Interphone control signal anti-interference method and system

Abstract

The invention belongs to the technical field of wireless communication networks, and relates to an interphone control signal anti-interference method and system, and the method comprises the following steps: obtaining an original signal of an interphone channel, and monitoring a dynamic change value of signal energy in real time; triggering a jump starting event when an energy jump characteristic conforming to instantaneous sudden increase in the original signal is identified; after the jump starting event occurs, tracking a subsequent energy stable state of the signal, and generating a steady state holding event when it is detected that the stable strength of the signal in a preset fluctuation allowable boundary reaches a preset continuous holding reference duration; recording a spectrum contradiction event; capturing an energy attenuation form in a signal ending stage, and generating an ordered ending event; verifying the event chain logic sequence, and judging the event chain logic sequence as an effective control operation sequence; and executing a channel switching or calling control instruction corresponding to the interphone. According to the invention, the fundamental defects of high response delay and poor scene adaptability in the traditional mode are overcome.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wireless communication networks, and relates to a walkie-talkie control signal anti-interference method and system. BACKGROUND

[0002] The walkie-talkie system faces the problem of control signal false triggering in a complex electromagnetic environment. When the device is in an industrial site or a densely populated urban radio area, environmental noise and burst interference can cause the device to incorrectly identify non-operation signals. The traditional method based on a simple energy threshold cannot distinguish between real user operations and electromagnetic interference, frequently causing channel mis-switching or talk circuit mis-starting. Such false triggering not only causes communication interruption, but in security or emergency scenarios can also cause critical instructions to be lost.

[0003] Traditional solutions mainly rely on signal content decoding or fixed time length energy integration. The mainstream technology verifies the operation validity by modulating and demodulating the control signal and protocol analysis, and some improved schemes use the method of extending the energy integration window to smooth the interference. After receiving a suspected control signal, a continuous energy average value calculation of several hundred milliseconds is started, and only when the preset threshold is exceeded is it determined as a valid operation. This method attempts to increase the reliability by adding a verification link.

[0004] Based on the above problems, the fixed integration window scheme will still produce false judgments when encountering continuous interference and cannot identify the spectrum camouflage attack with deceptive characteristics, that is, the traditional method has the fundamental defects of high response delay and poor scene adaptability. SUMMARY

[0005] In a first aspect, the application provides a walkie-talkie control signal anti-interference method, which adopts the following technical scheme:

[0006] A walkie-talkie control signal anti-interference method, comprising the following steps:

[0007] S1, obtaining the original signal of the walkie-talkie channel, and monitoring the dynamic change value of the signal energy in real time;

[0008] S2, identifying the energy jump characteristic conforming to the instantaneous sudden increase in the original signal, and triggering a jump start event;

[0009] S3, after the jump start event occurs, tracking the energy stable state of the signal, and when detecting that the signal maintains a stable intensity within a preset fluctuation allowable boundary for a preset continuous maintenance reference time length, generating a stable state maintenance event;

[0010] S4, during the existence of the stable state maintenance event, analyzing the energy evolution trajectory of a preset key frequency point, and when detecting that the preset key frequency point appears non-coherent fluctuation or a sudden drop amplitude exceeding a preset proportional tolerance limit, recording a spectrum contradiction event;

[0011] S5, capturing the energy attenuation pattern of the signal end stage to generate an orderly termination event;

[0012] S6, verifying the logical sequence of the event chain: the jump start event precedes the steady state maintenance event, the steady state maintenance event precedes the orderly termination event, and there is no spectrum contradiction event, and determining that it is a valid control operation sequence;

[0013] S7, only after the valid control operation sequence verification passes, executing the channel switching or talk control instruction corresponding to the intercom.

[0014] Further schemes of the present application, acquiring the original signal of the intercom channel, comprising the following steps:

[0015] Connecting the intercom preset communication channel through the hardware receiving circuit, and collecting the energy intensity of the carrier signal;

[0016] Quantitative sampling the energy intensity according to the preset sampling time interval to obtain a time series numerical stream reflecting the energy size, and the time series numerical stream refers to the data stream formed by arranging the energy intensity digital values obtained by quantitative sampling in chronological order;

[0017] Calculating the absolute difference value of the energy intensity of adjacent sampling points to output the dynamic change value of the signal energy.

