CN113014273A

CN113014273A - Self-adaptive anti-interference method and self-adaptive anti-interference device

Info

Publication number: CN113014273A
Application number: CN202110083379.7A
Authority: CN
Inventors: 李世信; 黄西月; 柳晓见; 戚国刚
Original assignee: Hytera Communications Corp Ltd
Current assignee: Hytera Communications Corp Ltd
Priority date: 2021-01-21
Filing date: 2021-01-21
Publication date: 2021-06-22
Anticipated expiration: 2041-01-21
Also published as: CN113014273B

Abstract

The application discloses a self-adaptive anti-interference method and a self-adaptive anti-interference device, wherein the method comprises the steps of receiving a radio frequency signal; selecting one local oscillation frequency from a preset local oscillation frequency table as the frequency of a local oscillation 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 intensity of an interference signal, wherein the interference signal comprises a blocking interference signal and an adjacent channel interference signal; judging whether the signal intensity of the interference signal meets a preset condition or not; and if the signal intensity of the interference signal does not meet the preset condition, selecting another local oscillator frequency from the preset local oscillator frequency table as the frequency of the local oscillator signal, returning to execute the step of processing the local oscillator signal and the received radio frequency signal to obtain the intermediate frequency signal until the signal intensity of the interference signal meets the preset condition or all local oscillator frequencies in the preset local oscillator frequency table are selected. Through the mode, the anti-interference capacity can be improved.

Description

Self-adaptive anti-interference method and self-adaptive anti-interference device

Technical Field

The present application relates to the field of communications technologies, and in particular, to an adaptive anti-interference method and an adaptive anti-interference apparatus.

Background

The zero intermediate frequency receiver has the advantage of high integration, is more and more widely applied to communication products, and has obvious defects. Due to the existence of the strong interference self-mixing phenomenon, the zero intermediate frequency anti-blocking capability is poor. Although the existing low-intermediate frequency receiver scheme can effectively solve the problems, the interference resistance of adjacent channels is sacrificed.

In a long-term research and development process, the inventor of the present application finds that an algorithm for interference detection is complex at present, and occupies a large amount of Digital Signal Processor (DSP) resources. When the circuit has blocking interference and adjacent channel interference, the interference signal processing basically cannot achieve the anti-interference effect, and the useful signal is affected.

Disclosure of Invention

The technical problem mainly solved by the application is to provide a self-adaptive anti-interference method and a self-adaptive anti-interference device, and the anti-interference capability can be improved.

In order to solve the technical problem, the application adopts a technical scheme that: an adaptive anti-interference method is provided, which comprises the following steps: receiving a radio frequency signal; selecting one local oscillation frequency from a preset local oscillation frequency table as the frequency of a local oscillation 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 intensity of an interference signal, wherein the interference signal comprises a blocking interference signal and an adjacent channel interference signal; judging whether the signal intensity of the interference signal meets a preset condition or not; and if the signal intensity of the interference signal does not meet the preset condition, selecting another local oscillator frequency from the preset local oscillator frequency table as the frequency of the local oscillator signal, returning to execute the step of processing the local oscillator signal and the received radio frequency signal to obtain the intermediate frequency signal until the signal intensity of the interference signal meets the preset condition or all local oscillator frequencies in the preset local oscillator frequency table are selected.

In one implementation, the step of selecting one local oscillation frequency from a preset local oscillation frequency table as the frequency of the local oscillation signal includes: and selecting the maximum local oscillation frequency in the preset local oscillation frequency table as the frequency of the local oscillation signal.

In another implementation, the step of processing the local oscillator signal and the radio frequency signal to obtain the intermediate frequency signal includes: and mixing the local oscillator signal with the radio frequency signal to generate an 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; carrying out blocking interference detection on the filtered radio frequency signal to obtain the signal intensity of the blocking interference signal; and carrying out adjacent channel interference detection on the intermediate frequency signal to obtain the signal intensity of the adjacent channel interference signal.

In another implementation, 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; and carrying out adjacent channel interference detection on the channel where the digital signal is located to obtain the signal intensity of the adjacent channel interference signal.

In another implementation, 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 determining whether the signal strength of the interference signal satisfies the preset condition includes: judging whether the difference value between the signal intensity of the right adjacent channel interference signal and the signal intensity of the useful signal is greater than a right adjacent channel interference threshold or not; if the signal intensity of the right adjacent channel interference signal is greater than the right adjacent channel interference threshold, judging whether to adjust the frequency of the local oscillator signal or not by utilizing the signal intensity of the left adjacent channel interference signal, the signal intensity of the right adjacent channel interference signal, the signal intensity of the useful signal and the signal intensity of the blocking interference signal; and if the right adjacent channel interference signal is smaller than the right adjacent channel interference threshold, the frequency of the local oscillation signal is not adjusted.

In another implementation manner, the step of determining whether to adjust the frequency of the local oscillator signal by using 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 includes: judging whether the difference value between the signal intensity of the left adjacent channel interference signal and the signal intensity of the useful signal is larger than a left adjacent channel interference threshold or not; if the difference between the signal intensity of the left adjacent channel interference signal and the signal intensity of the useful signal is larger than the left adjacent channel interference threshold, calculating the difference between the signal intensity of the blocking interference signal and the signal intensity of the useful signal, and judging whether to adjust the frequency of the local oscillator signal or not by utilizing the difference between the signal intensity of the blocking interference signal and the signal intensity of the useful signal, the signal intensity of the left adjacent channel interference signal and the signal intensity of the right adjacent channel interference signal; and if the difference value between the signal intensity of the left adjacent channel interference signal and the signal intensity 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.

