermediate frequency, the signal strength of the blocking interference signal and the signal strength of the adjacent channel interference signal both meet the preset conditions, so that the ability to resist adjacent channel interference and the ability to resist blocking interference meet the requirements, which is helpful for Improve the anti-jamming capability of the receiver.

【Description of drawings】

1 is a schematic structural diagram of an embodiment of an adaptive anti-interference device provided by the present application;

2 is a schematic structural diagram of another embodiment of an adaptive anti-jamming device provided by the present application;

3 is a schematic flowchart of an embodiment of an adaptive anti-jamming method provided by the present application;

4 is a schematic flowchart of another embodiment of an adaptive anti-interference method provided by the present application;

FIG. 5 is a schematic flowchart of step 410 in the embodiment shown in FIG. 4;

6 is a schematic flowchart of step 53 in the embodiment shown in FIG. 5;

Fig. 7 is another schematic flow chart of step 53 in the embodiment shown in Fig. 5;

8 is a schematic diagram of an anti-jamming interruption test in an embodiment of an adaptive anti-jamming method provided by the present application;

FIG. 9 is a schematic structural diagram of an embodiment of a receiver provided by the present application.

【Detailed ways】

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

Please refer to FIG. 1 . FIG. 1 is a schematic structural diagram of an embodiment of an adaptive anti-jamming apparatus provided by the present application. The adaptive anti-jamming apparatus 10 includes a processing circuit 11 and a detection circuit 13 that are connected to each other.

The processing circuit 11 is used for receiving a radio frequency signal; selecting a local oscillator frequency from a preset local oscillator frequency table as the frequency of the local oscillator signal; and processing the local oscillator signal and the radio frequency signal to obtain an intermediate frequency signal.

The detection circuit 13 is used to perform interference detection on the radio frequency signal and the intermediate frequency signal to obtain the signal strength of the interference signal, and the interference signal includes the blocking interference signal and the adjacent channel interference signal.

The processing circuit 11 is also used to determine whether the signal strength of the interference signal satisfies the preset condition; if the signal strength of the interference signal does not meet the preset condition, another LO frequency is selected from the preset LO frequency table as the LO frequency of the LO signal. frequency, and return to process the local oscillator signal and the RF signal to obtain an intermediate frequency signal, until the signal strength of the interference signal meets the preset condition or all the local oscillator frequencies in the preset local oscillator frequency table have been selected.

Please refer to FIG. 2 . FIG. 2 is a schematic structural diagram of another embodiment of the adaptive anti-jamming apparatus provided by the present application. The adaptive anti-jamming apparatus 10 includes a processing circuit 11 and a detection circuit 13 .

The processing circuit 11 includes a radio frequency receiver 111 , a low-pass filter 112 , a band-pass filter 113 , a local oscillator 114 , a quadrature mixer 115 , an analog-to-digital converter 116 and a controller 117 .

The radio frequency receiver 111 is used to receive radio frequency signals; the low-pass filter 112 is connected to the radio frequency receiver 111, which is used to pass signals of useful frequencies in the received radio frequency signals, while suppressing signals of non-useful frequencies, that is, to set A desired frequency point allows signals lower than the desired frequency point to pass through, and signals higher than the desired frequency point are filtered out to eliminate part of the interference signal.

The band-pass filter 113 is connected to the low-pass filter 112, which is used to perform band-pass filtering on the signal output by the low-pass filter 112, that is, to set a certain frequency range, allow the signal falling within the frequency range to pass, and block the Or attenuate signals that fall outside this frequency range. Through the filtering action of the low-pass filter 112 and the band-pass filter 113, part of the interference signal can be eliminated.

The local oscillator 114 is used to generate a local oscillator signal, and select the maximum local oscillator frequency from the preset local oscillator frequency table as the frequency of the initial local oscillator signal; specifically, the processing circuit 11 stores a preset local oscillator frequency table, The preset local oscillator frequency table includes frequencies of multiple groups of local oscillator signals, and the frequencies of the local oscillator signals are arranged in descending order in the preset local oscillator frequency table. It can be understood that the preset LO frequency table can be set according to the application scenario in which the local oscillator 114 is located, and different application scenarios have different LO frequencies in the corresponding preset LO frequency table. In this embodiment, a low-IF receiver is used as an application scenario of the local oscillator 114, and the specific technical solution is described, but it is not limited to this.

The quadrature mixer 115 is connected to the local oscillator 114, and is used for mixing the local oscillator signal output by the local oscillator 114 and the filtered radio frequency signal output by the bandpass filter 113 to generate an intermediate frequency signal.

An analog-to-digital converter (ADC, Analog-to-Digital Converter) 116 is used to perform analog-to-digital conversion on the intermediate frequency signal generated by the quadrature mixer 115 to obtain a digital signal for digital processing.

Please continue to refer to FIG. 2 , the adaptive anti-jamming device 10 further includes a digital signal processor 15. The digital signal processor 15 is connected to the analog-to-digital converter 116 and the controller 117. The controller 117 can be used to control the local oscillator 114 and the detection circuit. 13 and digital signal processor 15.

The digital signal processor 15 includes a channel filter 151 and a demodulator 152; the channel filter 151 is used to filter the digital signal, so that the signal within a certain frequency range can pass completely, generate a useful digital signal, and filter out the signal outside a certain frequency range The demodulator 152 is used to restore the useful digital signal to the original signal, that is, the baseband signal, that is, the digital signal after analog-to-digital conversion can be filtered to generate a useful digital signal, and then generated by demodulation. baseband signal.

The detection circuit 13 includes a blockage detector 131 , an adjacent channel detector 132 and a signal strength detector 133 .

The blocking detector 131 is connected with the band-pass filter 113 and the controller 117, and is used for detecting the signal strength of the blocking interference signal; The radio frequency signal is subjected to blocking interference detection, thereby obtaining the signal strength of the blocking interference signal.

The adjacent channel detector 132 is connected with the controller 117, and is used for detecting the signal strength of the adjacent channel interference signal, the adjacent channel interference signal includes the left adjacent channel interference signal and the right adjacent channel interference signal; The digital signal is obtained by digital conversion, and the adjacent channel interference detection is performed on the channel where the digital signal is located, so as to obtain the signal strength of the left adjacent channel interference signal and the signal strength of the right adjacent channel interference signal.

