CN1355612A - Radio reception control device and method thereof - Google Patents

Abstract

A radio receiving controller is composed of AND gate coupled to output of receiver, counter connected to AND gate, feedback controller connected to counter and comparator, D/A converter coupled to feedback controller, and variable capacitance diode connected to D/A converter and local oscillator in receiver. The radio receiving control method utilizes the characteristic that when the carrier frequency between a radio transmitting device and a receiving device is shifted, the bit duration of the received data is changed, and the frequency of a local oscillation signal is adjusted by detecting the change of the bit duration of the received data so as to obtain the optimal receiving state.

Description

Radio reception control device and method thereof

The present invention relates to a radio reception control device and its method, in particular to a radio reception control device and its method which can automatically correct the receiving frequency.

With the continuous advancement of science and technology, electronic and communication technologies are also developing rapidly, especially wireless communication systems, which are developing rapidly. The portable electronic data receiving device has been widely used by the public as a real-time information display (Real Time Information Display). As far as the communication system is concerned, such as paging device (or called pager, pager, Beeper or B.B.Call), mobile phone (Mobile Phone) and other radio transmission devices, etc., have become quite important personal communication tools. In general radio communication systems, there are radio signal receiving devices whose main function is to receive external radio signals. Taking the paging device as an example, when the sender wants to send a message to the user of the pager, the sender sends the number of the pager at the receiving end and the information code to be delivered to the base station, and then the base station sends the message according to the number of the pager. radio signal to the called end. When the called end receives the wireless signal, the pager of the called end will notify the user that there is information coming in and display the information on the screen.

Referring to Figure 1, it shows a block diagram of a conventional radio receiver. In such a conventional radio receiver 100 , radio signals are received by an antenna 102 , and then a low-noise amplifier (Low-Noise Amplifier, LNA) 104 amplifies the received signal. The amplified signal is filtered by a radio frequency band-pass filter (Radio Frequency Band-Pass Filter, RF BPF) 106, and then sent to a mixer (Mixer) 108 after filtering out false image (Image) interference signals. The filtered signal and the local oscillator signal from the local oscillator (Local Oscillator) are received by the mixer 108 to generate an intermediate frequency signal (Intermediate Frequency, IF).

As shown in FIG. 1 , the IF signal output by the mixer 108 is filtered out by an IF bandpass filter (IF BPF) 12 and then amplified and output by an IF amplifier 114 . The amplified signal is demodulated by a demodulator (Demodulator) 116 and restored to obtain a base band analog signal (Base Band Analog Signal, BBAS) transmitted on the carrier. The baseband analog signal obtained after demodulation is sent to a low pass filter (Low Pass Filter) 118 to filter out the noise outside the baseband, and then sent to a voltage comparator (Comparator) 120. The voltage comparator 120 uses the reference voltage as a reference to convert the filtered baseband analog signal into a digital signal and then output it for processing by a digital circuit to read out the content of the received information.

In order to improve the performance of the radio receiver, the generally used intermediate frequency bandpass filter (also known as the channel filter, Channel Filter) has a bandwidth that allows the carrier modulation signal to pass through the minimum bandwidth required to improve Receive the Signal-to-NoiseRatio (S/N) of the signal and obtain a sufficient adjacent channel rejection ratio (Adjacent ChannelRejection).

When using this kind of traditional radio receiver 100 , the IF signal is generated by mixing the external carrier signal and the local oscillator signal output by the local oscillator 110 in the mixer 108 . However, when the IF frequency shifts, the received signal will be attenuated by the narrow bandwidth IF bandpass filter, resulting in a decrease in the sensitivity of the received signal and resulting in a bit error rate (Bit) of the data. Error Rate) rises. Therefore, the operation of the local oscillator 110 in the conventional radio receiver 100 must be very stable, and the output local oscillator frequency must be precisely adjusted so that the IF signal has a correct IF frequency.

Although in general analog signal receivers such as FM (Frequency Modulation) radios, automatic frequency control (Automatic Frequency Control, AFC) circuits are often configured. However, for the signal received in data transmission, since the signal 0 and the signal 1 are not symmetrical, that is, the numbers of data 0 and data 1 in the data are not necessarily equal. Moreover, in order to reduce the bandwidth required for transmission, the bit data is transmitted in the way of non-return to zero (NRZ) when transmitting the signal, so the local oscillator cannot be controlled by taking out the DC component of the received signal. Feedback Control.

Regarding the above-mentioned problems of decreased sensitivity of received signals and increased bit error rate of data caused by local oscillator frequency offset, the solutions generally adopted can be roughly divided into two types: one is to use a high-precision local oscillator; the other is to use a frequency Wide IF filter. However, when using a high-precision local oscillator in a radio receiver, it must spend a relatively high cost, and will cause the production process of the receiver to be complicated.

Moreover, since all parts in the radio receiver have their own temperature change characteristics, in order to prevent the local oscillation frequency from shifting due to temperature changes, it is necessary to cooperate with a temperature compensation circuit or use a constant temperature bath to keep the temperature of the entire system constant. . However, keeping the system at a constant temperature by means of a constant temperature bath consumes a large amount of power, and is not suitable for portable communication devices widely used by the public today. Furthermore, the aging phenomenon (Aging) of parts in the radio receiver due to use will also cause the local oscillator frequency to shift, so regular calibration is required to maintain its better use status. However, this will increase the cost of use and cause inconvenience to users, and it cannot solve the problem caused by the frequency offset of the radio signal transmitting end.