In another implementation manner, the preset local oscillation frequency table includes multiple groups of local oscillation frequencies, each group of local oscillation frequencies includes a high local oscillation frequency and a low local oscillation frequency, each group of local oscillation frequencies corresponds to a blocking interference threshold in the preset blocking suppression table one to one, and the step of determining whether to adjust the frequency of the local oscillation signal includes the steps of using a difference between the signal intensity of the blocking interference signal and the signal intensity of the useful signal, the signal intensity of the left adjacent channel interference signal and the signal intensity of the right adjacent channel interference signal: judging whether the difference value between the signal intensity of the blocking interference signal and the signal intensity of the useful signal is larger than the next blocking interference threshold of the current blocking interference threshold or not; if the difference value between the signal intensity of the blocking interference signal and the signal intensity of the useful signal is greater than the next blocking interference threshold, judging whether the signal intensity of the right adjacent channel interference signal is greater than the signal intensity of the left adjacent channel interference signal; if the signal intensity of the right adjacent channel interference signal is greater than that of the left adjacent channel interference signal, adjusting the frequency of the local oscillation signal to be a low local oscillation frequency corresponding to the current blocking interference threshold; if the signal intensity of the right adjacent channel interference signal is less than or equal to the signal intensity of the left adjacent channel interference signal, adjusting the frequency of the local oscillation signal to be a high local oscillation frequency corresponding to the current blocking interference threshold; and 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, taking the next blocking interference threshold as the current blocking interference threshold, and returning 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 or not 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 a preset blocking interference threshold table.

In order to solve the above technical problem, another technical solution adopted by the present application is: the self-adaptive anti-jamming device comprises a processing circuit and a detection circuit, wherein the detection circuit is connected with the processing circuit. The processing circuit is used for receiving radio frequency signals; selecting one local oscillation frequency from a preset local oscillation frequency table as the frequency of a local oscillation signal; processing the local oscillator signal and the radio frequency signal to obtain an intermediate frequency signal; the detection circuit is used for carrying out interference detection on the radio frequency signal and the intermediate frequency signal to obtain the signal intensity of an interference signal, wherein the interference signal comprises a blocking interference signal and an adjacent channel interference signal; the detection circuit is also used for judging whether the signal intensity of the interference signal meets a preset condition or not; and if the signal intensity of the interference signal does not meet the preset condition, selecting another local oscillator frequency from the preset local oscillator frequency table as the frequency of the local oscillator signal, returning to execute the processing of the local oscillator signal and the radio frequency signal to obtain the intermediate frequency signal until the signal intensity of the interference signal meets the preset condition or all the local oscillator frequencies in the preset local oscillator frequency table are selected.

In order to solve the above technical problem, another technical solution adopted by the present application is: there is provided a receiver comprising an antenna and an adaptive interference rejection unit according to the above solution.

The beneficial effect of this application is: unlike the prior art, the present application can receive radio frequency signals; then selecting one local oscillation frequency from a preset local oscillation frequency table as the frequency of a local oscillation signal; then processing the local oscillator signal and the radio frequency signal to obtain an intermediate frequency signal; then, carrying out blocking interference detection on the radio frequency signal, and carrying out adjacent channel interference detection on the intermediate frequency signal; judging whether the current interference signal strength meets a preset condition or not by using the signal strength of the blocking interference signal and the signal strength of the adjacent channel interference signal, if not, adjusting the frequency of the local oscillator signal to adjust the frequency of the intermediate frequency signal, then judging whether the interference signal strength corresponding to the currently newly generated intermediate frequency signal meets the preset condition or not, if not, continuously adjusting the frequency of the local oscillator signal, and if so, ending the adjustment process; because the frequency of the intermediate frequency signal is higher, the phenomenon of signal self-mixing is less obvious, the anti-blocking interference ability is stronger, but the influence of the adjacent channel interference is larger, the anti-adjacent channel interference ability is poor, the frequency of the local oscillator signal is adjusted, so that the frequency of the intermediate frequency signal is changed, the anti-adjacent channel interference and the anti-blocking interference can be balanced, the signal intensity of the blocking interference signal and the signal intensity of the adjacent channel interference signal both meet the preset condition under a certain intermediate frequency, the anti-adjacent channel interference ability and the anti-blocking interference ability both meet the requirements, and the anti-interference ability of the receiver is improved.

Drawings

FIG. 1 is a schematic structural diagram of an embodiment of an adaptive immunity device provided in the present application;

FIG. 2 is a schematic structural diagram of another embodiment of an adaptive immunity device provided in the present application;

FIG. 3 is a flowchart illustrating an embodiment of an adaptive anti-jamming method provided in the present application;

FIG. 4 is a schematic flowchart of another embodiment of an adaptive anti-jamming method provided in the present application;

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

FIG. 6 is a schematic flow chart 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;

FIG. 8 is a schematic diagram of an anti-tamper test in an embodiment of an adaptive anti-tamper method provided herein;

fig. 9 is a schematic structural diagram of an embodiment of a receiver provided in the present application.

Detailed Description

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, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Referring to fig. 1, fig. 1 is a schematic structural diagram of an embodiment of an adaptive anti-jamming device 10 provided in the present application, which includes a processing circuit 11 and a detection circuit 13 connected to each other.

The processing circuit 11 is used for receiving radio frequency signals; selecting one local oscillation frequency from a preset local oscillation frequency table as the frequency of a local oscillation 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 a signal strength of an interference signal, where the interference signal includes a blocking interference signal and an adjacent channel interference signal.

The processing circuit 11 is further configured to determine whether the signal strength of the interference signal satisfies a preset condition; and if the signal intensity of the interference signal does not meet the preset condition, selecting another local oscillator frequency from the preset local oscillator frequency table as the frequency of the local oscillator signal, returning to execute the processing of the local oscillator signal and the radio frequency signal to obtain the intermediate frequency signal until the signal intensity of the interference signal meets the preset condition or all the local oscillator frequencies in the preset local oscillator frequency table are selected.

Referring to fig. 2, fig. 2 is a schematic structural diagram of another embodiment of the adaptive immunity device 10 provided in the present application, which includes a processing circuit 11 and a detection circuit 13.

The processing circuit 11 comprises 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 rf receiver 111 is configured to receive an rf signal; the low pass filter 112 is connected to the rf receiver 111, and is configured to pass signals of useful frequencies in the received rf signals, and simultaneously suppress signals of non-useful frequencies, i.e. a desired frequency point is set, signals lower than the desired frequency point are allowed to pass, and signals higher than the desired frequency point are filtered to eliminate a part of interference signals.

The band-pass filter 113 is connected to the low-pass filter 112, and is used for band-pass filtering the signal output from the low-pass filter 112, that is, setting a frequency range, allowing the signal falling within the frequency range to pass through, and blocking or attenuating the signal falling outside the frequency range. Part of the interference signal can be eliminated by the filtering action of the low-pass filter 112 and the band-pass filter 113.

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

The quadrature mixer 115 is connected to the local oscillator 114, and is configured to mix the local oscillator signal output by the local oscillator 114 with the filtered radio frequency signal output by the band-pass filter 113 to generate an intermediate frequency signal.