The signal strength detector 133 is connected to the controller 117 and the channel filter 151, and is used to detect the signal strength of the useful signal; specifically, the signal strength detector 133 can perform signal strength detection on the filtered digital signal, thereby obtaining useful The signal strength of the signal.

This embodiment provides an adaptive anti-interference device, which includes a processing circuit, a detection circuit and a digital signal processor. The processing circuit mixes a radio frequency signal and a local oscillator signal to obtain an intermediate frequency signal, and modulates the intermediate frequency signal. The digital signal is obtained by digital conversion; the digital signal processor performs filtering processing on the digital signal obtained by analog-digital conversion; the detection circuit performs blocking interference detection, adjacent channel interference detection and useful signal detection. The RF signal is sampled, and the sampled RF signal is subjected to blocking interference detection to obtain the signal strength of the blocking interference signal; the adjacent channel detector is used to detect the adjacent channel interference on the channel where the digital signal generated after analog-to-digital conversion is located, and the right channel is obtained. The signal strength of the adjacent channel interference signal and the signal strength of the left adjacent channel interference signal; use the signal strength detector to detect the signal strength of the filtered digital signal to obtain the signal strength of the useful signal; by measuring the interference signal, the processing circuit It can judge whether the current LO frequency needs to be adjusted, so as to select the most suitable LO frequency to generate useful signals, which can make the mixed IF signal adapt to the situation of left and right adjacent channel interference and blocking interference at the same time, and obtain better bilateral Adjacent channel interference and blocking interference suppression effect, improve anti-interference ability.

Please refer to FIG. 1 and FIG. 3. FIG. 3 is a schematic flowchart of an embodiment of an adaptive anti-interference method provided by the present application. The method specifically includes the following steps:

Step 31: Receive a radio frequency signal.

The processing circuit 11 can receive the radio frequency signal, and filter the received radio frequency signal, so that the radio frequency signal within a certain frequency range can pass, and the radio frequency signal outside the certain frequency range can be blocked or attenuated, so as to eliminate or reduce the influence of the interference signal. .

In this implementation manner, in order to eliminate or reduce the influence of the interfering signal, the filtered signal may be used as the received radio frequency signal.

Step 32: Select a local oscillator frequency from the preset local oscillator frequency table as the frequency of the local oscillator signal.

The processing circuit 11 stores a preset local oscillator frequency table, the preset local oscillator frequency table includes multiple groups of local oscillator frequencies, each group of local oscillator frequencies includes a high local oscillator frequency and a low local oscillator frequency, and the high local oscillator frequency corresponds to the low local oscillator frequency. The frequency of the IF signal (IF frequency) is the same, the high LO frequency is the sum of the IF frequency and the RF signal frequency, and the low LO frequency is the difference between the RF signal and the IF frequency. The frequencies are listed in descending order. It can be understood that the preset LO frequency table can be set according to the application scenario where the processing circuit 11 is located, and the LO frequencies in the corresponding preset LO frequency table can be different for different application scenarios.

In this embodiment, the processing circuit 11 may select the maximum LO frequency in the preset LO frequency table from the preset LO frequency table as the frequency of the initial LO signal. The processing circuit 11 may select the local oscillator frequency switching in descending order from the preset local oscillator frequency table according to the interference situation of the application scene, and stop the frequency switching until a suitable local oscillator frequency is obtained.

Step 33: Process the local oscillator signal and the radio frequency signal to obtain an intermediate frequency signal.

The processing circuit 11 can perform mixing processing on the local oscillator signal and the filtered radio frequency signal to generate an intermediate frequency signal.

Step 34: Perform interference detection on the radio frequency signal and the intermediate frequency signal to obtain the signal strength of the interference signal.

The interference signal includes blocking interference signal and adjacent channel interference signal. The filtered radio frequency signal is sampled, and the sampling circuit 13 is used to perform blocking interference detection on the sampled radio frequency signal, so as to obtain the signal strength of the blocking interference signal, and the signal strength of the blocking interference signal can be obtained. The signal strength of the blocking interference signal is fed back to the processing circuit 11 ; in addition, the detection circuit 13 can also detect the signal strength of the adjacent channel interference signal and feed it back to the processing circuit 11 .

Step 35: Determine whether the signal strength of the interference signal satisfies the preset condition.

The processing circuit 11 can process the received signal strength of the blocking interference signal and the signal strength of the adjacent channel interference signal, that is, determine whether the signal strength of the interference signal satisfies a preset condition.

Step 36: If the signal strength of the interference signal does not meet the preset condition, select another LO frequency from the preset LO frequency table as the frequency of the LO signal.

If the signal strength of the interference signal does not meet the preset conditions, the frequency of the output local oscillator signal needs to be changed by the processing circuit 11, that is, the processing circuit 11 selects the next frequency of the current frequency from the preset local oscillator frequency table as the local oscillator the frequency of the signal, and return to step 33 until the signal strength of the interference signal satisfies the preset condition or all the LO frequencies in the preset LO frequency table have been selected. If the signal strength of the interference signal satisfies the preset condition, the processing circuit 11 does not adjust the frequency of the local oscillator signal.

In this embodiment, by detecting the signal strength of the interference signal at the current local oscillator frequency, it is judged whether to change the frequency of the output local oscillator signal, and then the size of the intermediate frequency signal is changed, so that the interference signal corresponding to the adjusted local oscillator frequency has a higher frequency. The signal strength meets the preset conditions. By adjusting the frequency of the local oscillator signal, the frequency of the intermediate frequency signal changes, so that the signal strength of the blocking interference signal and the signal strength of the adjacent channel interference signal both meet the preset conditions, which can improve when the adjacent channel interference and the blocking interference exist at the same time. anti-interference ability.

Please refer to FIG. 2 and FIG. 4. FIG. 4 is a schematic flowchart of another embodiment of an adaptive anti-jamming method provided by the present application. The adaptive anti-jamming method specifically includes the following steps:

Step 401: Receive a radio frequency signal.

