CN119602816A - Carrier elimination system and method based on automatic tuning - Google Patents
Carrier elimination system and method based on automatic tuning Download PDFInfo
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- CN119602816A CN119602816A CN202510142450.2A CN202510142450A CN119602816A CN 119602816 A CN119602816 A CN 119602816A CN 202510142450 A CN202510142450 A CN 202510142450A CN 119602816 A CN119602816 A CN 119602816A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B5/00—Near-field transmission systems, e.g. inductive or capacitive transmission systems
- H04B5/70—Near-field transmission systems, e.g. inductive or capacitive transmission systems specially adapted for specific purposes
- H04B5/77—Near-field transmission systems, e.g. inductive or capacitive transmission systems specially adapted for specific purposes for interrogation
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
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Abstract
The invention provides an automatic tuning-based carrier elimination system and an automatic tuning-based carrier elimination method, wherein the system comprises an orthogonal phase splitter, an adder, an output circuit connected with the adder, and a first circuit and a second circuit arranged between the orthogonal phase splitter and the adder, wherein a carrier signal of a radio frequency end to be processed is input into a coupling carrier input end of the orthogonal phase splitter and forms two paths of signals after passing through the orthogonal phase splitter, the two paths of signals are respectively input into the first circuit and the second circuit, the output signals of the first circuit and the second circuit are subjected to combining processing through the adder and output combined signals to the output circuit, the combined signals and initial signals are subjected to subtracting and round inspection processing through the output circuit and a preset round inspection algorithm, and a modulation signal after the carrier signal is eliminated is obtained, and the initial signals comprise the carrier signal and the corresponding modulation signal. The carrier wave elimination can be realized by using the passive device.
Description
Technical Field
The invention relates to the technical field of signal transmission, in particular to a carrier wave elimination system and method based on automatic tuning.
Background
RFID (Radio Frequency Identification ) is a non-contact automatic identification technology, mainly uses magnetic field or electromagnetic field as medium to make energy and information transfer so as to implement information interaction between host machine and tested object.
Currently, in an RFID system, in order to provide energy to a tag chip, a reader-writer needs to continuously transmit a very large continuous carrier signal without modulation, and the carrier signal leaks into the front end of a receiver through a circulator or a directional coupler, and the receiving and transmitting signals are determined to be the same carrier frequency due to a return mechanism of tag backscattering. Therefore, the leaked carrier signal cannot be filtered out by the radio frequency band-pass filter at the receiving front end, so that the desensitization and blocking are generated at the front end of the receiver, and the dynamic state of a receiving link is affected.
Disclosure of Invention
In view of the above problems, the present invention provides a carrier cancellation system and method based on auto-tuning, so as to solve the problem that the existing carrier signal that cannot be filtered out is desensitized and blocked at the front end of the receiver, and affects the dynamics of the receiving link.
The invention provides an automatic tuning-based carrier cancellation system, which comprises a quadrature phase splitter, an adder, an output circuit connected with the adder, and a first circuit and a second circuit which are arranged between the quadrature phase splitter and the adder,
The carrier signal of the radio frequency end to be processed is input into the coupling carrier input end of the quadrature phase splitter, and two paths of signals are formed after passing through the quadrature phase splitter;
the two paths of signals are respectively input into the first circuit and the second circuit;
the output signals of the first circuit and the second circuit are subjected to combining processing through the adder, and the combined signal is output to the output circuit;
And subtracting and round-robin processing is carried out on the combined signal and the initial signal through the output circuit and a preset round-robin algorithm to obtain a modulation signal after eliminating the carrier signal, wherein the initial signal comprises the carrier signal and the corresponding modulation signal.
In addition, the first circuit comprises a first balun, a first switch, a second balun and a first numerical control attenuator which are sequentially connected, wherein,
The first balun is used for carrying out balanced and unbalanced conversion on one of the two signals;
The first switch is used for carrying out phase inversion on the signals after balanced and unbalanced conversion;
the second balun is used for carrying out balanced and unbalanced conversion on the signals after phase inversion;
the first numerical control attenuator is used for adjusting and controlling the amplitude and the phase of the signal output by the second balun.