Between the radio transmitter and receiver, the frequency offset phenomenon caused by adjustment, temperature change and aging of parts can be improved by increasing the bandwidth of the intermediate frequency band-pass filter, but when increasing the frequency of the band-pass filter At the same time, part of the noise will also pass through the filter, thus reducing the sensitivity of the radio receiver. Moreover, this way of improving the frequency offset by increasing the bandwidth will also be ineffective due to the gradual increase in the frequency of the spectrum used by the radio, and the frequency offset phenomenon will be further deteriorated. In addition, due to the limited bandwidth of the IF frequency, it is impossible to increase it without limit, and it still needs to meet the requirements of the adjacent channel rejection ratio in the receiver specification, so when the frequency of the radio spectrum used gradually increases, this will lead to Increasing the bandwidth to improve frequency offset fails.

In view of the above-mentioned background of the invention, and when the carrier frequency is shifted between the radio transmitting device and the receiving device, it will cause the bit duration (Bit Duration) of the received data to change, so one of the main purposes of the present invention One is to provide a radio receiving control device, which uses an over-sampling circuit (Over Sampling eircuit) to detect the change of the bit duration of the received data, and adjusts the frequency of the local oscillator signal by means of feedback control after arithmetic processing. By correcting the local oscillation frequency, the frequency between the radio transmitting device and the receiving device is kept consistent, and the radio receiving device reaches the best receiving state, so as to improve its receiving sensitivity.

Another object of the present invention is to provide a radio reception control method that utilizes the characteristic that the bit duration of the data it receives changes when the carrier frequency shifts between the radio transmitting device and the receiving device. The mode detects the change of the bit duration of the received data, and then performs calculation processing, and then adjusts the frequency of the local oscillator signal in a feedback control mode to obtain the correct IF frequency of the receiving device and the lowest data bit error rate.

The radio receiving control device of the present invention is realized as follows: a radio receiving control device is used to control a radio receiving device, the radio receiving device is used to receive a radio signal, and the radio receiving device has an antenna, a mixing a frequency converter, a local oscillator, a demodulator and a comparator, the mixer is respectively coupled to the antenna and the local oscillator, the demodulator is respectively coupled to the mixer and the comparator, The radio reception control device is respectively coupled with the comparator and the local oscillator, wherein the radio reception control device at least includes: an AND gate, respectively coupled with the comparator and a sampling signal generator, for A digital signal output by the comparator is compared with an oversampling clock pulse signal output by the sampling signal generator, and a sampling value is output; a counter is coupled with the output kick of the AND gate for receiving The sampled value is counted to output a counted value; a feedback controller is respectively coupled to the counter and the comparator to receive the counted value from the counter and output according to the counted value a correction signal; a digital/analog converter coupled to the feedback controller for receiving the correction signal from the feedback controller to adjust a correction voltage output by the digital/analog converter; and a variable Capacitive diodes, respectively coupled to the digital/analog converter and the local oscillator, used to receive the correction voltage from the digital/analog converter, to change the capacitance value of the variable capacitance diode, and adjust the local oscillator the frequency of the device.

The radio receiving system of the present invention is realized like this: a kind of radio receiving system is characterized in that: wherein at least comprises: an antenna, in order to receive a radio signal; A mixer, is coupled with this antenna; A local oscillator , coupled with the mixer to generate a local oscillator signal, the radio signal and the local oscillator signal are received and acted on by the mixer to generate an intermediate frequency signal; a demodulator, coupled with the mixer , used to receive the intermediate frequency signal and generate a baseband analog signal; a comparator coupled to the demodulator, the comparator respectively receives a reference voltage and compares the baseband analog signal output by the demodulator , to generate a digital signal; an AND gate, coupled to the comparator, the AND gate respectively receives an oversampling clock pulse signal and compares it with the digital signal output by the comparator, and generates a sampling value; a counter , coupled with the AND gate, for receiving the sampled value for counting, to generate a count value; a feedback controller, coupled with the counter and the comparator, respectively, for receiving the count value output by the counter, and generate a correction signal according to the count value; a digital/analog converter coupled with the feedback controller to receive the correction signal to adjust a correction voltage output by the digital/analog converter; and a variable Capacitive diodes, respectively coupled to the digital/analog converter and the local oscillator, for receiving the correction voltage output by the digital/analog converter, so as to change the capacitance value of the variable capacitance diode and adjust the local oscillator the frequency of the device.

It also includes an amplifier coupled to the antenna and the mixer respectively.

It also includes a radio frequency band-pass filter coupled to the antenna and the mixer respectively.

It also includes an intermediate frequency band-pass filter coupled to the mixer and the demodulator respectively.

It also includes an intermediate frequency amplifier coupled to the mixer and the demodulator respectively.

It also includes a low-pass filter coupled to the demodulator and the comparator respectively.

The radio receiving system capable of automatically correcting the receiving frequency of the present invention is realized in the following way: a radio receiving system capable of automatically correcting the receiving frequency is characterized in that it at least includes: an antenna for receiving a radio signal; a signal amplifier, coupled with the antenna, for receiving and amplifying the radio signal; a radio frequency bandpass filter, coupled with the low noise amplifier, for filtering the radio signal amplified by the low noise amplifier; a mixer, coupled to the radio frequency bandpass filter, a local oscillator, coupled to the mixer, to generate a local oscillation signal, the radio signal and the local oscillation signal are received through the mixer and The function generates an intermediate frequency signal; an intermediate frequency bandpass filter is coupled with the mixer for receiving and filtering the intermediate frequency signal; an intermediate frequency amplifier is coupled with the intermediate frequency bandpass filter for receiving and amplifying the The intermediate frequency signal filtered by the intermediate frequency bandpass filter; a demodulator, coupled with the intermediate frequency amplifier, used to receive the intermediate frequency signal amplified by the intermediate frequency amplifier, and generate a baseband analog signal; a low pass filter , coupled with the demodulator, used to filter the baseband analog signal output by the demodulator; a comparator, coupled with the low-pass filter, the comparator respectively receives a reference voltage and the baseband Analog signals are compared to generate a digital signal; an AND gate is coupled to the comparator, and the AND gate respectively receives an oversampling clock pulse signal and compares it with the digital signal output by the comparator, and generates a sampling value; a counter, coupled with the AND gate, used to receive the sampled value for counting, to generate a count value; a feedback controller, respectively coupled with the counter and the comparator, used to receive the output of the counter the count value, and generate a correction signal according to the count value; a digital/analog converter coupled to the feedback controller to receive the correction signal to adjust the correction voltage output by the digital/analog converter; and a variable capacitance diode, respectively coupled to the digital/analog converter and the local oscillator, to receive the correction voltage output by the digital/analog converter, to change the capacitance value of the variable capacitance diode, and to adjust The frequency of the local oscillator.