[0018] Further schemes of the present application, triggering the jump start event, comprising the following steps:

[0019] The continuously output dynamic change value of the signal energy is used as the basic data source, and a preset time window larger than the preset sampling time interval is set;

[0020] Accumulating the dynamic change values of all signal energies in the preset time window to generate a window dynamic change cumulative value;

[0021] When the window dynamic change cumulative value exceeds the preset steep rise amplitude reference value, and the maximum single dynamic change value in the window reaches the preset minimum jump requirement, the jump start event is triggered.

[0022] Further schemes of the present application, generating the steady state maintenance event, comprising the following steps:

[0023] After the jump start event is triggered, the processing unit immediately starts a new round of monitoring window of the dynamic change value of the signal energy, and the new round of monitoring window of the dynamic change value of the signal energy continuously slides to track each subsequent dynamic change value of the signal energy;

[0024] When the continuous monitoring duration reaches the preset continuous maintenance reference duration, it is verified that all dynamic change values are within the preset fluctuation allowable boundary;

[0025] If all the dynamic change values are verified to be within the preset fluctuation allowable boundary, a steady state maintaining event is generated; if any signal energy dynamic change value is detected to be beyond the fluctuation allowable boundary, the accumulated time length is immediately emptied and the checking process is reset.

[0026] In further aspects of the present application, a spectrum contradiction event is recorded, comprising the following steps:

[0027] During the period when the flag signal of the steady state maintaining event is active, the processing unit enables the fast Fourier transform coprocess module to perform frequency division processing on the output raw signal to extract the energy value sequence of the preset key frequency point;

[0028] Each time a new key frequency point energy value reading is obtained, the absolute difference between the current reading and the previous reading is calculated;

[0029] If the absolute difference exceeds the proportional tolerance limit set based on the current stable intensity reference value or if the amplitude of the continuous multiple jumps is greater than the preset continuity threshold, a spectrum contradiction event is immediately generated if any abnormal fluctuation is detected.

[0030] In further aspects of the present application, an orderly termination event is generated, comprising the following steps:

[0031] When the flag signal of the steady state maintaining event is turned into an inactive state, i.e. the moment when the output logic trigger signal is switched from high level to low level, the final energy intensity value at the end time of the steady state maintaining event is taken as the decay starting reference line, which is the reference metric value of the decay start;

[0032] Each time an updated reading is obtained, the difference between the new energy intensity value and the previous recorded value in the current decay period is calculated;

[0033] If the difference is continuously negative and its absolute value is within the allowable decrease step interval formed by the preset lower limit of unit decrease amplitude and the upper limit of unit decrease amplitude, and if the total decay time length is between the preset shortest complete decay time length and the longest reasonable decay time length, an orderly termination event is immediately generated when the energy intensity is detected to be stable to the termination judgment value close to the background noise level.

[0034] In further aspects of the present application, the event chain logic sequence is verified, comprising the following steps:

[0035] An event state register containing the time stamps of each event is established;

[0036] The event state register refers to a specially opened storage space for recording the logic state of the event trigger signal generated by each independent step and its accurate microsecond-level timing mark in real time;

[0037] The value of the time stamp refers to the absolute time count value recorded by using the high-precision timer of the system at the moment when the event flag signal is effectively changed.

[0038] Forcing interrupt verification when detecting spectrum contradiction event marker;

[0039] When there is no spectrum contradiction event, verifying that the jump start event timestamp is less than the steady state holding event timestamp, which is less than the ordered termination event timestamp, and the duration from steady state holding to ordered termination is within the preset reasonable operation duration interval.

[0040] Further schemes of the present application, determining an effective control operation sequence, include the following steps:

[0041] The jump start occurrence point value is less than the steady state holding start occurrence point value; and the steady state holding start occurrence point value is less than the ordered termination occurrence point value;

[0042] The time difference between the steady state holding occurrence point and the ordered termination occurrence point needs to be within the reasonable interval between the preset minimum behavior duration and the maximum operation duration;

[0043] Only when all conditions are met synchronously, the signal constituting the effective control operation sequence is determined.

[0044] Further schemes of the present application, executing the intercom corresponding channel switching or talk control instruction, include the following steps:

[0045] When the effective control operation sequence verification is passed, extracting the preset operation type distinguishing code associated with the jump start event;

[0046] Generating the instruction trigger signal of channel switching or talk control according to the operation type distinguishing code;

[0047] Sending the instruction trigger signal to the execution unit.