In addition, the second circuit comprises a third balun converter, a second switch switcher, a fourth balun converter and a second digital attenuator which are connected in sequence, wherein,
The third balun is used for conducting balance and unbalance conversion on the other signal in the two signals;
the second switch switcher is used for carrying out phase inversion on the signals after balanced and unbalanced conversion;
The fourth balun is used for conducting balanced and unbalanced conversion on the signals after phase inversion;
The second digital attenuator is used for adjusting and controlling the amplitude and the phase of the signal output by the fourth balun transformer.
In addition, the optional technical scheme is that the phase difference between the two paths of signals is 90 degrees.
In addition, the optional technical scheme is that the output circuit comprises a combiner and an amplifier which are connected in sequence, and the initial signal and the combined signal are both input into the combiner;
The combiner is used for subtracting the combined signal and the initial signal;
The amplifier is used for amplifying and outputting the modulation signal output by the combiner.
In addition, the optional technical proposal is that the device also comprises a coupler connected with the amplifier, and a detector and an MCU which are sequentially connected with the coupler,
The MCU is used for controlling the states of the first circuit and the second circuit according to the voltage value of the detector.
Furthermore, an optional technical solution is that the state of the first circuit includes a switching state of the first switch switcher and an attenuation value of the first digitally controlled attenuator;
The state of the second circuit includes a switching state of the second switch switcher and an attenuation value of the second digital attenuator.
In addition, an optional technical scheme is that the preset round inspection algorithm comprises:
The MCU is used for controlling the first switch switcher and the second switch switcher to overturn the phases of signals in corresponding circuits respectively so as to enable the phases of the carrier signal and the initial signal to be opposite and offset, meanwhile, the voltage value of the detector is monitored, when the voltage value is the minimum value, the phases are judged to meet the opposite relation, and the switch states of the first switch switcher and the second switch switcher are locked.
In addition, the optional technical scheme is that the preset round inspection algorithm further comprises:
And monitoring the voltage value of the detector through the MCU, adjusting the attenuation values of the first numerical control attenuator and the second numerical control attenuator, and locking the attenuation values of the first numerical control attenuator and the second numerical control attenuator and fixedly setting when the voltage value is the minimum value.
On the other hand, the invention also provides a carrier wave eliminating method based on automatic tuning, which eliminates the target carrier wave signal by using the carrier wave eliminating system based on automatic tuning.
By using the carrier wave eliminating system and method based on automatic tuning, the function of automatically tuning and counteracting carrier wave signals is realized by adopting the passive device and the preset round inspection algorithm, the modulated signals after eliminating the carrier wave signals are obtained, the influence of introducing extra noise on the system can be avoided, and the system can be suitable for RFID systems with various frequency bands.
To the accomplishment of the foregoing and related ends, one or more aspects of the invention comprise the features hereinafter fully described. The following description and the annexed drawings set forth in detail certain illustrative aspects of the invention. These aspects are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Furthermore, the invention is intended to include all such aspects and their equivalents.
Drawings
Other objects and attainments together with a more complete understanding of the invention will become apparent and appreciated by referring to the following description taken in conjunction with the accompanying drawings. In the drawings:
fig. 1 is a schematic diagram of an auto-tune based carrier cancellation system according to an embodiment of the present invention;
Fig. 2 is a flow chart of a round robin algorithm according to an embodiment of the present invention.
Detailed Description
In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more embodiments. It may be evident, however, that such embodiment(s) may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing one or more embodiments.
As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless expressly stated otherwise, as understood by those skilled in the art. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that the term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
At present, in the scheme for overcoming carrier signal interference, two radio frequency paths, namely a linear radio frequency path and a nonlinear amplitude limiting radio frequency path, are arranged at the receiving front end, signals on the two paths are subtracted, a useful tag signal is reserved, and leakage signals are counteracted, but the scheme has the defects that the amplitude of an input signal and an output signal is required to be detected, then the gain of the nonlinear amplitude limiting path is adjusted through a digital algorithm controlled by an FPGA, so that the amplitude and the phase of the output signal are identical to the amplitude and the phase of the linear path carrier leakage signal, and the phase of the output signal are subtracted at the output end, so that carrier leakage signal counteraction is realized, and the counteraction effect of the method is influenced by the matching degree of the phase and the amplitude of the two paths, so that the control algorithm is complex, and extra noise is additionally introduced.