The signal receiving control device of the present invention is realized in the following way: a signal receiving control device is used to control a signal receiving device, the signal receiving device is used to receive a signal, and the signal receiving device has a signal receiver, a a mixer, a local oscillator, a demodulator and a comparator, the mixer is respectively coupled to the signal receiver and the local oscillator, the demodulator is respectively connected to the mixer and the comparator Coupling, the signal receiving control device is respectively coupled to the comparator and the local oscillator, wherein the signal receiving control device at least includes: an AND gate, which is respectively coupled to the comparator and a sampling signal generator for Comparing a digital signal output by the comparator with an oversampling clock pulse signal output by the sampling signal generator, and outputting a sampling value; a counter, coupled with the output terminal of the AND gate, for receiving the sampling a value and counting the sampled value to output a count value; a feedback controller, coupled to the counter and the comparator respectively, for receiving the count value from the counter, and outputting a count value according to the count value a correction signal; a digital/analog converter coupled to the feedback controller for receiving the correction signal from the feedback controller to adjust a correction voltage output by the digital/analog converter; and a variable capacitor diodes, respectively coupled to the digital/analog converter and the local oscillator, to receive the correction voltage from the digital/analog converter, to change the capacitance value of the variable capacitance diode, and to adjust the local oscillator Frequency of.

The radio reception control method of the present invention is realized in this way: when receiving a radio signal and converting the radio signal into a corresponding digital signal, it is used to automatically correct the receiving frequency, and it is characterized in that: wherein the radio reception control method at least includes The following steps: sampling the digital signal with an oversampling ratio with an oversampling clock signal to generate a sampling value; counting the sampling value to generate a count value, the count value having at least one bit duration data; judging the relationship between the count value and the oversampling ratio, calculating and adjusting an output voltage; and adjusting a local oscillation frequency according to the output voltage.

Wherein the step of judging the relationship between the count value and the oversampling ratio and calculating and adjusting the output voltage further includes reducing the output voltage in a preset step when the bit duration data is 0.

Wherein, in the step of judging the relationship between the count value and the over-sampling ratio, calculating and adjusting the output voltage, it also includes stepping up the count value in a predetermined step when the count value is equal to a sampling data length multiplied by the over-sampling ratio. high the output voltage.

Wherein, in the above step of judging the relationship between the count value and the oversampling ratio, calculating and adjusting the output voltage, it also includes when the count value is not equal to a sampling data length multiplied by the oversampling ratio, and the bit duration data is greater than The sum of the oversampling ratio and an allowable range adjusts the output voltage according to the difference between the bit duration data and the sum of the oversampling ratio and the allowable range.

Wherein, in the step of judging the relationship between the count value and the oversampling ratio, calculating and adjusting the output voltage, it also includes when the bit duration data is not equal to zero and is less than the difference between the oversampling ratio and a permissible range, according to the bit The difference between the duration data and the sum of the oversampling ratio and the tolerance range adjusts the output voltage.

The signal receiving control method of the present invention is realized as follows: a signal receiving control method is used to automatically correct the receiving frequency when receiving a signal and converting the signal into a corresponding digital signal, wherein the signal receiving control method at least The method comprises the following steps: sampling the digital signal with an oversampling ratio with an oversampling clock pulse signal to generate a sample value; counting the sample value to generate a count value, the count value having at least one bit duration time data; and adjusting a local oscillator frequency according to the output voltage, so that a local oscillator signal with the local oscillator frequency is mixed with the signal.

Wherein, in the step of judging the relationship between the count value and the oversampling ratio, and calculating and adjusting the output voltage, it also includes reducing the output voltage by a preset step when the bit duration data is 0.

Wherein, in the step of judging the relationship between the count value and the over-sampling ratio, calculating and adjusting the output voltage, it also includes stepping up the count value in a predetermined step when the count value is equal to a sampling data length multiplied by the over-sampling ratio. high the output voltage.

Wherein, in the above step of judging the relationship between the count value and the oversampling ratio, calculating and adjusting the output voltage, it also includes when the count value is not equal to a sampling data length multiplied by the oversampling ratio, and the bit duration data is greater than The sum of the oversampling ratio and an allowable range adjusts the output voltage according to the difference between the bit duration data and the sum of the oversampling ratio and the allowable range.

Wherein, in the step of judging the relationship between the count value and the oversampling ratio, calculating and adjusting the output voltage, it also includes when the bit duration data is not equal to zero and is less than the difference between the oversampling ratio and a permissible range, according to the bit The difference between the duration data and the sum of the oversampling ratio and the tolerance range adjusts the output voltage.