[0048] In a second aspect, the present application provides a kind of intercom control signal anti-interference system, using the following technical scheme:

[0049] An intercom control signal anti-interference system includes the following modules:

[0050] Signal dynamic monitoring module, for acquiring the original signal of intercom channel, real-time monitoring the dynamic change value of signal energy;

[0051] Jump event trigger module, for identifying the energy jump feature of instantaneous sudden increase in the original signal, triggering the jump start event;

[0052] Steady state event generation module, after the jump start event occurs, track the subsequent energy stability of signal, when detecting that the smooth intensity maintained within the preset fluctuation allowed boundary reaches the preset duration reference length, generate steady state holding event;

[0053] a spectrum contradiction detection module, during the duration of the steady-state maintenance event, analyzing the energy evolution trajectory of a preset key frequency point, and when detecting that the preset key frequency point has a non-coherent fluctuation or a sudden drop in amplitude that exceeds a preset proportional tolerance limit, recording a spectrum contradiction event;

[0054] a decay pattern capture module for capturing the energy decay pattern of the signal end phase to generate an orderly termination event;

[0055] an event chain verification module for verifying the logical sequence of the event chain: the jump start event precedes the steady-state maintenance event, the steady-state maintenance event precedes the orderly termination event, and there is no spectrum contradiction event, and determining that it is a valid control operation sequence;

[0056] an instruction execution control module for executing the intercom corresponding channel switching or talk control instruction only after the valid control operation sequence verification is passed.

[0057] In summary, the present application includes the following beneficial technical effects:

[0058] 1. The one-vote veto system of the spectrum contradiction event and the timing logic double verification strategy ensure that any abnormal signal fluctuation will interrupt the instruction execution process. The system strictly follows the irreversible event sequence of jump start before steady-state maintenance and steady-state maintenance before orderly termination, fundamentally eliminating the risk of misoperation caused by signal interception or malicious interference.

[0059] 2. Based on the light-weight real-time calculation of the dynamic change value of the signal energy, the traditional speech encoding and decoding and semantic analysis process is replaced, and the processing delay is shortened to milliseconds. The special FFT coprocessor only needs to activate the key frequency point analysis module during the steady-state maintenance period, so that the system can run efficiently on a low-power embedded platform and provide hardware-level security protection for critical communication scenarios.

[0060] 3. Time domain energy trajectory analysis, frequency domain feature monitoring and decay pattern capture are deeply integrated to form a cross-dimensional cross-verification system. The parallel execution of spectrum contradiction detection and decay step verification produces a synergistic anti-interference effect, which improves the recognition accuracy of the system for disguised attack signals and breaks through the technical bottleneck of traditional solutions. BRIEF DESCRIPTION OF DRAWINGS

[0061] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. The drawings are used to provide a further understanding of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0062] Fig. 1 The flowchart of the embodiments of the present application is disclosed.

[0063] Fig. 2 The structural schematic diagram in the embodiment of the application is disclosed. DETAILED DESCRIPTION

[0064] In order to make the purpose, technical scheme and advantages of the embodiments of the application clearer, the technical scheme in the embodiments of the application will be clearly and completely explained in combination with the drawings of the embodiments of the application. Obviously, the described embodiments are some but not all of the embodiments of the application. All other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the application.

[0065] The drawings will be described below in combination with the Figs. 1-2 The preferred detailed description of the application is made.

[0066] The drawings will be described below in combination with the Fig. 1 The application provides an intercom control signal anti-interference method, comprising the following steps:

[0067] S1, acquiring an original signal of an intercom channel, and monitoring a dynamic change value of signal energy in real time;

[0068] S2, identifying an energy jump-up feature conforming to instantaneous surge in the original signal, and triggering a jump start event;

[0069] S3, after the jump start event occurs, tracking a subsequent energy stable state of the signal, and when detecting that a smooth intensity of the signal maintained within a preset fluctuation allowable boundary reaches a preset continuous maintenance reference time length, generating a stable state maintenance event;

[0070] S4, during the stable state maintenance event, analyzing an energy evolution track of a preset key frequency point, and when detecting that a non-coherent fluctuation or a sudden drop amplitude of the preset key frequency point exceeds a preset proportional tolerance limit, recording a spectrum contradiction event;

[0071] S5, capturing an energy decay pattern of an end stage of the signal, and generating an orderly termination event;

[0072] S6, verifying an event chain logical sequence: the jump start event precedes the stable state maintenance event, the stable state maintenance event precedes the orderly termination event, and there is no spectrum contradiction event, and determining that it is a valid control operation sequence;

[0073] S7, only after the valid control operation sequence is verified, executing an intercom corresponding channel switching or talk control instruction.