The other is realized by eliminating a negative feedback loop through carrier leakage, a carrier signal coupled out from the front end generates a reverse signal through an amplifier and a phase shifter to offset the carrier, but most of the scheme adopts an active device, so that unnecessary noise can be introduced, the phase shifter is difficult to realize a wide frequency band, the frequency coverage rate is very narrow, the requirement of universality cannot be realized, and the adjustable amplifier and the adjustable phase shifter are required to be adjusted simultaneously, so that the control aspect is relatively complex.
Accordingly, the present invention provides an auto-tuning based carrier cancellation system and method, and detailed description of the auto-tuning based carrier cancellation system and method will be given below with reference to the accompanying drawings.
Fig. 1 shows the principle of an auto-tune based carrier cancellation system according to an embodiment of the invention, and fig. 2 shows a schematic flow of a round robin algorithm according to an embodiment of the invention.
The carrier cancellation system based on automatic tuning in the embodiment of the invention comprises an orthogonal phase splitter, an adder, an output circuit connected with the adder, and a first circuit and a second circuit arranged between the orthogonal phase splitter and the adder, wherein a carrier signal of a radio frequency end to be processed is input into a coupling carrier input end of the orthogonal phase splitter, two paths of signals are formed after passing through the orthogonal phase splitter, then the two paths of signals are respectively input into the first circuit and the second circuit for processing respectively, the output signals processed by the first circuit and the second circuit are subjected to combining processing by the adder and output to the output circuit, and the combined signals and initial signals are subjected to subtracting and round-robin processing by the output circuit and a preset round-robin algorithm to finally obtain a modulation signal after the carrier signal is cancelled, wherein the initial signals comprise the carrier signal and the corresponding modulation signal, and the carrier signal can be effectively cancelled after being processed by the output circuit, so that the high-quality modulation signal is obtained.
The RFID reader-writer can emit a carrier signal, the carrier signal is emitted out through an antenna to provide energy for a tag, after the tag obtains the energy, a modulating signal of the tag can be loaded and reflected back to the RFID reader-writer, a radio frequency signal output by the RFID reader-writer is coupled to a coupling carrier input end through a coupler on the right side, and then the coupling carrier input end is used as a quadrature phase splitter through a 90-degree bridge to generate two paths of signals with a limit difference of 90 degrees, and the signals are respectively processed through a first circuit and a second circuit.
The first circuit further comprises a first balun converter, a first switch switcher, a second balun converter and a first numerical control attenuator which are sequentially connected, wherein one circuit processed by the quadrature phase splitter firstly performs balanced and unbalanced conversion through the first balun converter, then performs phase inversion on signals subjected to balanced and unbalanced conversion through the first switch switcher, further performs balanced and unbalanced conversion on the signals subjected to phase inversion through the second balun converter, and finally performs amplitude and phase regulation on signals output by the second balun converter through the first numerical control attenuator.
The second circuit comprises a third balun converter, a second switch switcher, a fourth balun converter and a second digital attenuator which are sequentially connected, wherein the other circuit processed by the quadrature phase splitter firstly performs balanced and unbalanced conversion through the third balun converter, then performs phase inversion on signals subjected to balanced and unbalanced conversion through the second switch switcher, further performs balanced and unbalanced conversion on the signals subjected to phase inversion through the fourth balun converter, and finally performs amplitude and phase regulation on signals output by the fourth balun converter through the second digital attenuator.
Specifically, the phase difference between two paths of signals formed through the quadrature phase splitter is 90 degrees, after the two paths of signals are processed by the first circuit and the second circuit, whether the finally output signals are forward or reverse can be determined through a subsequent round inspection algorithm, so that the optimal combination state is found out, and the carrier signals are effectively eliminated.