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

Referring 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, and the controller 117 is configured to control the local oscillator 114, the detection circuit 13 and the digital signal processor 15.

The digital signal processor 15 includes a channel filter 151 and a demodulator 152; the channel filter 151 is configured to filter the digital signal, so that the signal in a certain frequency range completely passes through the channel filter, and generate a useful digital signal, and filter a non-useful signal outside the certain frequency range; the demodulator 152 is configured to restore the useful digital signal to an original signal, i.e., a baseband signal, i.e., the digital signal after analog-to-digital conversion is filtered to generate the useful digital signal, and then generate the baseband signal through demodulation.

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

The blocking detector 131 is connected to the band-pass filter 113 and the controller 117, and is configured to detect a signal strength of the blocking interference signal; specifically, the blocking detector 131 may sample the filtered radio frequency signal, and perform blocking interference detection on the sampled radio frequency signal, so as to obtain the signal strength of the blocking interference signal.

The adjacent channel detector 132 is connected to the controller 117, and is configured to detect the signal strength of an adjacent channel interference signal, where the adjacent channel interference signal includes a left adjacent channel interference signal and a right adjacent channel interference signal; specifically, the intermediate frequency signal may be subjected to analog-to-digital conversion to obtain a digital signal, and adjacent channel interference detection may be performed on a channel where the digital signal is located, so as to obtain a signal intensity of the left adjacent channel interference signal and a signal intensity of the right adjacent channel interference signal.

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

The embodiment provides a self-adaptive anti-interference device, which comprises a processing circuit, a detection circuit and a digital signal processor, wherein the processing circuit carries out frequency mixing on a radio frequency signal and a local oscillator signal to obtain an intermediate frequency signal, and carries out analog-to-digital conversion on the intermediate frequency signal to obtain a digital signal; the digital signal processor carries out filtering processing on the digital signal obtained by carrying out analog-to-digital conversion; the detection circuit carries out blocking interference detection, adjacent channel interference detection and useful signal detection, the blocking detector can be used for sampling the radio frequency signal after filtering processing, and the blocking interference detection is carried out on the radio frequency signal obtained by sampling to obtain the signal intensity of the blocking interference signal; performing adjacent channel interference detection on a channel where a digital signal generated after analog-to-digital conversion is located by using an adjacent channel detector to obtain the signal intensity of a right adjacent channel interference signal and the signal intensity of a left adjacent channel interference signal; carrying out signal intensity detection on the filtered digital signal by using a signal intensity detector to obtain the signal intensity of a useful signal; by measuring the interference signal, the processing circuit can judge whether the current local oscillation frequency needs to be adjusted or not, so that the most appropriate local oscillation frequency is selected to generate a useful signal, the intermediate frequency signal after frequency mixing can adapt to the conditions that the interference of the left and right adjacent channels exists simultaneously, the better inhibition effect of the interference of the two adjacent channels and the interference of the blocking can be obtained, and the interference resistance can be improved.

Referring to fig. 1 and fig. 3, fig. 3 is a schematic flowchart illustrating an embodiment of an adaptive anti-interference method provided in the present application, where the method specifically includes the following steps:

step 31: a radio frequency signal is received.

The processing circuit 11 may receive the radio frequency signal and perform filtering processing on the received radio frequency signal, so that the radio frequency signal in a certain frequency range passes through, and the radio frequency signal outside the certain frequency range is blocked or attenuated, so as to eliminate or reduce the influence of the interference signal.

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

Step 32: and selecting one local oscillation frequency from the preset local oscillation frequency table as the frequency of the local oscillation signal.

The processing circuit 11 stores a preset local oscillation frequency table, where the preset local oscillation frequency table includes multiple groups of local oscillation frequencies, each group of local oscillation frequencies includes a high local oscillation frequency and a low local oscillation frequency, the frequencies (intermediate frequency) of intermediate frequency signals corresponding to the high local oscillation frequency and the low local oscillation frequency are the same, the high local oscillation frequency is the sum of the intermediate frequency and the frequency of a radio frequency signal, the low local oscillation frequency is the difference between the frequencies of the radio frequency signal and the intermediate frequency, and the multiple groups of local oscillation frequencies in the preset local oscillation frequency table are arranged in order from large to small. It can be understood that the preset local oscillator frequency table may be set according to an application scenario where the processing circuit 11 is located, and the local oscillator frequencies in the corresponding preset local oscillator frequency table may be different in different application scenarios.

In this embodiment, the processing circuit 11 may select the maximum local oscillation frequency in the preset local oscillation frequency table from the preset local oscillation frequency table as the frequency of the initial local oscillation signal. The processing circuit 11 may sequentially select local oscillation frequencies from a preset local oscillation frequency table according to the interference condition of the application scene, and switch the local oscillation frequencies in order from large to small until a suitable local oscillation frequency is obtained.

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

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

Step 34: and carrying out interference detection on the radio frequency signal and the intermediate frequency signal to obtain the signal intensity of the interference signal.

The interference signal comprises a blocking interference signal and an adjacent channel interference signal, the radio frequency signal after filtering processing is sampled, the detection circuit 13 is used for carrying out blocking interference detection on the radio frequency signal obtained by sampling, so that the signal intensity of the blocking interference signal is obtained, and the signal intensity of the blocking interference signal can be 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: and judging whether the signal intensity of the interference signal meets a preset condition or not.

The processing circuit 11 may process the signal strength of the received 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: and if the signal intensity of the interference signal does not meet the preset condition, selecting another local oscillator frequency from the preset local oscillator frequency table as the frequency of the local oscillator signal.

If the signal strength of the interference signal does not satisfy the preset condition, the processing circuit 11 is required to change the frequency of the output local oscillation signal, that is, the processing circuit 11 selects the next frequency of the current frequency from the preset local oscillation frequency table as the frequency of the local oscillation signal, and returns to execute step 33 until the signal strength of the interference signal satisfies the preset condition or all the local oscillation frequencies in the preset local oscillation frequency table are selected. If the signal strength of the interference signal satisfies the preset condition, the processing circuit 11 does not adjust the local oscillator signal frequency.