The present invention is a radio receiving control device for controlling a radio receiving device having an antenna, a mixer, a local oscillator, a demodulator and a comparator. The radio receiving control device has an AND Gate, a Counter, a Feedback Controller, a Digital/Analog Converter, and a Variable Capacitance Diode. Among them, the AND gate is coupled with the comparator in the radio receiving device, the counter is connected with the AND gate, the feedback controller is respectively connected with the counter, and the digital/analog converter is coupled with the feedback controller, and the variable capacitance diode is respectively Interface with digital/analog converters and local oscillators in radio receivers.

Moreover, according to the above and other purposes of the present invention, the present invention provides a radio receiving system, wherein there is an antenna for receiving signals; a mixer for generating an intermediate frequency signal is respectively coupled to the antenna and a local oscillator; The device is respectively coupled with the mixer and the low-pass filter to generate the baseband analog signal; the AND gate is respectively connected with the comparator and the counter to receive the oversampling control signal and the digital signal from the comparator to generate the sampled value ; and the feedback controller is respectively coupled with the counter and the digital/analog converter to receive the count value output by the counter to generate a correction signal to the digital/analog converter; the variable capacitance diode is respectively connected to the digital/analog converter and the local oscillator Connected to the digital/analog converter to adjust and change its capacitance value, so as to correct the frequency of the local oscillator.

In addition, according to the above and other objects of the present invention, the present invention also provides a radio reception control method.

The above-mentioned and other objects, features and advantages of the present invention are described in detail below in conjunction with preferred embodiments and accompanying drawings:

Fig. 1 is a block diagram of a conventional radio receiver.

FIG. 2 is a schematic block diagram of a radio receiving system according to a preferred embodiment of the present invention.

FIG. 3 is a schematic diagram of a frequency spectrum when the local oscillator frequency and the center frequency of the carrier can be out of the correct intermediate frequency.

FIG. 4 is a comparison diagram of the baseband analog signal and its corresponding digital signal when the local oscillator frequency and the carrier center frequency can be out of the correct intermediate frequency.

FIG. 5 is a schematic diagram of the frequency spectrum when the intermediate frequency obtained by the beat difference between the local oscillator frequency and the carrier center frequency has an offset.

FIG. 6 is a comparison diagram of the baseband analog signal and its corresponding digital signal when the intermediate frequency obtained by the beat difference between the local oscillator frequency and the carrier center frequency has an offset.

FIG. 7 is a schematic flowchart of a radio reception control method according to a preferred embodiment of the present invention.

FIG. 8 is a timing diagram of various signals when the carrier center frequency becomes higher or the local oscillation frequency becomes lower, and fine-tuning is performed according to a preferred embodiment of the present invention, a radio reception control method.

FIG. 9 is a timing diagram of various signals when the carrier center frequency becomes lower or the local oscillation frequency becomes higher, and fine-tuning is performed according to a preferred embodiment of the present invention, a radio reception control method.

FIG. 10 is a timing diagram of various signals when frequency correction is performed when the local oscillator frequency deviates too much from the center frequency of the carrier in a radio reception control method according to a preferred embodiment of the present invention.

Please refer to FIG. 2 , which shows a schematic block diagram of a radio receiving system according to a preferred embodiment of the present invention. The radio receiving system 200 includes a radio receiving device 202 and a radio receiving control device 204 . The radio receiving device 202 is similar to a traditional radio receiver, having an antenna 210, a low noise amplifier 212, a radio frequency bandpass filter 214, a mixer 216, a local oscillator 218, an intermediate frequency bandpass filter 220, an intermediate frequency amplifier 222, A demodulator 224 , a low-pass filter 226 and a comparator 228 .

As shown in FIG. 2 , in the radio receiving device 202 , the antenna 210 is used to receive a radio signal 230 generated from a corresponding radio transmission system, such as a radio signal sent by a base station. The low noise amplifier 212 is respectively connected to the antenna 210 and the RF band-pass filter 214 to amplify the radio signal 230 and output it to the RF band-pass filter 214 to filter out false image interference signals. The mixer 216 is coupled to the RF bandpass filter 214 and the local oscillator 218 to receive the filtered radio signal 230 and the local oscillator signal 232 from the local oscillator 218 and generate an intermediate frequency signal 234 .

Intermediate frequency band-pass filter 220 among Fig. 2 is connected with mixer 216, intermediate frequency amplifier 222 respectively, after intermediate frequency signal 234 filters out the noise outside all reception channels through intermediate frequency band-pass filter 220, then by intermediate frequency amplifier 222 it amplified output. The demodulator 224 is respectively coupled with the intermediate frequency amplifier 222 and the low-pass filter 226, and the amplified intermediate frequency signal 234 is restored by the demodulator 224 into a baseband analog signal (BBAS) 236 transmitted on the carrier, and sent to the low-pass The filter 226 filters out noise outside the baseband. The voltage comparator 228 is connected with the low-pass filter 226, and its input terminal respectively receives the filtered baseband analog signal 236 and the reference voltage 238, and uses the reference voltage 238 as a reference to convert the baseband analog signal 236 into a digital signal 240 output for other digital circuits (not shown in the figure) to interpret the content of the received information.

The radio reception control device 204 in Fig. 2 is used to control the radio reception device 202, has an AND gate 250, a counter 252, a feedback controller 254, a digital/analog converter 256, a variable capacitance diode 258 and an oversampling clock pulse generator 260. Wherein the AND gate 250 is respectively coupled with the counter 252 and the voltage comparator 228 in the radio receiving device 202, and its input terminal receives the digital signal 240 from the voltage comparator 228 and the higher than data transmission from the oversampling clock pulse generator 260 respectively. rate oversampling the clock signal 242 . The AND gate 250 compares the input signals to generate a sampled value 244 , and outputs it to the counter 252 . The counter 252 receives and counts the sampled value 244 from the AND gate 250 and generates a count value 246 for output. This count value is the bit duration of the data in the received signal.