In a specific embodiment of the present invention, the output circuit further includes a combiner and an amplifier connected in sequence, the initial signal and the combined signal are both input into the combiner, the combined signal and the initial signal are subtracted by the combiner, so that only the modulation signal is retained, and the modulation signal output by the combiner is amplified and output by the amplifier. However, in the practical application process, the carrier signal cannot be completely cancelled, so that the subsequent amplifier, coupler, detector, MCU (Microcontroller Unit, micro control unit) and the like can cooperate to perform round robin algorithm processing so as to perform fine adjustment on the amplitude and phase of the signal, thereby weakening the carrier signal as much as possible and finding an optimal scheme.
The carrier cancellation system based on automatic tuning further comprises a coupler connected with the amplifier, and a detector and an MCU sequentially connected with the coupler, wherein the MCU can control states of a first circuit and a second circuit according to voltage values of the detector, the states of the first circuit comprise a switching state of a first switch switcher and an attenuation value of a first numerical control attenuator, and the states of the second circuit comprise a switching state of a second switch switcher and an attenuation value of a second numerical control attenuator.
The preset round inspection algorithm in the process of determining the states of the first circuit and the second circuit comprises the steps of controlling the first switch switcher and the second switch switcher to overturn phases of signals in the corresponding circuits through the MCU so that phases of carrier signals and initial signals are opposite and offset, monitoring voltage values of the detectors, judging that the phases meet opposite relations when the voltage values are minimum, and locking the switch states of the first switch switcher and the second switch switcher. And monitoring the voltage value of the detector through the MCU, adjusting the attenuation values of the first numerical control attenuator and the second numerical control attenuator, and locking the attenuation values of the first numerical control attenuator and the second numerical control attenuator and fixedly setting when the voltage value is the minimum value.
As a specific example, when the input signal of the coupled carrier input terminal is Acosx, after the processing of the 90 ° quadrature phase splitter, the two paths of signals are Acosx and Acos (x-90 °) =sinx, where a represents a coefficient and x represents an argument. Then, the two paths of signals are respectively subjected to power distribution through a 180-degree balance-to-unbalance balun converter to generate two outputs with equal amplitude but 180 degrees phase difference, the two signals are turned over in phase through a switch switcher, and finally the amplitude and the phase of the signals are controlled through a numerical control attenuator to be adjusted.
Specifically, two paths of signals Acosx and Asinx generated after the quadrature phase splitter processing are subjected to balun switching, the output signals corresponding to a signal Acosx are Acosx and Acos (x-180) = -cosx, the output signals corresponding to a signal Asinx are Asinx and Asin (x-180) = -sinx, one path of signals is subjected to switching through a combination of a switch and a digital attenuator, the output signals are U1cosx or-U1 cosx, the other path of signals is subjected to switching through a combination of a switch and a digital attenuator, the output signals are U2sinx or-U2 sinx, and U1 and U2 respectively represent the amplitudes of the corresponding signals, so that whether the specific output signals are forward or reverse can be determined through a round robin algorithm.
Further, the signals after the combination are combined by the adder, and the combined signals are converted by the trigonometric function, that is, the combined signals are: Wherein, the method comprises the steps of, wherein, Θ represents the phase angle of the combined signal.
Then, the combiner, namely the 90-degree bridge, is used for subtracting the initial signals of the input ends of the combined signal and the received reverse signal, and only the modulation signals are reserved, so that the carrier signals are eliminated. At this time, the obtained modulation signal is: K represents an independent variable of the modulation signal, bcosx is a signal returned by antenna coupling, the signal is input into the combiner through a return signal input terminal, b represents the amplitude of the signal, and R represents the amplitude of the combined signal. It is known that in practical situations the carrier signal cannot be completely cancelled out, but is only attenuated as much as possible. Therefore, the power amplifier, the coupler and the detector in the output circuit can be matched with the MCU to carry out round-robin scheduling, so that the amplitude and the phase of signals in the circuit are finely adjusted, and the optimal combination state is determined.