In this embodiment, whether the frequency of the output local oscillator signal is changed or not is determined by detecting the signal intensity of the interference signal at the current local oscillator frequency, so as to change the size of the intermediate frequency signal, so that the signal intensity of the interference signal corresponding to the adjusted local oscillator frequency meets the preset condition. Through the frequency adjustment to the local oscillator signal, the frequency of the intermediate frequency signal changes, so that the signal intensity of the blocking interference signal and the signal intensity of the adjacent channel interference signal both meet the preset condition, and the anti-interference capability when the adjacent channel interference and the blocking interference exist simultaneously can be improved.

Referring to fig. 2 and fig. 4, fig. 4 is a schematic flowchart illustrating a flow of another embodiment of the adaptive anti-jamming method provided in the present application, where the adaptive anti-jamming method specifically includes the following steps:

step 401: a radio frequency signal is received.

The rf receiver 111 may receive an rf signal and input the received rf signal to the low pass filter 112.

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

In order to eliminate or reduce the influence of interference signals, the signals after filtering processing are used as radio frequency signals mixed with local oscillator signals; specifically, after the received rf signal passes through the low pass filter 112 and the band pass filter 113, the rf signal with a frequency falling within a certain frequency range passes through, and the low pass filter 112 and the band pass filter 113 may block or attenuate the rf signal outside the certain frequency range from passing through, so as to eliminate a part of the interference signal.

Step 403: and carrying out blocking interference detection on the filtered radio frequency signal to obtain the signal intensity of the blocking interference signal.

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

Step 404: and selecting the maximum local oscillation frequency in the preset local oscillation frequency table as the frequency of the local oscillation signal.

A preset local oscillator frequency table may be preset, where the preset local oscillator frequency table includes multiple groups of local oscillator frequencies, and the local oscillator frequencies in the preset local oscillator frequency table may be specifically set according to an application scenario in which 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, and switches the frequency of the local oscillator 114 until the suitable local oscillator frequency is obtained, and stops the frequency switching.

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

The quadrature mixer 115 may mix the filtered rf signal with the local oscillator signal output by the local oscillator 114 to generate an intermediate frequency signal.

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

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

Step 407: and processing the digital signal to generate a useful signal, and detecting the signal intensity to obtain the signal intensity of the useful signal.

In order to eliminate or reduce the interference caused by the non-useful signal, the digital signal after the filtering process can be used as the digital signal input to the signal strength detector 133 to obtain the signal strength of the useful signal; specifically, after the digital signal obtained by analog-to-digital conversion passes through the channel filter 151, the digital signal whose frequency falls within a certain frequency range passes through, and the channel filter 151 may block or attenuate the digital signal outside the certain frequency range from passing through, so as to eliminate a part of the interference signal.

Step 408: and judging whether the difference value between the signal intensity of the right adjacent channel interference signal and the signal intensity of the useful signal is larger than a right adjacent channel interference threshold or not.

The right adjacent channel interference threshold may be preset, and the setting of the right adjacent channel interference threshold may include the signal strength of the maximum allowed right adjacent channel interference signal, the ratio of the signal strength of the maximum allowed right adjacent channel interference signal to the signal strength of the useful signal, or the difference between the signal strength of the maximum allowed right adjacent channel interference signal and the signal strength of the useful signal. The following describes the technical solution of the present embodiment by using the difference between the maximum allowed signal strength of the right adjacent channel interference signal and the signal strength of the useful signal as the right adjacent channel interference threshold, but is not limited thereto.

The controller 117 calculates a difference between the signal strength of the received right adjacent channel interference signal and the signal strength of the desired signal, and compares the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the desired signal with a right adjacent channel interference threshold to determine whether to perform frequency adjustment of the local oscillation signal; if the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the useful signal is smaller than the right adjacent channel interference threshold, step 409 is executed, otherwise step 410 is executed.

Step 409: and if the difference value between the signal intensity of the right adjacent channel interference signal and the signal intensity of the useful signal is less than or equal to the right adjacent channel interference threshold, the frequency of the local oscillation signal is not adjusted.

If the difference value between the signal intensity of the right adjacent channel interference signal and the signal intensity of the useful signal is smaller than the right adjacent channel interference threshold, the influence of the current right adjacent channel interference on the intermediate frequency signal is small, at the moment, the frequency of the intermediate frequency signal does not need to be adjusted, and the local frequency is kept to be the high local frequency under the current group of local frequency.

Step 410: and if the difference value between the signal intensity of the right adjacent channel interference signal and the signal intensity of the useful signal is greater than the right adjacent channel interference threshold, judging whether to adjust the frequency of the local oscillator signal or not by utilizing the signal intensity of the left adjacent channel interference signal, the signal intensity of the right adjacent channel interference signal, the signal intensity of the useful signal and the signal intensity of the blocking interference 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 influence of the current right adjacent channel interference on the intermediate frequency signal is large and exceeds the current allowable maximum limit, and at this time, whether the intermediate frequency needs to be adjusted or not can be judged by using the signal strength of the right adjacent channel interference signal, the signal strength of the left adjacent channel interference signal, the signal strength of the useful signal and the signal strength of the blocking interference signal, that is, whether the frequency of the local oscillator signal needs to be adjusted or not needs to be comprehensively judged by combining the left adjacent channel interference condition and the blocking interference condition.

In a specific embodiment, the scheme shown in fig. 5 may be adopted to perform the processing to determine whether the frequency of the local oscillator signal needs to be adjusted, specifically including the following steps:

step 51: and judging whether the difference value between the signal intensity of the left adjacent channel interference signal and the signal intensity of the useful signal is larger than a left adjacent channel interference threshold or not.

The left-adjacent channel interference threshold may be preset, and the setting of the left-adjacent channel interference threshold may include the maximum allowed signal strength of the left-adjacent channel interference signal, the ratio of the maximum allowed signal strength of the left-adjacent channel interference signal to the signal strength of the useful signal, or the difference between the maximum allowed signal strength of the left-adjacent channel interference signal and the signal strength of the useful signal. The following describes the technical solution of the present embodiment by using the difference between the maximum allowed signal strength of the left adjacent channel interference signal and the signal strength of the useful signal as the left adjacent channel interference threshold, but is not limited thereto.

The controller 117 calculates a difference between the signal strength of the received left adjacent channel interference signal and the signal strength of the useful signal, and compares the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the useful signal with a left adjacent channel interference threshold to determine whether to perform frequency adjustment of the local oscillation 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 executed, otherwise step 53 is executed.