The radio frequency receiver 111 can receive radio frequency signals, and input the received radio frequency signals into the low-pass filter 112 .

Step 402: Filter the radio frequency signal to obtain a filtered radio frequency signal.

In order to eliminate or reduce the influence of the interference signal, the filtered signal is used as the radio frequency signal mixed with the local oscillator signal; The low-pass filter 112 and the band-pass filter 113 can block or attenuate the passage of radio frequency signals outside a certain frequency range, so as to eliminate part of the interference signal.

Step 403: Perform blocking interference detection on the filtered radio frequency signal to obtain the signal strength of the blocking interference signal.

The blocking detector 131 can sample the filtered radio frequency signal, and then perform blocking interference detection on the sampled radio frequency signal to obtain the signal strength of the blocking interference signal, and can feed back the signal strength of the blocking interference signal to the controller 117 .

Step 404: Select the maximum LO frequency in the preset LO frequency table as the frequency of the LO signal.

A preset LO frequency table may be preset, and the preset LO frequency table includes multiple groups of LO frequencies, and the LO frequencies in the preset LO frequency table may be specifically set according to the application scenario where the local oscillator 114 is located. Further, the local oscillator 114 selects the maximum local oscillator frequency in the preset local oscillator frequency table as the frequency of the initial local oscillator signal, switches the frequency of the local oscillator 114, and stops frequency switching until a suitable local oscillator frequency is obtained.

Step 405: Mix the local oscillator signal with the radio frequency signal to generate an intermediate frequency signal.

The quadrature mixer 115 can perform mixing processing on the filtered radio frequency signal and the local oscillator signal output by the local oscillator 114 to generate an intermediate frequency signal.

Step 406: Perform analog-to-digital conversion on the intermediate frequency signal to obtain a digital signal, and perform adjacent channel interference detection on the channel where the digital signal is located to obtain the signal strength of the adjacent channel interference signal.

Use the analog-to-digital converter 116 to perform analog-to-digital conversion on the intermediate frequency signal to generate a corresponding digital signal, and then use the adjacent channel detector 132 to detect the channel where the digital signal obtained by the analog-to-digital conversion is located to obtain the signal of the adjacent channel interference signal The signal strength of the adjacent channel interference signal can be fed back to the controller 117; specifically, the adjacent channel interference signal includes a right adjacent channel interference signal and a left adjacent channel interference signal, and the left adjacent channel interference signal is a frequency lower than The signal of the frequency of the digital signal output by the analog-to-digital converter 116 , and the right adjacent channel interference signal is a signal with a frequency higher than the frequency of the digital signal output by the analog-to-digital converter 116 .

Step 407: Process the digital signal to generate a useful signal, and perform signal strength detection to obtain the signal strength of the useful signal.

In order to eliminate or reduce the interference caused by non-useful signals, the filtered digital signal can be used as the digital signal input to the signal strength detector 133 to obtain the signal strength of the useful signal; After the signal passes through the channel filter 151, the digital signal whose frequency falls within a certain frequency range passes, and the channel filter 151 can block or attenuate the passage of the digital signal outside the certain frequency range to eliminate part of the interference signal.

Step 408: Determine whether the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal is greater than the right adjacent channel interference threshold.

The right adjacent channel interference threshold can be preset, and the setting basis of the right adjacent channel interference threshold can include the signal strength of the maximum allowable right adjacent channel interference signal, the maximum allowable signal strength of the right adjacent channel interference signal and the signal strength ratio of the useful signal or the maximum allowable signal strength ratio. The difference between the signal strength of the right adjacent channel interfering signal and the signal strength of the wanted signal. The technical solution of this embodiment is described below by using the difference between the signal strength of the maximum allowable right adjacent channel interference signal and the signal strength of the useful signal as the right adjacent channel interference threshold, but it is not limited to this.

The controller 117 calculates the difference between the received signal strength of the interference signal in the right adjacent channel and the signal strength of the useful signal, and compares the difference between the signal strength of the interference signal in the right adjacent channel and the signal strength of the useful signal with the signal strength of the right adjacent channel. Compare with the channel interference threshold to determine whether to adjust the frequency of the local oscillator signal; if the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal is less than the right adjacent channel interference threshold, then go to step 409, otherwise go to step 409 410.

Step 409: If the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal is less than or equal to the right adjacent channel interference threshold, the frequency of the local oscillator signal is not adjusted.

If the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal is less than the right adjacent channel interference threshold, it indicates that the current right adjacent channel interference has little influence on the IF signal, and it is not necessary to adjust the frequency of the IF signal at this time. Keep the LO frequency as the high LO frequency of the current group of LO frequencies.

Step 410: If the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal is greater than the right adjacent channel interference threshold, use the signal strength of the left adjacent channel interference signal, the signal strength of the right adjacent channel interference signal, The signal strength of the useful signal and the signal strength of the blocking interference signal are used to determine whether to adjust the frequency of the local oscillator signal.

If the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal is greater than the right adjacent channel interference threshold, it indicates that the current right adjacent channel interference has a great influence on the IF signal, which exceeds the current maximum allowable limit. Use the signal strength of the interference signal of the right adjacent channel, the signal strength of the interference signal of the left adjacent channel, the signal strength of the useful signal and the signal strength of the blocking interference signal to judge whether the IF frequency needs to be adjusted, that is, it is necessary to combine the interference situation and blocking of the left adjacent channel. The interference situation comprehensively judges whether it is necessary to adjust the frequency of the local oscillator signal.

In a specific embodiment, the solution shown in FIG. 5 can be used for processing to determine whether the frequency of the local oscillator signal needs to be adjusted, which specifically includes the following steps:

Step 51: Determine whether the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is greater than the left adjacent channel interference threshold.

The left adjacent channel interference threshold can be preset, and the setting basis of the left adjacent channel interference threshold can include the signal strength of the maximum allowable left adjacent channel interference signal, the ratio of the maximum allowable left adjacent channel interference signal signal strength and the signal strength of the useful signal, or the ratio of the signal strength of the maximum allowable left adjacent channel interference signal to the signal strength of the useful signal. The maximum allowable difference between the signal strength of the left adjacent channel interfering signal and the signal strength of the wanted signal. The technical solution of this embodiment is described below by using the difference between the signal strength of the maximum allowable left adjacent channel interference signal and the signal strength of the useful signal as the left adjacent channel interference threshold, but it is not limited thereto.