Firstly, the MCU detects the voltage of the output power of the non-offset carrier wave as an initial calibration value V1 through the detector, namely, the voltage is set as the initial calibration value V1 when no return input signal is generated, then the return input signal is loaded, the MCU controls the switch to overturn the signal phase in the corresponding circuit, so that the coupled carrier wave signal and the return input signal are opposite in phase and offset, namely. Traversing the voltage values detected under various states by a round robin algorithm, comparing the voltage values with an initial value V1, and finding out the minimum value even ifWhen the voltage value is the minimum value, the phase can be judged to meet the opposite relation, the switching states of the two switching devices are fixed, the value is taken as a calibration value V2, the corresponding numerical control attenuator is adjusted, the voltage value of the detector is monitored to be fine-tuned, the voltage value V3 in various attenuation states is traversed through a round-robin algorithm, the optimal numerical control attenuation value is found out, and the fixed setting is realized, namely the amplitude R=b, so that complete carrier cancellation is achieved.
Correspondingly to the carrier cancellation system based on the automatic tuning, the invention also provides a carrier cancellation method based on the automatic tuning, and the carrier cancellation system based on the automatic tuning is used for canceling the target carrier signal.
It should be noted that, the embodiments of the carrier cancellation method based on auto-tuning may refer to the descriptions in the embodiments of the carrier cancellation system based on auto-tuning, which are not described herein.
According to the carrier cancellation system and the carrier cancellation method based on automatic tuning, disclosed by the invention, the passive device and the preset round-robin algorithm are adopted, the additional noise brought by using the phase shifter is not worried, the function of automatically tuning and canceling the carrier signal can be realized, the modulated signal after the carrier signal is cancelled is obtained, the influence of the additional noise on the system is avoided, the control algorithm is simple, and the carrier cancellation system and the carrier cancellation method based on automatic tuning are applicable to RFID systems in various frequency bands.
The auto-tuning based carrier cancellation system and method according to the present invention are described above by way of example with reference to the accompanying drawings. It will be appreciated by those skilled in the art that various modifications may be made to the auto-tune based carrier cancellation system and method set forth in the foregoing invention without departing from the spirit of the invention. Accordingly, the scope of the invention should be determined from the following claims.
Claims (10)
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| CN202510142450.2A CN119602816A (en) | 2025-02-10 | 2025-02-10 | Carrier elimination system and method based on automatic tuning |
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| CN202510142450.2A CN119602816A (en) | 2025-02-10 | 2025-02-10 | Carrier elimination system and method based on automatic tuning |
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|---|---|---|---|---|
| EP1983710A1 (en) * | 2006-02-08 | 2008-10-22 | Pioneer Corporation | Carrier reproducing device, and demodulating device |
| CN102222246A (en) * | 2011-06-25 | 2011-10-19 | 深圳市远望谷信息技术股份有限公司 | Carrier inhibiting method for radio frequency identification reader-writer and radio frequency device |
| CN208938118U (en) * | 2018-12-17 | 2019-06-04 | 上海沿芯微电子科技有限公司 | A kind of passive self-interference cancellation circuit of RFID reader |
| CN110969034A (en) * | 2019-11-04 | 2020-04-07 | 锐捷网络股份有限公司 | Carrier cancellation circuit and RFID reader-writer |
| CN115913852A (en) * | 2022-10-26 | 2023-04-04 | 西安空间无线电技术研究所 | Novel high carrier suppression four-phase balanced modulator |
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2025
- 2025-02-10 CN CN202510142450.2A patent/CN119602816A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1983710A1 (en) * | 2006-02-08 | 2008-10-22 | Pioneer Corporation | Carrier reproducing device, and demodulating device |
| CN102222246A (en) * | 2011-06-25 | 2011-10-19 | 深圳市远望谷信息技术股份有限公司 | Carrier inhibiting method for radio frequency identification reader-writer and radio frequency device |
| CN208938118U (en) * | 2018-12-17 | 2019-06-04 | 上海沿芯微电子科技有限公司 | A kind of passive self-interference cancellation circuit of RFID reader |
| CN110969034A (en) * | 2019-11-04 | 2020-04-07 | 锐捷网络股份有限公司 | Carrier cancellation circuit and RFID reader-writer |
| CN115913852A (en) * | 2022-10-26 | 2023-04-04 | 西安空间无线电技术研究所 | Novel high carrier suppression four-phase balanced modulator |
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