Step 52: and if the difference value between the signal intensity of the left adjacent channel interference signal and the signal intensity 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 intensity of the left adjacent channel interference signal and the signal intensity of the useful signal is smaller than the left adjacent channel interference threshold, it indicates that the influence of the current left adjacent channel interference on the intermediate frequency signal is small, and at this moment, the frequency of the intermediate frequency signal does not need to be adjusted, and the local frequency is set to be the low local frequency under the current group of local frequency in the preset local frequency table.

Step 53: if the difference between the signal intensity of the left adjacent channel interference signal and the signal intensity of the useful signal is larger than the left adjacent channel interference threshold, calculating the difference between the signal intensity of the blocking interference signal and the signal intensity of the useful signal, and judging whether to adjust the frequency of the local oscillator signal by using the difference between the signal intensity of the blocking interference signal and the signal intensity of the useful signal, the signal intensity of the right adjacent channel interference signal and the signal intensity of the left adjacent channel interference 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 influence of the current left adjacent channel interference on the intermediate frequency signal is large and exceeds the current allowable maximum limit, and at this time, whether the frequency of the local oscillator signal needs to be adjusted or not can be judged by 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 right adjacent channel interference signal and the signal strength of the left adjacent channel interference signal, that is, whether the frequency of the local oscillator signal needs to be adjusted or not is comprehensively judged by combining the blocking interference condition, the signal strength of the useful signal, the left adjacent channel interference condition and the right adjacent channel interference condition.

Further, a preset blocking interference threshold table may be preset, the blocking interference thresholds in the preset blocking interference threshold table correspond to each group of local oscillator frequencies in the preset local oscillator frequency table one to one, and the blocking interference thresholds may be set to be a difference between a maximum allowable signal intensity of the blocking interference signal and a maximum allowable signal intensity of the useful signal. In this embodiment, the low-if receiver is used as an application scenario of the local oscillator 114 to set the preset local oscillator frequency table, and the blocking interference threshold table determined and set according to the preset local oscillator frequency table is used to describe the technical solution of this embodiment, but is not limited thereto.

The controller 117 calculates a difference between the signal strength of the received blocking interference signal and the signal strength of the useful signal to obtain a difference between the signal strength of the blocking interference signal and the signal strength of the useful signal, and determines whether the frequency of the local oscillator signal needs to be adjusted by 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 right adjacent channel interference signal, and the signal strength of the left adjacent channel interference signal.

In a specific embodiment, the scheme shown in fig. 6 may be adopted to perform processing to determine whether the frequency of the local oscillator signal needs to be adjusted, which specifically includes the following steps:

step 61: and judging whether the difference value between the signal strength of the blocking interference signal and the signal strength of the useful signal is larger than the next blocking interference threshold of the current blocking interference threshold.

Recording the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal as blocking interference; the frequency of the current local oscillation signal can be obtained, namely the current local oscillation frequency is assumed to be in the nth group of local oscillation frequency in the preset local oscillation frequency table; and acquiring an n +1 th blocking interference threshold from a preset blocking interference threshold table, and then judging whether the blocking interference corresponding to the nth group of local oscillator frequencies is greater than the n +1 th 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 executed, otherwise step 65 is executed.

Step 62: and if the difference value between the signal intensity of the blocking interference signal and the signal intensity of the useful signal is greater than the next blocking interference threshold, judging whether the signal intensity of the right adjacent channel interference signal is greater than the signal intensity of the left adjacent channel interference signal.

If the difference value between the signal intensity of the blocking interference signal and the signal intensity of the useful signal is larger than the next blocking interference threshold of the current blocking interference threshold, the better blocking interference resistance is shown under the current frequency, and the adjacent channel interference resistance is detected under the better blocking interference resistance, so that the adjacent channel interference resistance and the blocking interference resistance can be balanced, and the optimal bilateral adjacent channel interference suppression effect is obtained.

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 executed, otherwise step 64 is executed.

And step 63: and if the signal intensity of the right adjacent channel interference signal is greater than that of the left adjacent channel interference signal, adjusting the frequency of the local oscillator signal to be a low local oscillator frequency corresponding to the current blocking interference threshold.

If the signal strength of the right adjacent channel interference signal is greater than the signal strength of the left adjacent channel interference signal, which indicates that the interference on the left adjacent channel is small, the controller 117 may control the local oscillator 114 to adjust the local oscillator frequency, so as to adjust the frequency of the local oscillator signal to a low local oscillator frequency corresponding to the current blocking interference threshold.

Step 64: and if the signal intensity of the right adjacent channel interference signal is less than or equal to the signal intensity of the left adjacent channel interference signal, adjusting the frequency of the local oscillation signal to be a high local oscillation 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, which indicates that the interference on the right adjacent channel is small, the controller 117 may control the local oscillator 114 to adjust the local oscillator frequency, so as to adjust the local oscillator frequency to a high local oscillator frequency corresponding to the current blocking interference threshold.

Step 65: and if the difference value 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, taking the next blocking interference threshold as the current blocking interference threshold.

And when the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is smaller than or equal to the next blocking interference threshold, taking the next blocking interference threshold as the current blocking interference threshold, and returning to execute 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 larger than the next blocking interference threshold of the current blocking interference threshold, namely executing the step 61 until the difference between the signal strength of the blocking interference signal and the signal strength of the useful signal is smaller than or equal to the next blocking interference threshold, or the next blocking interference threshold is the last blocking interference threshold in a 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 under the current intermediate frequency does not meet the condition, and the anti-blocking interference capability is not better. At the moment, the new intermediate frequency can be obtained by adjusting the frequency of the local oscillator signal, so that the anti-blocking interference capability is better.

For example, when the current local oscillation frequency is in the nth group of local oscillation frequencies in the preset local oscillation frequency table and the blocking interference threshold corresponding to the nth group of local oscillation frequencies, n is set to be n +1, the frequency of the local oscillation signal in the (n + 1) th group of local oscillation frequencies is used as the frequency of the current local oscillation signal, the blocking interference threshold corresponding to the (n + 1) th group of local oscillation frequencies is used as the current blocking interference threshold, whether the difference between the signal intensity of the blocking interference signal and the signal intensity of the useful signal is greater than the next blocking interference threshold is continuously judged until the difference between the signal intensity of the blocking interference signal and the signal intensity of the useful signal meets the preset condition or the next blocking interference threshold is the last blocking interference threshold in the preset blocking interference threshold table, and the adjustment is stopped.