The controller 117 calculates the difference between the received signal strength of the left adjacent channel interference signal and the signal strength of the useful signal, and calculates the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal and the left adjacent channel interference. The thresholds are compared to determine whether to adjust the frequency of the local oscillator signal; if the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is less than or equal to the left adjacent channel interference threshold, step 52 is performed, otherwise, step 52 is performed. 53.

Step 52: If the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is less than or equal to the left adjacent channel interference threshold, the frequency of the local oscillator signal is not adjusted.

If the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is less than the left adjacent channel interference threshold, it indicates that the current left adjacent channel interference has little influence on the IF signal, and it is not necessary to adjust the frequency of the IF signal at this time. , set the LO frequency to the lower LO frequency under the current group of LO frequencies in the preset LO frequency table.

Step 53: If the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is greater than the left adjacent channel interference threshold, calculate the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal, Use the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal, the signal strength of the right adjacent channel interference signal and the signal strength of the left adjacent channel interference signal to determine whether to adjust the frequency of the local oscillator signal.

If the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is greater than the left adjacent channel interference threshold, it indicates that the current left adjacent channel interference has a great influence on the IF signal, which exceeds the current maximum allowable limit. Use the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal, the signal strength of the right adjacent channel interference signal and the signal strength of the left adjacent channel interference signal to determine whether the frequency of the local oscillator signal needs to be adjusted, that is, the need to adjust the frequency of the local oscillator signal. Combined with the blocking interference, the signal strength of the useful signal, and the interference of the left adjacent channel and the right adjacent channel, it is comprehensively judged whether the frequency of the local oscillator signal needs to be adjusted.

Further, a preset blocking interference threshold table can be preset, and the blocking interference threshold in the preset blocking interference threshold table is in one-to-one correspondence with each group of local oscillator frequencies in the preset local oscillator frequency table, and the blocking interference threshold can be set to a maximum value. The difference between the signal strength of the blocking interfering signal and the signal strength of the wanted signal is allowed. In this embodiment, the low-IF receiver is used as the application scenario of the local oscillator 114 to set the preset local oscillator frequency table, and the blocking interference threshold table measured and set according to the preset local oscillator frequency table is used to describe the technical solution of this embodiment. But not limited to this.

The controller 117 is used to calculate the difference between the received signal strength of the blocking interference signal and the signal strength of the useful signal to obtain the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal, and use the blocking interference signal The difference between the signal strength of the desired signal and the signal strength of the useful signal, the signal strength of the right adjacent channel interference signal and the signal strength of the left adjacent channel interference signal determine whether the frequency of the local oscillator signal needs to be adjusted.

In a specific embodiment, the solution shown in FIG. 6 can be used for processing to determine whether the frequency of the local oscillator signal needs to be adjusted, which specifically includes the following steps:

Step 61: Determine whether the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is greater than the next blocking interference threshold of the current blocking interference threshold.

The difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is recorded as blocking interference; the frequency of the current local oscillator signal can be obtained, that is, it is assumed that it is currently in the nth group of local oscillator frequencies in the preset local oscillator frequency table; And obtain the n+1th blocking interference threshold in the preset blocking interference threshold table, and then judge whether the blocking interference corresponding to the nth group of local oscillator frequencies is greater than the n+1th blocking interference threshold.

If the difference between the signal strength of the current blocking interference signal and the signal strength of the useful signal is greater than the next blocking interference threshold of the current blocking interference threshold, step 62 is performed; otherwise, step 65 is performed.

Step 62: If the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is greater than the next blocking interference threshold, determine whether the signal strength of the right adjacent channel interference signal is greater than that of the left adjacent channel interference signal.

If the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is greater than the next blocking interference threshold of the current blocking interference threshold, it indicates that the current frequency has good anti-blocking interference ability, and it has better anti-blocking interference ability at the current frequency. Under the interference ability, the ability to detect the anti-adjacent channel interference can balance the anti-adjacent channel interference ability and the anti-blocking interference ability, and obtain the optimal bilateral adjacent channel interference suppression effect.

If the signal strength of the right adjacent channel interference signal is greater than the signal strength of the left adjacent channel interference signal, step 63 is performed; otherwise, step 64 is performed.

Step 63: If the signal strength of the right adjacent channel interference signal is greater than the signal strength of the left adjacent channel interference signal, adjust the frequency of the local oscillator signal to a low local oscillator frequency corresponding to the current blocking interference threshold.

If the signal strength of the interference signal of the right adjacent channel is greater than the signal strength of the interference signal of the left adjacent channel, it indicates that the interference received by the left adjacent channel is relatively small. At this time, the controller 117 can control the local oscillator 114 to adjust the local oscillator frequency so as to make the local oscillator The frequency of the signal is adjusted to a low local oscillator frequency corresponding to the current blocking interference threshold.

Step 64: If the signal strength of the right adjacent channel interference signal is less than or equal to the signal strength of the left adjacent channel interference signal, adjust the frequency of the local oscillator signal to a high local oscillator frequency corresponding to the current blocking interference threshold.

If the signal strength of the interference signal of the right adjacent channel is less than or equal to the signal strength of the interference signal of the left adjacent channel, it indicates that the interference received by the right adjacent channel is relatively small. At this time, the controller 117 can control the local oscillator 114 to adjust the local oscillator frequency to The frequency of the local oscillator signal is adjusted to a high local oscillator frequency corresponding to the current blocking interference threshold.

Step 65: If the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is less than or equal to the next blocking interference threshold, the next blocking interference threshold is used as the current blocking interference threshold.

When the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is less than or equal to the next blocking interference threshold, take the next blocking interference threshold as the current blocking interference threshold, and return to execute the judgment of the signal strength of the blocking interference signal Whether the difference with the signal strength of the useful signal is greater than the next blocking interference threshold of the current blocking interference threshold, that is, step 61 is performed until the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is less than or equal to The next blocking interference threshold, or the next blocking interference threshold is the last blocking interference threshold in the preset blocking interference threshold table.