Feedback controller 254 in Fig. 2 is coupled with counter 252, digital/analog converter 256, comparator 228 in radio receiving device 202 respectively, in order to receive the count value 246 that counter 252 outputs, and according to this count value 246 carry out The calculation process then generates a correction signal 248 . The D/A converter 256 receives the correction signal 248 from the feedback controller 254 and generates a corresponding correction voltage 262 . The variable capacitance diode 258 is connected to the digital/analog converter 256 and the local oscillator 218 in the radio receiving device 202 respectively, and the variable capacitance diode 258 receives the correction voltage 262 output by the digital/analog converter 256, so as to change the radio receiving voltage. The frequency of the local oscillator signal 232 output by the local oscillator 218 in the device 202 .

The local oscillator 218 in the receiving device 202 of the radio receiving system 200 is used to generate a local oscillator signal 232 . The radio transmitting system corresponding to the radio receiving system 200 uses a carrier to transmit information, which also has a specific center frequency of the carrier. When both the frequency of the local oscillator signal 232 and the center frequency of the carrier can be beat out to the correct IF frequency in the mixer 216, an IF bandpass filter with the minimum bandwidth required to allow the carrier modulation signal to pass through can be used. Reduce noise to improve the signal-to-noise ratio of the signal.

However, the present invention can also be applied to wired electric signal receiving control, wherein the radio signal receiving device can be changed to a wired electric signal receiving device, and the antenna used to receive the radio signal can be changed to a cable used to transmit the wired electric signal.

Please refer to Figure 3, which shows the spectrum diagram when the local oscillator frequency and the carrier center frequency can beat the correct intermediate frequency frequency, where the horizontal axis represents the frequency, F _RF is the carrier center frequency, f _{RF ΔF} and f _RF+ΔF signal frequency, F _LO is the local oscillator frequency, F _IF is the intermediate frequency signal frequency, in this example, F _IF ＝F _RF -F _LO , and BW _IF is the bandwidth of the intermediate frequency bandpass filter (BW _IF ≈2ΔF) .

Figure 4 shows the contrast between the baseband analog signal (BBAS) and its corresponding digital signal when the local oscillator frequency and the carrier center frequency can beat the correct intermediate frequency. The horizontal axis represents time, and the vertical axis represents is the voltage. As mentioned above, the baseband analog signal 400 in the figure is obtained from the intermediate frequency signal through the demodulator and the baseband low-pass filter, and the digital signal 402 corresponding to the baseband analog signal 400 is obtained from the baseband analog signal and The reference voltage (V _ref ) is generated after being compared by a voltage comparator. When the local oscillator frequency and the carrier center frequency can beat the correct IF frequency, the baseband analog signal (BBAS) 400 is symmetrical to the reference voltage (V _ref ), so the digital 0/1 signal 402 output by the voltage comparator has the correct bit Duration (T _b ).

When the intermediate frequency obtained by the beat difference between the carrier frequency of the radio transmitting system and the local oscillation frequency of the radio receiving system deviates, the intermediate frequency signal is attenuated by the intermediate frequency band-pass filter, resulting in a decrease in signal receiving sensitivity. Please refer to FIG. 5 , which shows a schematic diagram of the frequency spectrum when the IF frequency obtained by the beat difference between the local oscillator frequency and the carrier center frequency has an offset. Figure 5 is similar to Figure 3, where the horizontal axis represents frequency, and the same signals are represented by the same symbols, while F _LO' is the offset local oscillator frequency, F _IF' is the offset intermediate frequency signal frequency, and F _IF' =F _RF -F _LO' , and BW _IF is the bandwidth of the intermediate frequency bandpass filter (BW _IF ≈2ΔF).

FIG. 6 shows a comparison diagram of baseband analog signals and digital signals corresponding to FIG. 5 . As shown in Figure 6, when the intermediate frequency obtained by the beat difference between the local oscillator frequency and the carrier center frequency has an offset, the offset of the intermediate frequency results in an offset of the DC voltage, causing the baseband analog signal 600 to be asymmetrical to the reference voltage (V _ref ), thereby causing the corresponding digital signal 602 to generate an incorrect bit duration.

Using the radio receiving control device of the present invention can improve the bad influence of frequency offset, please refer to Fig. 2, generate oversampling control signal 242 with oversampling clock pulse generator 260, and make the rate higher than the oversampling control signal of data transmission 242 and the digital signal 240 are processed through the AND gate 250 and the counter 252, and the count value 246 with bit duration information is obtained after sampling and counting, and then the count value 246 is sent to the feedback controller 254 for calculation to adjust the radio The frequency of the local oscillator 218 in the receiving device 202 .

Please refer to FIG. 7 , which shows a schematic diagram of a control flow of a radio reception control method according to a preferred embodiment of the present invention. Please refer to FIG. 7 and FIG. 2 at the same time. When controlling radio signal reception, as shown in step 700 in FIG. converted to digital signal output. The digital signal is not only used for the digital circuit to interpret the content of the received information, but also used for automatic frequency control. For example, when the radio receiving system 200 is used, the radio receiving control device 204 is activated to amplify and filter the received radio signal, and mix it with the local oscillation signal to generate an intermediate frequency signal. Then filter and amplify the intermediate frequency signal, and then restore it to the baseband analog signal transmitted by the carrier. After filtering out noise, the baseband analog signal is compared with the reference voltage to generate a digital signal output for interpreting the content of the received information and for feedback control by the radio receiving control device 204 .