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

step 71: and judging whether the difference value between the signal strength of the blocking interference signal and the signal strength of the useful signal is larger than the next blocking interference threshold of the current blocking interference threshold.

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

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

Step 72: and if the difference between the signal strength of the jamming interference signal and the signal strength of the useful signal is greater than the next jamming interference threshold, judging whether the difference between the signal strength of the right adjacent channel jamming signal and the signal strength of the useful signal and the difference between the signal strength of the left adjacent channel jamming signal and the signal strength of the useful signal are both smaller than the adjacent channel jamming threshold.

When the difference value between the signal intensity of the blocking interference signal and the signal intensity of the useful signal is larger than the next blocking interference threshold of the current blocking interference threshold, the better blocking interference resistance is shown under the current frequency, and the adjacent channel interference resistance is detected under the better blocking interference resistance, so that the adjacent channel interference resistance and the blocking interference resistance can be balanced, and the optimal bilateral adjacent channel interference suppression effect is obtained.

The adjacent channel interference threshold represents the difference value between the maximum allowed adjacent channel interference signal intensity and the useful signal intensity, a preset adjacent channel interference threshold table can be preset, and the adjacent channel interference threshold in the preset adjacent channel interference threshold table corresponds to each group of local oscillation frequencies in the preset local oscillation frequency table one by one. In this embodiment, the preset local oscillator frequency table is set in an application scenario in which the low-if receiver is used as the local oscillator 114, and the technical solution of this embodiment is described in accordance with the preset adjacent channel interference threshold table determined and set by the preset local oscillator frequency table, but is not limited thereto.

Acquiring the frequency of the current local oscillator signal, namely assuming that the current local oscillator signal is in the nth group of local oscillator frequencies in the preset local oscillator frequency table, acquiring the nth adjacent channel interference threshold in the preset adjacent channel interference threshold table, and then judging whether the difference value between the signal intensity of the left adjacent channel interference signal and the signal intensity of the useful signal and the difference value between the signal intensity of the right adjacent channel interference signal and the signal intensity 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 executed. 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 determined 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 or not 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 or not.

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, go to step 73; if the difference between the signal intensity of the right adjacent channel interference signal and the signal intensity of the useful signal is less than the adjacent channel interference threshold or the difference between the signal intensity of the left adjacent channel interference signal and the signal intensity of the useful signal is not less than the adjacent channel interference threshold, judging whether the difference between the signal intensity of the right adjacent channel interference signal and the signal intensity of the useful signal is not less than the adjacent channel interference threshold or not and whether the difference between the signal intensity of the left adjacent channel interference signal and the signal intensity of the useful signal is not less than the adjacent channel interference threshold or not.

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, go to step 74; if the difference between the signal strength of the right adjacent channel interference signal and the signal strength of the desired signal and the difference between the signal strength of the left adjacent channel interference signal and the signal strength of the desired signal are both greater than or equal to the adjacent channel interference threshold, step 78 is executed.

Step 73: and if the difference between the signal intensity of the right adjacent channel interference signal and the signal intensity of the useful signal is greater than or equal to the adjacent channel interference threshold and the difference between the signal intensity of the left adjacent channel interference signal and the signal intensity of the useful signal is less than the adjacent channel interference threshold, adjusting the frequency of the local oscillation signal to be the low local oscillation 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 indicates that the influence of the right adjacent channel interference on the intermediate frequency signal is large under the current intermediate frequency, and exceeds the suppression limit of the current channel on the adjacent channel interference, and the influence of the left adjacent channel interference on the intermediate frequency signal is small, 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 the low local oscillator frequency corresponding to the current adjacent channel interference threshold.

Step 74: and if the difference value between the signal intensity of the right adjacent channel interference signal and the signal intensity of the useful signal is smaller than the adjacent channel interference threshold and the difference value between the signal intensity of the left adjacent channel interference signal and the signal intensity of the useful signal is larger than or equal to the adjacent channel interference threshold, adjusting the frequency of the local oscillation signal to be the high local oscillation 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 smaller 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, it indicates that the influence of the left adjacent channel interference on the intermediate frequency signal is large under the current intermediate frequency, and exceeds the suppression limit of the current channel on the interference signal, and the influence of the right adjacent channel interference on the intermediate frequency signal is small, at this time, the frequency of the intermediate frequency signal does not need to be adjusted, 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 be the high local oscillator frequency corresponding to the current adjacent channel interference threshold.

Step 75: and if the difference between the signal intensity of the right adjacent channel interference signal and the signal intensity of the useful signal and the difference between the signal intensity of the left adjacent channel interference signal and the signal intensity of the useful signal are both smaller than the adjacent channel interference threshold, judging whether the signal intensity of the right adjacent channel interference signal is larger than the signal intensity of the left adjacent channel interference signal.

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, which indicates that the influence of the left adjacent channel interference signal and the right adjacent channel interference signal on the intermediate frequency signal is smaller at the current intermediate frequency, the controller 117 may compare the received left adjacent channel interference signal with the received right adjacent channel interference signal, and select the adjacent channel interference signal with the smaller strength to obtain the better 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, go to step 76, otherwise go to step 77.

Step 76: and if the signal intensity of the right adjacent channel interference signal is greater than that of the left adjacent channel interference signal, adjusting the frequency of the local oscillation signal to be a low local oscillation frequency corresponding to the current adjacent channel interference threshold.

If the signal strength of the right adjacent channel interference signal is greater than the signal strength of the left adjacent channel interference signal, which indicates that the interference on the left adjacent channel is small, the controller 117 may control the local oscillator 114 to adjust the local oscillator frequency, so as to adjust the frequency of the local oscillator signal to a low local oscillator frequency corresponding to the current adjacent channel interference threshold.

Step 77: and if the signal intensity of the right adjacent channel interference signal is less than or equal to the signal intensity of the left adjacent channel interference signal, adjusting the frequency of the local oscillation signal to be the high local oscillation frequency corresponding to the current adjacent channel 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, which indicates that the interference on the right adjacent channel is small, the controller 117 may control the local oscillator 114 to adjust the local oscillator frequency, so as to adjust the frequency of the local oscillator signal to a high local oscillator frequency corresponding to the current adjacent channel interference threshold.