When the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is less than or equal to the next blocking interference threshold of the current blocking interference threshold, it indicates that the anti-blocking interference capability at the current IF frequency does not meet the conditions, and it does not have a better performance. Anti-blocking interference capability. At this time, a new IF frequency can be obtained by adjusting the frequency of the local oscillator signal, so that it has better anti-blocking interference capability.

For example, currently in the nth group of local oscillator frequencies in the preset local oscillator frequency table, and the blocking interference threshold corresponding to the nth group of local oscillator frequencies, set n=n+1, and set the frequency of the n+1th group of local oscillator signals As the current frequency of the local oscillator signal, and use the blocking interference threshold corresponding to the n+1th group of local oscillator frequencies as the current blocking interference threshold, continue to judge the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal Whether it is greater than the next blocking interference threshold until the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal meets the preset condition or the next blocking interference threshold is the last blocking interference in the preset blocking interference threshold table When the threshold is reached, stop adjusting.

In another embodiment, as shown in Figure 7, an adjacent channel interference threshold can also be added to determine whether the frequency of the local oscillator signal needs to be adjusted, which specifically includes the following steps:

Step 71: Determine whether the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is greater than the next blocking interference threshold of the current blocking interference threshold.

Step 71 is similar to step 61 in the foregoing embodiment, and details are not described herein again.

If the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is greater than the next blocking interference threshold, step 72 is performed; otherwise, step 79 is performed.

Step 72: If the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is greater than the next blocking interference threshold, determine the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal and Whether the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is both smaller than the adjacent channel interference threshold.

When the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is greater than the next blocking interference threshold of the current blocking interference threshold, it indicates that the current frequency has better anti-blocking interference ability, and has better anti-blocking interference ability at the current frequency. Under the interference ability, the ability to detect the anti-adjacent channel interference can balance the anti-adjacent channel interference and the anti-blocking interference, and obtain the optimal bilateral adjacent channel interference suppression effect.

The adjacent channel interference threshold represents the difference between the maximum allowable adjacent channel interference signal strength and the useful signal strength. A preset adjacent channel interference threshold table can be preset. The adjacent channel interference threshold in the preset adjacent channel interference threshold table is the same as the preset local oscillator Each group of LO frequencies in the frequency table corresponds to each other. In this embodiment, the low-IF receiver is used as the application scenario of the local oscillator 114 to set the preset local oscillator frequency table, and the preset adjacent channel interference threshold table measured and set according to the preset local oscillator frequency table will affect the technology of this embodiment. scenarios are described, but not limited to this.

Obtain the frequency of the current local oscillator signal, that is, assuming that it is currently in the nth group of local oscillator frequencies in the preset local oscillator frequency table, and obtain the nth adjacent channel interference threshold in the preset adjacent channel interference threshold table, and then determine the left adjacent channel. Whether the difference between the signal strength of the interference signal and the signal strength of the useful signal and the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal are both smaller than the nth adjacent channel interference threshold.

If the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal and the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal are both smaller than the adjacent channel interference threshold, step 75 is performed. If the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal or the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is not less than the adjacent channel interference threshold, it can be judged that the right adjacent channel interference Whether the difference between the signal strength of the signal and the signal strength of the useful signal is not less than the adjacent channel interference threshold and whether the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is less than the adjacent channel interference threshold.

If the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal is greater than or equal to the adjacent channel interference threshold and the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is less than the adjacent channel interference threshold, then Perform step 73; if the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal is less than the adjacent channel interference threshold or the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is not less than the adjacent channel interference threshold, then judge whether the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal is not less than the adjacent channel interference threshold and whether the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is not less than the adjacent channel interference threshold. channel interference threshold.

If the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal is less than the adjacent channel interference threshold and the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is greater than or equal to the adjacent channel interference threshold, then Step 74 is performed; if the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal and the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal are all greater than or equal to the adjacent channel interference threshold, then Go to step 78.

Step 73: If the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal is greater than or equal to the adjacent channel interference threshold and the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal If it is less than the adjacent channel interference threshold, the frequency of the local oscillator signal is adjusted to the low local oscillator frequency corresponding to the current adjacent channel interference threshold.

If the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal is greater than or equal to the adjacent channel interference threshold, and the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is less than the adjacent channel interference threshold, It shows that at the current IF frequency, the interference of the right adjacent channel has a greater impact on the IF signal, which exceeds the limit of the current channel to suppress the interference of the adjacent channel, while the interference of the left adjacent channel has a small impact on the IF signal, and there is no need to adjust the IF signal at this time. The local oscillator 114 is controlled by the controller 117 to adjust the local oscillator frequency, and the frequency of the local oscillator signal is adjusted to a low local oscillator frequency corresponding to the current adjacent channel interference threshold.

Step 74: If the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal is less than the adjacent channel interference threshold and the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is greater than or equal to the adjacent channel interference threshold, then adjust the frequency of the local oscillator signal to the high local oscillator frequency corresponding to the current adjacent channel interference threshold.

If the difference between the signal strength of the right adjacent channel interfering signal and the signal strength of the wanted signal is less than the adjacent channel interference threshold, and the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the wanted signal is greater than or equal to the adjacent channel interference threshold, It shows that at the current IF frequency, the interference of the left adjacent channel has a greater impact on the IF signal, which exceeds the limit of the current channel to suppress the interference signal, while the interference of the right adjacent channel has a small impact on the IF signal, so there is no need to adjust the IF signal at this time. The local oscillator 114 is controlled by the controller 117 to adjust the local oscillator frequency, and the frequency of the local oscillator signal is adjusted to a high local oscillator frequency corresponding to the current adjacent channel interference threshold.

Step 75: If the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal and the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal are both less than the adjacent channel interference threshold, Then it is judged whether the signal strength of the interference signal of the right adjacent channel is greater than that of the interference signal of the left adjacent channel.