Secondly, the over-sampling ratio (Over-Sampling Ratio) of the digital signal is judged to be N by using the over-sampling clock pulse signal to generate the sampling signal, and then the sampling signal is counted to obtain the count value BD with bit duration D data (Bit Duration), wherein the oversampling ratio N is the ratio of the oversampling clock pulse signal to the symbol rate (Symbol Rate). When the sampling carried out is a single sampling, the bit duration is equal to the count value (D=BD); if it is an average sampling, the bit duration is the count value divided by the number H of the sampling signal being logic 1 in the sampling data length S , that is, D=BD/H, wherein the sampling data length S is the basis for the preset pause time (Time Out) of the scanning mode (Scanning Mode), and the general sampling data length S is greater than the transmission length of the maximum continuous logic 1 in the system, so as to Avoid wrong actions. When step 702 in FIG. 7 is performed, the allowable deviation range of the acquired bit duration and oversampling ratio is judged. When the obtained bit duration D is within the allowable deviation range of the oversampling ratio N, that is, NM≦D≦N+M, and M is the allowable deviation value, the frequency correction is not performed on the local oscillator signal, and then this step 702 is repeated, This is the signal tracking mode (Tracking Mode). In this following mode, the feedback controller in the control device will not update the output voltage of the digital/analog converter (V _DAC ), and the variable capacitance diode maintains its existing capacitance value because the control voltage does not change, so it is not suitable for receiving The local oscillator in the device performs frequency correction.

If the bit duration D is not within the allowable deviation range of the oversampling ratio, then proceed to step 704 in FIG. for low potential. If the obtained bit duration D is all 0, and the received data is all low potential, then proceed to step 706 in FIG. _DAC =V _DAC -V _STEP , coarsely adjust the local oscillator frequency for fast correction, and then perform step 702 again.

If in step 704, the bit duration D obtained is not all 0, then step 708 in Fig. 7 is performed, whether the obtained count value BD is equal to the sampling data length S multiplied by the oversampling ratio N, that is, Whether the received data has no high or low potential change and is all high potential. If the received data has no change in high and low potentials and is all high potentials (BD=S×N), then proceed to step 710 in FIG. 7 to increase the output voltage of the digital/analog converter with a preset step: That is, V _DAC =V _DAC +V _STEP , coarsely adjust the local oscillator frequency for fast correction, and then perform step 702 again.

The bit duration D does not fall within the allowable deviation range of the oversampling ratio, and the received data has high and low potential changes, then perform step 712 in FIG. 7, according to the difference between the bit duration D and the oversampling ratio N, and The corresponding ratio between the frequency change and the voltage change, adjust the output voltage of the digital/analog converter, fine-tune the local oscillation frequency, and expect the bit duration D to fall within the allowable deviation range of the oversampling ratio, and then proceed to step 702 again , this is the signal fine tuning mode (Fine Tune Mode).

When the carrier center frequency of the radio transmitting system becomes higher or the local oscillation frequency of the radio receiving system becomes lower, the intermediate frequency car output by the mixer will increase accordingly, thus causing the DC component in the baseband analog signal generated by demodulation The increase causes the bit duration of logic 1 in the digital signal output by the voltage comparator to become longer, and the increased bit duration causes the count value output by the counter to increase. In the signal fine-tuning mode, after the feedback controller reads the count value, it corrects the output voltage of the digital/analog converter according to the deviation between the bit duration D and the oversampling ratio N, thereby changing the capacitance of the variable capacitance diode. Reduce the capacitance of the variable capacitance diode to increase the frequency of the local oscillator, repeat the fine-tuning to make the bit duration value within the allowable range, and achieve the purpose of matching the receiving frequency of the receiving system with the transmitting system.

Conversely, when the carrier center frequency of the radio transmitting system becomes lower or the local oscillator frequency of the radio receiving system becomes higher, the above-mentioned method can be used for correction, increasing the capacitance of the variable capacitor diode to lower the frequency of the local oscillator. Then repeat the fine-tuning, so that the bit duration value is within the allowable range, so as to achieve the purpose of making the receiving frequency of the receiving system consistent with that of the transmitting system.

Please refer to Figure 8, which shows the timing diagram of various signals when the carrier center frequency becomes higher or the local oscillation frequency becomes lower, and fine-tuning is performed. These include radio signal F _TX (including f _RF-ΔF and f _RF+ΔF ), local oscillator signal F _LO , intermediate frequency signal F _IF , baseband analog signal (BBAS), digital signal (DATA), output voltage signal (V _DAC ). Fig. 9 is similar to Fig. 8, and it shows timing charts of various signals when the carrier center frequency becomes lower or the local oscillation frequency becomes higher, and fine-tuning is performed.

When the receiving frequency of the radio receiving system deviates too much from the carrier center frequency of the transmitting system, the digital signal output by the voltage comparator will no longer change with the modulation signal of the transmitting system, and the feedback controller uses the bit output by the counter Duration, can enter the scan mode after the preset pause time, adjust the output voltage of the digital / analog converter with the preset voltage step, so that the output voltage increases or decreases, by changing the variable capacitance diode Capacitance is used to roughly adjust the output frequency of the local oscillator, which is steps 704-710 in FIG. 7 . When the digital signal output by the receiving system changes with the modulation signal of the transmitting system again, the feedback controller will perform fine-tuning mode again, so that the system as a whole has the best transceiver frequency consistency.

Please refer to Figure 10, which shows the timing diagram of various signals when the local oscillator frequency deviates too much from the carrier center frequency and the frequency is corrected. Figure 10 is similar to Figure 8 and Figure 9, including radio signal F _TX (including f _RF-ΔF and f _RF+ΔF ), local oscillator signal F _LO , intermediate frequency signal F _IF , baseband analog signal (BBAS), digital signal , The output voltage signal (V _DAC ) is in the scan mode in the middle of the entire sequence, and in the fine-tuning mode in the latter stage of the sequence.