[0074] In one of the embodiments of the application, step S1 comprises the following steps:

[0075] The original signal of the intercom channel is acquired, and the original signal refers to the carrier signal on the predetermined communication channel without any decoding, demodulation or content analysis, which purely reflects the instantaneous energy intensity of electromagnetic waves; the dynamic change value of the signal energy is monitored in real time.

[0076] Specifically, the hardware receiving circuit is directly connected to the predetermined communication channel of the intercom, and the hardware receiving circuit refers to a specially designed radio frequency front-end circuit, which is used to capture the carrier signal without demodulation processing from the predetermined radio frequency range and convert it into an analog or digital electrical signal intensity value for subsequent processing. The predetermined communication channel refers to a specific radio frequency range designated by the intercom system design for signal transmission, usually 136-174MHz (VHF ultra-high frequency band, commonly used for open area communication) or 400-470MHz (UHF ultra-high frequency band, commonly used for building area communication). The hardware receiving circuit continuously collects the energy intensity of the carrier signal, and the energy intensity represents the numerical value of the power of the captured electromagnetic wave in a unit of time.

[0077] The energy intensity is quantitatively sampled according to the preset sampling time interval to obtain a time series numerical value stream reflecting the energy size. The time series numerical value stream refers to a data stream formed by arranging the energy intensity digital values obtained by quantitative sampling in chronological order. The difference amplitude between the latest obtained sampling value and the previous sampling value presents the trend of energy change between adjacent two sampling points in an absolute value manner, that is, the dynamic change value of the signal energy.

[0078] Satisfies the following formula:

[0079] ΔE(t) = |P(t) - P(t-Δt)|

[0080] Where ΔE(t) is the dynamic change value of the signal energy; Δt is the sampling time interval, the setting range of the sampling time interval is 0.1ms-50ms, and the typical value is 5ms-10ms; P(t) is the sampling value of the signal power at time t; P(t-Δt) is the sampling value of the signal power adjacent to P(t). Quantitative sampling refers to the process of converting continuous analog energy intensity values into discrete digital values according to the preset sampling time interval (which is smaller than the time scale of possible drastic changes in the signal). This process completely bypasses the identification of whether the original signal carries speech or control instructions and directly operates based on the energy information of the physical layer carrier.

[0081] For example, assume a speakerphone system, the hardware receiving circuit is connected to a channel with a working frequency of 400 MHz, which is used for building area communication. After the hardware receiving circuit is turned on, the analog-to-digital converter inside the hardware receiving circuit always quantitatively samples the energy intensity of the electromagnetic wave at this frequency point at a speed of more than several thousand times per second, and each sampling point corresponds to an instantaneous energy value reading.

[0082] The processing unit does not attempt to understand whether these readings represent human speech, but compares each newly read energy value (denoted as current intensity) with its immediately preceding read energy value (denoted as previous intensity), calculates and stores the absolute value of the difference between the current intensity and the previous intensity. This absolute value is the dynamic change value of the signal energy at this moment, and the dynamic change value of the signal energy is continuously output as a new sequence. If an external signal suddenly enters the channel, its energy intensity will quickly rise or fluctuate sharply, resulting in a large peak value in the dynamic change value sequence calculated in a short time; the change value of the signal or the stable signal state presents small amplitude fluctuations. The whole process is independent of signal content analysis and only focuses on the fluctuation of energy itself.

[0083] In one embodiment of the present application, step S2 includes the following steps:

[0084] Identify whether the original signal meets the characteristics of instantaneous energy jump, which refers to the sudden increase of the energy intensity of the carrier signal within a preset time window, and the change rate of the energy intensity of the carrier signal is significantly higher than the environmental noise fluctuation. When the energy intensity exceeds the preset steep rise reference value within the preset time window, a jump start event is triggered.

[0085] Specifically, the continuously output dynamic change value of the signal energy is used as the basic data source, a preset time window with a time span greater than the sampling time interval of step S1 is set to intercept data segments, and the preset time window refers to the fixed time period set by the processing unit, which is used to frame the range of dynamic change value of the signal energy to be analyzed. The length of the preset time window is sufficient to cover the whole process of signal energy from static to dramatic change. The preset time window is dynamically adjusted according to the main fluctuation period of the environmental noise and the sampling time interval, for example, the lower limit of the preset time window is more than 25 times the sampling time interval, ensuring that the window contains at least 25 sampling points; the upper limit of the preset time window is not more than 6 times the main fluctuation period of the environmental noise, avoiding excessive smoothing of the burst signal.