If the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal and the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal are both smaller than the adjacent channel interference threshold, it means that at the current IF frequency, The influence of the left adjacent channel interference signal and the right adjacent channel interference signal on the IF signal is relatively small. At this time, the controller 117 can compare the received left adjacent channel interference signal with the right adjacent channel interference signal, and select the adjacent channel interference signal strength. smaller for better adjacent channel interference suppression.

If the signal strength of the interference signal of the right adjacent channel is greater than the signal strength of the interference signal of the left adjacent channel, step 76 is performed; otherwise, step 77 is performed.

Step 76: If the signal strength of the right adjacent channel interference signal is greater than the signal strength of the left adjacent channel interference signal, adjust the frequency of the local oscillator signal to a low local oscillator frequency corresponding to the current adjacent channel interference threshold.

If the signal strength of the interference signal of the right adjacent channel is greater than the signal strength of the interference signal of the left adjacent channel, it indicates that the interference received by the left adjacent channel is relatively small. At this time, the controller 117 can control the local oscillator 114 to adjust the local oscillator frequency so as to make the local oscillator The frequency of the signal is adjusted to a low local oscillator frequency corresponding to the current adjacent channel interference threshold.

Step 77: If the signal strength of the right adjacent channel interference signal is less than or equal to the signal strength of the left adjacent channel interference signal, adjust the frequency of the local oscillator signal to a high local oscillator frequency corresponding to the current adjacent channel interference threshold.

If the signal strength of the interference signal of the right adjacent channel is less than or equal to the signal strength of the interference signal of the left adjacent channel, it indicates that the interference received by the right adjacent channel is relatively small. At this time, the controller 117 can control the local oscillator 114 to adjust the local oscillator frequency to The frequency of the local oscillator signal is adjusted to a high local oscillator frequency corresponding to the current adjacent channel interference threshold.

Step 78: If the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal and the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal are both greater than or equal to the adjacent channel interference threshold, the next adjacent channel interference threshold is used as the current adjacent channel interference threshold.

When the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal and the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal are both greater than or equal to the current adjacent channel interference threshold, the next The adjacent channel interference threshold is used as the current adjacent channel interference threshold, and returns to perform step 72 until the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal and/or the signal strength of the left adjacent channel interference signal and the useful signal. The difference between the signal strengths is smaller than the adjacent channel interference threshold, or the current adjacent channel interference threshold is the last adjacent channel suppression degree in the preset adjacent channel interference threshold table.

If the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the wanted signal and the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the wanted signal are both greater than or equal to the adjacent channel interference threshold, it indicates that the current IF frequency The influence of the right adjacent channel interference and the left adjacent channel interference on the IF signal exceeds the maximum suppression limit of the current channel to the interference signal. A new IF frequency can be obtained by adjusting the frequency of the local oscillator signal, so that it has better anti-adjacent channel interference capability.

For example, currently in the nth group of local oscillator frequencies in the preset local oscillator frequency table, and the adjacent channel interference threshold corresponding to the nth group of local oscillator frequencies, set n=n+1, and the n+1th group of local oscillator signals The frequency is used as the frequency of the current local oscillator signal, and the adjacent channel interference threshold corresponding to the n+1 groups of local oscillator frequencies is used as the current adjacent channel interference threshold, and returns to step 72 until the signal strength of the right adjacent channel interference signal and the signal of the useful signal The difference in strength and/or the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is less than the adjacent channel interference threshold, or the current adjacent channel interference threshold is the last adjacent channel interference in the preset adjacent channel interference threshold table. threshold, stop adjusting.

Step 79: If the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is less than or equal to the next blocking interference threshold, the next blocking interference threshold is used as the current blocking interference threshold.

Step 79 is similar to step 65 in the above-mentioned embodiment, and is not repeated here.

Please refer to FIG. 9 . FIG. 9 is a schematic structural diagram of an embodiment of a receiver provided by the present application. The receiver 20 includes an antenna 21 and an adaptive anti-jamming device 10 that are connected to each other.

The antenna 21 is used to receive radio frequency signals.

The adaptive anti-jamming device 10 includes a processing circuit 11 and a detection circuit 13 which are connected to each other.

The processing circuit 11 is used for receiving a radio frequency signal; selecting a local oscillator frequency from a preset local oscillator frequency table as the frequency of the local oscillator signal; and processing the local oscillator signal and the radio frequency signal to obtain an intermediate frequency signal.

The detection circuit 13 is configured to perform interference detection on the radio frequency signal and the intermediate frequency signal to obtain the signal strength of the interference signal, wherein the interference signal includes a blocking interference signal and an adjacent channel interference signal.

Further, the processing circuit 11 is also used to judge whether the signal strength of the interference signal satisfies the preset condition; if not, select another LO frequency from the preset LO frequency table as the frequency of the LO signal, and return to execute the LO frequency. The signal and the radio frequency signal are processed to obtain the intermediate frequency signal, until the signal strength of the interference signal meets the preset condition or all the local oscillator frequencies in the preset local oscillator frequency table have been selected.

The implementation process and effect of the adaptive anti-jamming method in this embodiment are described below with an example.

Example 1:

Table 1 Preset Interference Threshold Table

group IF frequency/KHz Blocking Interference Threshold/dB Adjacent channel interference threshold/dB 1 4.5 100 45 2 3.6 94 56 3 2.5 80 70 4 1.5 70 71 5 0.3 60 71

As shown in Table 1, the third column corresponds to the interference rejection threshold at the current intermediate frequency, and the fourth column corresponds to the adjacent channel interference threshold at the current intermediate frequency. With the decrease of the intermediate frequency, the blocking interference threshold decreases, and the blocking interference threshold increases, that is, the anti-blocking interference capability is reduced, and the anti-adjacent channel interference capability is improved. Because the higher the intermediate frequency, the stronger the ability to resist blocking interference, but the less ability to resist adjacent channel interference. The ability of channel interference and anti-blocking interference meet the requirements, and it can have anti-interference ability in the complex environment where dual-adjacent channel interference and blocking interference coexist; understandably, the data in Table 1 is only an example, and the specific values can be Adjust according to actual application needs.