It can be seen from the above preferred embodiments of the present invention that the present invention can be applied to a wired or wireless receiving device that transmits digital data signals or analog signals in carrier frequency offset modulation. The present invention utilizes the characteristic that when the carrier frequency of the sending end and the receiving end deviates, the bit duration of the received data will change, and automatically corrects the receiving frequency. Application of the present invention has the following characteristics:

1. The present invention detects the variation of the duration of its bit with an oversampling circuit, and corrects the local oscillation frequency of the receiving end through feedback after calculation, so that the receiving end is locked on the carrier frequency consistent with the sending end, and the correct intermediate frequency of the receiving end is obtained. Frequency, therefore, an intermediate frequency band-pass filter with the minimum bandwidth can be used to reduce noise, change receiving sensitivity, and improve the performance of the receiving system.

2. The present invention adopts a closed loop (Closed Loop) control method, which can reduce the requirement for the precision of the local oscillator, so a lower-precision local oscillator can be used, for example, a low-precision quartz crystal can be used as the local oscillator The frequency control components are used to reduce the cost of parts and the cost required for production and adjustment, and can also solve the problem caused by the carrier frequency offset at the transmitting end.

3. The present invention can also use software to establish a test mode (Test Mode), which can be automatically corrected during mass production, which can save manual adjustment costs required by traditional production methods.

Claims (19)