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

And 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, taking the next adjacent channel interference threshold as the current adjacent channel interference threshold, and returning to execute the 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 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 suppression degree in a 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 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 an adjacent channel interference threshold, it is indicated that under the current intermediate frequency, the influence of the right adjacent channel interference and the left adjacent channel interference on the intermediate frequency signal exceeds the maximum inhibition limit of the current channel on the interference signal, the adjacent channel interference resistance does not meet the condition, and the better adjacent channel interference resistance is not provided.

For example, the current local oscillation frequency in the nth group in the preset local oscillation frequency table and the adjacent channel interference threshold corresponding to the nth group local oscillation frequency are set to n +1, the frequency of the local oscillation signal in the (n + 1) th group is taken as the frequency of the current local oscillation signal, the adjacent channel interference threshold corresponding to the local oscillation frequency in the (n + 1) th group is taken as the current adjacent channel interference threshold, and the step 72 is returned until the difference between the signal intensity of the right adjacent channel interference signal and the signal intensity of the useful signal and/or the difference between the signal intensity of the left adjacent channel interference signal and the signal intensity of the useful signal are smaller 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, and the adjustment is stopped.

Step 79: and if the difference value 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, taking the next blocking interference threshold as the current blocking interference threshold.

Step 79 is similar to step 65 of the previous embodiment and will not be described again.

Referring to fig. 9, fig. 9 is a schematic structural diagram of an embodiment of a receiver provided in the present application, where the receiver 20 includes an antenna 21 and an adaptive anti-jamming device 10 connected to each other.

The antenna 21 is used for receiving radio frequency signals.

The adaptive immunity device 10 comprises a processing circuit 11 and a detection circuit 13 connected to each other.

The processing circuit 11 is configured to receive a radio frequency signal; selecting one local oscillation frequency from a preset local oscillation frequency table as the frequency of a local oscillation signal; and processing the local oscillator signal and the radio frequency signal to obtain an intermediate frequency signal.

Further, the processing circuit 11 is further configured to determine whether the signal strength of the interference signal meets a preset condition; if not, selecting another local oscillator frequency from the preset local oscillator frequency table as the frequency of the local oscillator signal, returning to execute processing on the local oscillator signal and the radio frequency signal to obtain the intermediate frequency signal until the signal intensity of the interference signal meets the preset condition or all local oscillator frequencies in the preset local oscillator frequency table are selected.

The following illustrates the implementation process and effect of the adaptive anti-interference method in this embodiment.

Example 1:

TABLE 1 Preset interference threshold Table

As shown in table 1, the third column is the interference rejection threshold corresponding to the current if frequency, and the fourth column is the adjacent channel interference threshold corresponding to the current if frequency. Along with the reduction of the intermediate frequency, the blocking interference threshold is reduced, the blocking interference threshold is increased, namely, the anti-blocking interference capability is reduced, and the adjacent channel interference resistance is improved. Because the higher the intermediate frequency is, the stronger the anti-blocking interference capability is, but the poorer the anti-adjacent channel interference capability is, the frequency of the intermediate frequency signal is changed by adjusting the frequency of the local oscillator signal, so that the anti-adjacent channel interference capability and the anti-blocking interference capability both meet the requirement under a certain intermediate frequency, and the anti-interference capability can be realized under the complex environment in which the double-adjacent channel interference and the blocking interference exist at the same time; it is understood that the data in table 1 is only an example, and the specific values can be adjusted according to the actual application.

Example 2:

TABLE 2 interphone test results with low-IF receiver

L, M, H is three different channels, the channel interval is 12.5KHz, L is a low frequency channel, M is an intermediate frequency channel, and H is a high frequency channel; as shown in table 2, for three channels L, M, H of 2 models of interphones, the method of the present embodiment and the existing method are used to perform the reference sensitivity, the anti-blocking interference capability and the anti-adjacent channel interference capability test, respectively.

As can be seen from table 2, the reference sensitivity and the anti-blocking interference capability of the intercom are not substantially affected by the presence or absence of the adaptive anti-interference method of the present embodiment, but the anti-interference capability of the adjacent channel is significantly affected by the anti-interference method of the present embodiment, the anti-interference capability of the adjacent channel is less than 45dB when the existing method is used, the anti-interference capability of the adjacent channel reaches 70dB after the method of the present embodiment is used, and the anti-interference capability of the adjacent channel is significantly improved.

Example 3

Referring to fig. 8 and table 3, fig. 8 is a schematic diagram of an interference interruption test in an embodiment of the adaptive interference avoidance method provided in the present application, in which an interference source 81 is utilized to generate an interference signal to test a receiver 20, and assuming that a channel frequency (F1) is 436.625MHz, a blocking interference signal frequency is F1+10MHz, a right adjacent channel interference signal frequency is F1+12.5kHz, and a left adjacent channel interference signal frequency is F1-12.5kHz, the test results shown in table 3 can be obtained.

TABLE 3 anti-interference interruption test results

The Digital channel may be a Digital Mobile Radio channel (DMR).

The radiation test is a judgment standard which is the distance between a specific position where a useful signal disappears in a channel (namely the signal intensity of the useful signal is 0) and the receiver 20 due to interference in the transmission process of the signal; as can be seen from table 3, for the device not using the interference immunity method of this embodiment, the distance from the position where the useful signal disappears to the receiver 20 is greater than 10m, while after using the interference immunity method of this embodiment, the distance from the position where the useful signal disappears to the receiver 20 is about 1m, and the distance is significantly shortened, so that the interference immunity capability is significantly improved by using the interference immunity adaptive method of this embodiment.

The conduction test takes the signal intensity of a useful signal at the same position in the transmission process of the signal as a judgment standard; as can be seen from table 3, for a device not using the interference rejection method of the present embodiment, the signal intensity of the useful signal at a certain position is about 35dB, while after using the interference rejection method of the present embodiment, the signal intensity of the useful signal at the same position is about 65dB, so that the influence of the interference source 81 on signal transmission can be reduced by using the interference rejection method of the present embodiment.

According to test data, the anti-interference self-adaption method of the embodiment can shorten the distance from the vanishing position of the signal to the receiver 20 and reduce the influence of the interference source 81 on signal transmission under the complex environments of single/double adjacent channel interference or single/double adjacent channel blocking interference and the like, so that the signal strength of the same position is increased compared with that of the existing method, and the anti-interference capability is improved.