Example 2:

Table 2 The test results of the walkie-talkie using the low-IF receiver

Among them, L, M, H are three different channels, the channel interval is 12.5KHz, L is the low frequency channel, M is the intermediate frequency channel, and H is the high frequency channel; L, M, and H, respectively use the method of this embodiment and the existing method to test the reference sensitivity, the anti-blocking interference ability, and the anti-adjacent channel interference ability.

It can be seen from Table 2 that whether or not the adaptive anti-jamming method of this embodiment is used has basically no effect on the reference sensitivity and anti-blocking interference ability of the walkie-talkie, but the anti-jamming method of this embodiment has a significant anti-jamming ability against adjacent channel interference. Influence, when using the existing method, the anti-adjacent channel interference capability is less than 45dB, and after using the method of this embodiment, the anti-adjacent channel interference capability reaches 70dB, which significantly improves the anti-adjacent channel interference capability.

Example 3

Please refer to FIG. 8 and Table 3. FIG. 8 is a schematic diagram of an anti-jamming interruption test in an embodiment of an adaptive anti-jamming method provided by the present application. An interference source 81 is used to generate an interference signal to test the receiver 20 , assuming a channel The frequency (F1) is 436.625MHz, the frequency of the blocking interference signal is F1+10MHz, the frequency of the right adjacent channel interference signal is F1+12.5kHz, and the frequency of the left adjacent channel interference signal is F1-12.5kHz, as shown in Table 3. 's test results.

Table 3 Anti-interference interruption test results

The digital channel may be a digital mobile radio channel (DMR, Digital Mobile Radio).

The radiation test is based on the distance between the specific position where the useful signal disappears in the channel (that is, the signal strength of the useful signal is 0) and the receiver 20 due to interference during the signal transmission process as the judgment criterion; For the device using the anti-jamming method of this embodiment, the distance from the position where the useful signal disappears from the receiver 20 is greater than 10m, and after using the anti-jamming method in this embodiment, the distance from the position where the useful signal disappears from the receiver 20 is 1m From left to right, the distance is significantly shortened, so the anti-interference adaptive method of this embodiment is used to significantly improve the anti-interference ability.

The conduction test is based on the signal strength of the useful signal at the same position during the signal transmission process as the criterion; it can be seen from Table 3 that for the equipment that does not use the anti-jamming method of this embodiment, the signal strength of the useful signal at a certain position is 35dB However, after using the anti-jamming method of this embodiment, the signal strength of a useful signal at the same position is about 65dB, so using the anti-jamming method of this embodiment can reduce the influence of the interference source 81 on signal transmission.

According to the test data, in a complex environment such as single/dual adjacent channel interference or single/dual adjacent channel plus blocking interference, the use of the anti-jamming adaptive method of this embodiment can shorten the distance between the disappearance position of the signal and the receiver 20, and The influence of the interference source 81 on signal transmission can be reduced, so that the signal strength at the same position is increased compared to the existing method, thereby improving the anti-interference ability.

The solution of this embodiment determines whether the frequency of the local oscillator signal needs to be adjusted according to the signal strength of the blocking interference signal, the signal strength of the adjacent channel interference signal, and the signal strength of the useful signal. By adjusting the frequency of the local oscillator signal, the intermediate frequency signal If the frequency of the device changes, it can equalize against adjacent channel interference and anti-blocking interference, so that at a certain intermediate frequency, the ability to resist adjacent channel interference and anti-blocking interference meets the requirements, which helps to improve the anti-interference ability.

The above description is only an embodiment of the present application, and is not intended to limit the scope of the patent of the present application. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present application, or directly or indirectly applied to other related technologies Fields are similarly included within the scope of patent protection of this application.

Claims (19)