1. A radio receiving control device, used to control a radio receiving device, the radio receiving device is used to receive a radio signal, and the radio receiving device has an antenna, a mixer, a local oscillator, a solution Modulator and a comparator, the mixer is respectively coupled with the antenna and the local oscillator, the demodulator is respectively coupled with the mixer and the comparator, the radio reception control device is respectively connected with the comparator And the local oscillator is coupled, characterized in that: wherein the radio reception control device at least includes: an AND gate, respectively coupled with the comparator and a sampling signal generator, for a digital signal output by the comparator Comparing with an oversampling clock pulse signal output by the sampling signal generator, and outputting a sampling value; a counter, coupled with the output kick of the AND gate, for receiving the sampling value and counting the sampling value , to output a count value; a feedback controller, respectively coupled with the counter and the comparator, for receiving the count value from the counter, and outputting a correction signal according to the count value; a digital/analog converter , coupled with the feedback controller, used to receive the correction signal from the feedback controller to adjust a correction voltage output by the digital/analog converter; and a variable capacitance diode, respectively connected to the digital/analog converter The oscillator is coupled to the local oscillator for receiving the correction voltage from the digital/analog converter to change the capacitance of the variable capacitance diode and adjust the frequency of the local oscillator. 2. A radio receiving system, characterized in that it at least includes: an antenna for receiving a radio signal; a mixer coupled with the antenna; a local oscillator coupled with the mixer, It is used to generate a local oscillator signal, and the radio signal and the local oscillator signal are received and acted on by the mixer to generate an intermediate frequency signal; a demodulator is coupled to the mixer to receive the intermediate frequency signal, and A baseband analog signal is generated; a comparator is coupled to the demodulator, and the comparator respectively receives a reference voltage and compares the baseband analog signal output by the demodulator to generate a digital signal; and A gate is coupled with the comparator, and the AND gate respectively receives an oversampling clock pulse signal and compares it with the digital signal output by the comparator, and generates a sampling value; a counter, coupled with the AND gate, uses counting by receiving the sampled value to generate a count value; a feedback controller, coupled to the counter and the comparator respectively, for receiving the count value output by the counter, and generating a correction signal according to the count value ; a digital/analog converter coupled to the feedback controller for receiving the correction signal to adjust a correction voltage output by the digital/analog converter; and a variable capacitance diode connected to the digital/analog respectively The converter is coupled to the local oscillator for receiving the correction voltage output by the digital/analog converter to change the capacitance of the variable capacitance diode and adjust the frequency of the local oscillator. 3. The radio receiving system as claimed in claim 2, further comprising an amplifier coupled to the antenna and the mixer respectively. 4. The radio receiving system as claimed in claim 2, further comprising a radio frequency bandpass filter coupled to the antenna and the mixer respectively. 5. The radio receiving system as claimed in claim 2, further comprising an intermediate frequency bandpass filter coupled to the mixer and the demodulator respectively 6. The radio receiving system as claimed in claim 2, further comprising an intermediate frequency amplifier coupled to the mixer and the demodulator respectively. 7. The radio receiving system as claimed in claim 2, further comprising a low-pass filter coupled to the demodulator and the comparator respectively. 8. A radio receiving system capable of automatically correcting the receiving frequency, characterized in that it at least includes: an antenna for receiving a radio signal; a low noise amplifier coupled with the antenna for receiving and amplifying the radio signal radio signal; a radio frequency bandpass filter, coupled with the low noise amplifier, used to filter the radio signal amplified by the low noise amplifier; a mixer, coupled with the radio frequency bandpass filter, a A local oscillator, coupled with the mixer, is used to generate a local oscillation signal, and the radio signal and the local oscillation signal are received and acted on by the mixer to generate an intermediate frequency signal; an intermediate frequency bandpass filter, and the A mixer is coupled to receive and filter the intermediate frequency signal; an intermediate frequency amplifier is coupled to the intermediate frequency bandpass filter to receive and amplify the intermediate frequency signal filtered by the intermediate frequency bandpass filter; a demodulator A device, coupled to the intermediate frequency amplifier, is used to receive the intermediate frequency signal amplified by the intermediate frequency amplifier, and to generate a baseband analog signal; a low-pass filter, coupled to the demodulator, is used to filter the The baseband analog signal output by the tuner; a comparator, coupled with the low-pass filter, the comparator respectively receives a reference voltage and compares the baseband analog signal to generate a digital signal; an AND gate, Coupled with the comparator, the AND gate respectively receives an oversampling clock pulse signal and compares it with the digital signal output by the comparator, and generates a sampling value; a counter, coupled with the AND gate, is used to receive The sampled value is counted to generate a count value; a feedback controller is respectively coupled to the counter and the comparator to receive the count value output by the counter and generate a correction signal according to the count value; a digital/analog converter coupled to the feedback controller for receiving the correction signal to adjust the correction voltage output by the digital/analog converter; and a variable capacitance diode connected to the digital/analog converter and The local oscillator is coupled to receive the correction voltage output by the digital/analog converter, so as to change the capacitance of the variable capacitance diode and adjust the frequency of the local oscillator. 9. A signal receiving control device, used to control a signal receiving device, the signal receiving device is used to receive a signal, and the signal receiving device has a signal receiver, a mixer, a local oscillator, a A demodulator and a comparator, the mixer is respectively coupled to the signal receiver and the local oscillator, the demodulator is respectively coupled to the mixer and the comparator, the signal receiving control device is respectively connected to The comparator and the local oscillator are coupled, and it is characterized in that: the signal receiving control device at least includes: an AND gate, respectively coupled with the comparator and a sampling signal generator, for the output of the comparator A digital signal is compared with an oversampling clock pulse signal output by the sampling signal generator, and a sampling value is output; a counter is coupled with the output terminal of the AND gate to receive the sampling value and the sampling value value to count, to output a count value; a feedback controller, respectively coupled with the counter and the comparator, for receiving the count value from the counter, and outputting a correction signal according to the count value; a digital/ an analog converter coupled to the feedback controller for receiving the correction signal from the feedback controller to adjust a correction voltage output by the digital/analog converter; and a variable capacitance diode connected to the digital The /analog converter is coupled to the local oscillator for receiving the correction voltage from the digital/analog converter to change the capacitance of the variable capacitance diode and adjust the frequency of the local oscillator. 10. A radio reception control method for automatically correcting the reception frequency when receiving a radio signal and converting the radio signal into a corresponding digital signal, wherein the radio reception control method at least includes the following steps: Sampling the digital signal with an oversampling ratio with an oversampling clock pulse signal to generate a sample value; counting the sample value to generate a count value, the count value has at least one bit duration data; judging Calculate and adjust an output voltage according to the relationship between the count value and the oversampling ratio; and adjust a local oscillation frequency according to the output voltage. 11. The radio receiving control method as claimed in claim 10, wherein in the step of judging the relationship between the count value and the oversampling ratio, calculating and adjusting the output voltage, it also includes when the bit duration data When 0, the output voltage is reduced by a preset step. 12. The radio receiving control method as claimed in claim 10, wherein in the step of judging the relationship between the count value and the oversampling ratio, calculating and adjusting the output voltage, it further includes when the count value is equal to one When the sampled data length is multiplied by the oversampling ratio, the output voltage is increased with a preset step. 13. The radio receiving control method as claimed in claim 10, wherein in the step of judging the relationship between the count value and the oversampling ratio, calculating and adjusting the output voltage, it also includes when the count value is not equal to A sampling data length is multiplied by the oversampling ratio, and the bit duration data is greater than the sum of the oversampling ratio and an allowable range, and adjusted according to the difference between the bit duration data and the sum of the oversampling ratio and the allowable range the output voltage. 14. The radio receiving control method as claimed in claim 10, wherein in the step of judging the relationship between the count value and the oversampling ratio, calculating and adjusting the output voltage, it also includes when the bit duration data Not equal to zero but less than the difference between the oversampling ratio and an allowable range, the output voltage is adjusted according to the difference between the bit duration data and the sum of the oversampling ratio and the allowable range. 15. A signal reception control method, used to automatically correct the reception frequency when receiving a radio signal and converting the radio signal into a corresponding digital signal, characterized in that the radio reception control method at least includes the following steps: Sampling the digital signal with an oversampling ratio with an oversampling clock pulse signal to generate a sample value; counting the sample value to generate a count value, the count value has at least one bit duration data; judging Calculate and adjust an output voltage according to the relationship between the count value and the oversampling ratio; and adjust a local oscillation frequency according to the output voltage. 16. The radio reception control method as claimed in claim 15, wherein in the step of judging the relationship between the count value and the oversampling ratio, calculating and adjusting the output voltage, it also includes when the bit duration data When 0, the output voltage is reduced by a preset step. 17. The radio receiving control method as claimed in claim 15, wherein in the step of judging the relationship between the count value and the oversampling ratio, calculating and adjusting the output voltage, it further includes when the count value is equal to one When the sampled data length is multiplied by the oversampling ratio, the output voltage is increased with a preset step. 18. The radio receiving control method as claimed in claim 15, wherein in the step of judging the relationship between the count value and the oversampling ratio, calculating and adjusting the output voltage, it also includes when the count value is not equal to A sampling data length is multiplied by the oversampling ratio, and the bit duration data is greater than the sum of the oversampling ratio and an allowable range, and adjusted according to the difference between the bit duration data and the sum of the oversampling ratio and the allowable range the output voltage. 19. The radio reception control method as claimed in claim 15, wherein in the step of judging the relationship between the count value and the oversampling ratio, calculating and adjusting the output voltage, it also includes when the bit duration data Not equal to zero but less than the difference between the oversampling ratio and an allowable range, the output voltage is adjusted according to the difference between the bit duration data and the sum of the oversampling ratio and the allowable range.

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