The scheme of this embodiment judges whether need to adjust the frequency of local oscillator signal according to the signal strength of blocking interference signal, the signal strength of adjacent channel interference signal and the signal strength of useful signal, adjusts the frequency of local oscillator signal, makes the frequency of intermediate frequency signal change, can counter adjacent channel interference and anti-blocking interference and carry out the equilibrium, makes under certain intermediate frequency, the ability of anti-adjacent channel interference and the ability of anti-blocking interference all meet the requirements, help improving the interference killing feature.

The above description is only for the purpose of illustrating embodiments of the present application and is not intended to limit the scope of the present application, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the specification and the drawings of the present application or are directly or indirectly applied to other related technical fields, are also included in the scope of the present application.

Claims

1. An adaptive interference rejection method, the method comprising:

receiving a radio frequency signal;

selecting one local oscillation frequency from a preset local oscillation frequency table as the frequency of a local oscillation 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 intensity of an interference signal, wherein the interference signal comprises a blocking interference signal and an adjacent channel interference signal;

judging whether the signal intensity of the interference signal meets a preset condition or not;

if not, selecting another local oscillator frequency from the preset local oscillator frequency table as the frequency of the local oscillator signal, and returning to execute the step of processing the local oscillator signal and the radio frequency signal to obtain an intermediate frequency signal until the signal intensity of the interference signal meets the preset condition or all local oscillator frequencies in the preset local oscillator frequency table are selected completely.

2. The adaptive interference rejection method according to claim 1, wherein said step of selecting one local oscillation frequency from a preset local oscillation frequency table as the frequency of the local oscillation signal comprises:

and selecting the maximum local oscillation frequency in the preset local oscillation frequency table as the frequency of the local oscillation signal.

3. The adaptive anti-interference 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:

and mixing the local oscillator signal with the radio frequency signal to generate the intermediate frequency signal.

4. The adaptive interference rejection method according to claim 1, wherein said step of performing interference detection on said radio frequency signal and said intermediate frequency signal to obtain a signal strength of an 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 intensity of the blocking interference signal;

and carrying out adjacent channel interference detection on the intermediate frequency signal to obtain the signal intensity of the adjacent channel interference signal.

5. The adaptive interference rejection method according to claim 4, wherein said step of performing adjacent channel interference detection on said intermediate frequency signal to obtain a signal strength of said adjacent channel interference signal comprises:

performing analog-to-digital conversion on the intermediate frequency signal to obtain a digital signal;

and carrying out adjacent channel interference detection on the channel where the digital signal is located to obtain the signal intensity of the adjacent channel interference signal.

6. The adaptive interference rejection method according to claim 5, further comprising:

and processing the digital signal to generate a useful signal, and detecting the signal intensity to obtain the signal intensity of the useful signal.

7. The adaptive interference rejection 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 step of determining whether the signal strength of the interference signal satisfies a predetermined condition includes:

judging whether the difference value between the signal intensity of the right adjacent channel interference signal and the signal intensity of the useful signal is greater than a right adjacent channel interference threshold or not;

if so, judging whether to adjust the frequency of the local oscillator signal by using the signal intensity of the left adjacent channel interference signal, the signal intensity of the right adjacent channel interference signal, the signal intensity of the useful signal and the signal intensity of the blocking interference signal;

and if not, the frequency of the local oscillator signal is not adjusted.

8. The adaptive interference rejection method according to claim 7, wherein said step of determining whether to adjust the frequency of the local oscillator signal by using 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 desired signal, and the signal strength of the blocking interference signal comprises:

judging whether the difference value between the signal intensity of the left adjacent channel interference signal and the signal intensity of the useful signal is greater than a left adjacent channel interference threshold or not;

if the difference between the signal intensity of the left adjacent channel interference signal and the signal intensity of the useful signal is greater than the left adjacent channel interference threshold, calculating the difference between the signal intensity of the blocking interference signal and the signal intensity of the useful signal, and judging whether to adjust the frequency of the local oscillator signal by using the difference between the signal intensity of the blocking interference signal and the signal intensity of the useful signal, the signal intensity of the left adjacent channel interference signal and the signal intensity of the right adjacent channel interference signal;

and if the difference value between the signal intensity of the left adjacent channel interference signal and the signal intensity 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.

9. The adaptive interference rejection method according to claim 8, wherein the preset local oscillator frequency table includes a plurality of groups of local oscillator frequencies, each group of local oscillator frequencies includes a high local oscillator frequency and a low local oscillator frequency, each group of local oscillator frequencies corresponds to a blocking interference threshold in a preset blocking interference threshold table, and the step of determining whether to adjust the frequency of the local oscillator signal by using a 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 includes:

judging whether the difference value between the signal intensity of the blocking interference signal and the signal intensity of the useful signal is larger than the next blocking interference threshold of the current blocking interference threshold or not;

if the difference between the signal strength of the jamming interference signal and the signal strength of the useful signal is greater than the next jamming interference threshold, judging whether the signal strength of the right adjacent channel jamming signal is greater than the signal strength of the left adjacent channel jamming signal;

if the signal intensity of the right adjacent channel interference signal is greater than the signal intensity 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 intensity of the right adjacent channel interference signal is less than or equal to the signal intensity of the left adjacent channel interference signal, adjusting the frequency of the local oscillation signal to the high local oscillation 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, taking the next blocking interference threshold as the current blocking interference threshold, and returning 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 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.

10. An adaptive interference rejection device, comprising:

processing circuitry to receive a radio frequency signal; selecting one local oscillation frequency from a preset local oscillation frequency table as the frequency of a local oscillation signal; processing the local oscillator signal and the radio frequency signal to obtain an intermediate frequency signal;

the detection circuit is connected with the processing circuit and is used for carrying out interference detection on the radio frequency signal and the intermediate frequency signal to obtain the signal intensity of an interference signal, wherein the interference signal comprises a blocking interference signal and an adjacent channel interference signal;

the processing circuit is further configured to determine whether the signal strength of the interference signal meets a preset condition; if not, selecting another local oscillator frequency from the preset local oscillator frequency table as the frequency of the local oscillator signal, returning to execute processing on the local oscillator signal and the radio frequency signal to obtain an intermediate frequency signal until the signal intensity of the interference signal meets the preset condition or all local oscillator frequencies in the preset local oscillator frequency table are selected completely.

11. A receiver, comprising:

an interconnected antenna and an adaptive interference rejection device according to claim 10.