An adaptive anti-interference method, characterized in that the method comprises: receive radio frequency signals; Select a LO frequency from the preset LO frequency table as the frequency of the LO signal; processing the local oscillator signal and the radio frequency signal to obtain an intermediate frequency signal; Perform interference detection on the radio frequency signal and the intermediate frequency signal to obtain the signal strength of the interference signal, wherein the interference signal includes a blocking interference signal and an adjacent channel interference signal; judging whether the signal strength of the interference signal satisfies a preset condition; If not, select another LO frequency from the preset LO frequency table as the frequency of the LO signal, and return to performing the processing of the LO signal and the RF signal to obtain an intermediate frequency signal until the signal strength of the interference signal satisfies the preset condition or all the LO frequencies in the preset LO frequency table have been selected. The adaptive anti-interference method according to claim 1, wherein the step of selecting a local oscillator frequency from a preset local oscillator frequency table as the frequency of the local oscillator signal comprises: The maximum local oscillator frequency in the preset local oscillator frequency table is selected as the frequency of the local oscillator signal. The adaptive anti-jamming method according to claim 1, wherein the step of processing the local oscillator signal and the radio frequency signal to obtain an intermediate frequency signal comprises: Mixing the local oscillator signal and the radio frequency signal to generate the intermediate frequency signal. The adaptive anti-interference method according to claim 1, wherein the step of performing interference detection on the radio frequency signal and the intermediate frequency signal to obtain the signal strength of the interference signal comprises: Filtering the radio frequency signal to obtain a filtered radio frequency signal; performing blocking interference detection on the filtered radio frequency signal to obtain the signal strength of the blocking interference signal; Performing adjacent channel interference detection on the intermediate frequency signal to obtain the signal strength of the adjacent channel interference signal. The adaptive anti-interference method according to claim 4, wherein the step of performing adjacent channel interference detection on the intermediate frequency signal to obtain the signal strength of the adjacent channel interference signal comprises: performing analog-to-digital conversion on the intermediate frequency signal to obtain a digital signal; Perform adjacent channel interference detection on the channel where the digital signal is located to obtain the signal strength of the adjacent channel interference signal. The adaptive anti-jamming method according to claim 5, wherein the method further comprises: The digital signal is processed to generate a useful signal, and signal strength is detected to obtain the signal strength of the useful signal. The adaptive anti-jamming method according to claim 1, wherein the adjacent channel interference signal includes a left adjacent channel interference signal and a right adjacent channel interference signal, and the judging whether the signal strength of the interference signal satisfies a preset Conditional steps, including: Determine whether the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal is greater than the right adjacent channel interference threshold; If yes, use the signal strength of the left adjacent channel interference signal, the signal strength of the right adjacent channel interference signal, the signal strength of the useful signal and the signal strength of the blocking interference signal to determine whether to adjust the local oscillator the frequency of the signal; If not, the frequency of the local oscillator signal is not adjusted. The adaptive anti-interference method according to claim 7, wherein the signal strength of the left adjacent channel interference signal, the signal strength of the right adjacent channel interference signal, the signal strength of the useful signal, and the The signal strength of the blocking interference signal, and the step of judging whether to adjust the frequency of the local oscillator signal includes: Judging whether the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is greater than the left adjacent channel interference threshold; If the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is greater than the left adjacent channel interference threshold, calculate the signal strength of the blocking interference signal and the signal strength of the useful signal The difference between the strengths, using the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal, the signal strength of the left adjacent channel interference signal, and the signal strength of the right adjacent channel interference signal strength, to determine whether to adjust the frequency of the local oscillator signal; If the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal is less than or equal to the left adjacent channel interference threshold, the frequency of the local oscillator signal is not adjusted. The adaptive anti-interference method according to claim 8, wherein the preset local oscillator frequency table includes a plurality of groups of local oscillator frequencies, each group of the local oscillator frequencies includes a high local oscillator frequency and a low local oscillator frequency, and each group of the The local oscillator frequency has a one-to-one correspondence with the blocking interference threshold in the preset blocking interference threshold table, and the use of the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal, the left adjacent channel interference The signal strength of the signal and the signal strength of the right adjacent channel interference signal, and the step of judging whether to adjust the frequency of the local oscillator signal includes: Judging whether the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is greater than the next blocking interference threshold of the current blocking interference threshold; If the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is greater than the next blocking interference threshold, determine whether the signal strength of the right adjacent channel interference signal is greater than the left adjacent channel the signal strength of the interfering signal; If the signal strength of the right adjacent channel interference signal is greater than the signal strength of the left adjacent channel interference signal, adjusting the frequency of the local oscillator signal to the low local oscillator frequency corresponding to the current blocking interference threshold; If the signal strength of the right adjacent channel interference signal is less than or equal to the signal strength of the left adjacent channel interference signal, adjusting the frequency of the local oscillator signal to the high local oscillator frequency corresponding to the current blocking interference threshold; If the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is less than or equal to the next blocking interference threshold, the next blocking interference threshold is used as the current blocking interference threshold, Return to the step of judging whether the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is greater than the next blocking interference threshold of the current blocking interference threshold, until the signal strength of the blocking interference signal The difference from the signal strength of the useful signal is less than or equal to the next blocking interference threshold, or the next blocking interference threshold is the last blocking interference threshold in the preset blocking interference threshold table. The adaptive anti-interference method according to claim 4, wherein the step of filtering the radio frequency signal to obtain the filtered radio frequency signal comprises: performing low-pass filtering on the radio frequency signal to obtain a low-pass filtered radio frequency signal; Band-pass filtering is performed on the low-pass filtered radio frequency signal to obtain the filtered radio frequency signal. An adaptive anti-jamming device, comprising: a processing circuit, which is used to receive radio frequency signals; select a local oscillator frequency from a preset local oscillator frequency table as the frequency of the local oscillator signal; process the local oscillator signal and the radio frequency signal to obtain an intermediate frequency signal ; a detection circuit, connected to the processing circuit, for performing interference detection on the radio frequency signal and the intermediate frequency signal to obtain the signal strength of the interference signal, wherein the interference signal includes a blocking interference signal and an adjacent channel interference signal; Wherein, the processing circuit is further configured to judge whether the signal strength of the interference signal satisfies a preset condition; if not, select another LO frequency from the preset LO frequency table as the LO frequency of the LO signal frequency, return to process the local oscillator signal and the radio frequency signal to obtain an intermediate frequency signal, until the signal strength of the interference signal satisfies the preset condition or all the local oscillators in the preset local oscillator frequency table The frequencies have been selected. The adaptive anti-jamming device according to claim 11, wherein the processing circuit comprises: a radio frequency receiver for receiving the radio frequency signal; a low-pass filter, connected to the radio frequency receiver, for filtering the radio frequency signal output by the radio frequency receiver; A band-pass filter, connected to the low-pass filter, is used for filtering the radio frequency signal output by the low-pass filter. The adaptive anti-jamming device according to claim 12, wherein the processing circuit further comprises: a local oscillator for generating the local oscillator signal; A quadrature mixer, connected to the local oscillator, is configured to mix the local oscillator signal with the filtered radio frequency signal output by the bandpass filter to generate the intermediate frequency signal. The adaptive anti-jamming device according to claim 12, wherein: The processing circuit further includes an analog-to-digital converter configured to perform analog-to-digital conversion on the intermediate frequency signal to obtain a digital signal. The adaptive anti-jamming device according to claim 14, wherein: The adaptive anti-interference device further includes a digital signal processor, which is connected to the processing circuit and the detection circuit, and is used for processing the digital signal to obtain a baseband signal. The adaptive anti-jamming device according to claim 15, wherein the digital signal processor comprises: a channel filter, connected to the analog-to-digital converter, for filtering the digital signal to obtain a filtered digital signal; A demodulator, connected to the channel filter, is configured to demodulate the filtered digital signal to generate the baseband signal. The adaptive anti-jamming device according to claim 16, wherein: The processing circuit further includes a controller connected to the detection circuit and the digital signal processor for controlling the detection circuit and the digital signal processor. The adaptive anti-jamming device according to claim 17, wherein the detection circuit comprises: a blocking detector, connected to the controller and the bandpass filter, for detecting the signal strength of the blocking interference signal, and inputting the signal strength of the blocking interference signal to the controller; an adjacent channel detector, connected to the controller and the analog-to-digital converter, for detecting the signal strength of the adjacent channel interference signal, and inputting the signal strength of the adjacent channel interference signal to the controller; A signal strength detector, connected to the controller and the channel filter, for detecting the signal strength of a useful signal, and inputting the signal strength of the useful signal to the controller. A receiver, characterized in that it includes: Interconnected antennas and an adaptive anti-jamming device as claimed in any one of claims 11-18.

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