[0086] The dynamic change values falling within the preset time window are accumulated and summed in real time to obtain a window dynamic change cumulative value within the preset time window. The setting of the preset time window ensures that it is greater than the natural fluctuation period of the environmental noise. The window dynamic change cumulative value represents the overall intensity of the signal energy fluctuation in the time period. The window dynamic change cumulative value is compared with a preset steep rise amplitude reference value. If the window dynamic change cumulative value exceeds the preset steep rise amplitude reference value and simultaneously meets the condition that the maximum single dynamic change value within the preset time window reaches the minimum jump requirement, it is determined that an energy jump in accordance with the instantaneous sudden increase feature occurs. A jump start event is generated immediately. The jump start event is a logical trigger signal output when the energy jump feature is confirmed. The macro statistical feature of energy change is cooperatively judged with the instantaneous peak value, and the signal frequency content analysis is not involved. The following formula is satisfied:

[0087] max(ΔE(t), ΔE(t+Δt), …, ΔE(t+nΔt)) ≥ ΔE min

[0088] where ΔE(t) represents the dynamic change value of the signal energy; n represents the number of sampling points within the preset time window, which satisfies n=T w / Δt, where T w represents the length of the preset time window, and Δt represents the sampling time interval; ΔE min represents the minimum jump requirement, which is taken from the minimum effective mutation of the key operation and is a baseline value preset according to the minimum measurable signal strength change quantity necessarily produced when the actual operation is performed on the physical key of the intercom. The setting range is 25dB-45dB, and the typical value is 30dB.

[0089] where the preset steep rise amplitude reference value is determined according to the historical signal energy dynamic change value data of long-term monitoring of the intercom use environment and a safety margin is reserved. The value threshold is set by multiplying the upper limit of the total energy natural fluctuation of the noise background by a safety amplification coefficient. The safety amplification coefficient is an empirical multiplier for amplifying the upper limit of the total fluctuation of the noise background. It is usually between 1.2 and 2.0, and the typical value is 1.5. The specific value depends on the application scenario.

[0090] For example, step S1 outputs the dynamic change value of the signal energy with a sampling time interval of Δt=0.1ms. The processing unit opens a 10ms long preset time window in real time. All 100 (10ms / 0.1ms) signal energy dynamic change values within the preset time window are added and summed. At the same time, the maximum single dynamic change value within the window is monitored.

[0091] Suppose the window dynamic change cumulative value of an operation reaches 200 dB (exceeds the preset 150 dB steep rise amplitude reference value), a single dynamic change value of 50 dB (satisfies the greater than minimum jump requirement of 30 dB) is found in the preset time window to generate a jump start event. If only the total exceeds the standard but the maximum change value is less than 30 dB, or the total is less than 150 dB but there is a single point of severe fluctuation, neither triggers the jump start event. Through multiple measurements of environmental noise by the electromagnetic wave intensity meter, it is known that the peak value of the total amount of natural fluctuation within 10 ms is usually 100 dB, and the steep rise amplitude reference value is set to 150 dB (100 dB X 1.5) to exclude environmental interference; the pressing experiment proves that physical buttons will at least generate a single point mutation of more than 30 dB, and accordingly the minimum jump requirement is set.

[0092] In one embodiment of the present application, step S3 comprises the following steps:

[0093] After the jump start event of step S2 occurs, the subsequent energy stability state of the signal is tracked, and when the signal maintains a stable intensity within the fluctuation allowed boundary for a preset continuous maintenance reference time length, a steady state maintenance event flag signal is generated.

[0094] Specifically, after the jump start event flag signal of step S2 is generated, the processing unit immediately starts a new round of monitoring window for the dynamic change value of the signal energy. The jump start event flag signal is a logical trigger signal sent by step S2 after identifying the energy jump feature, and is the only starting condition for the execution of the present step. The new round of monitoring window for the dynamic change value of the signal energy continuously tracks the dynamic change value of each subsequent signal energy, and checks each value one by one to see whether it falls within the fluctuation allowed boundary defined between the fluctuation upper limit and the fluctuation lower limit. The continuously sliding monitoring window refers to the new data coverage section created immediately after the jump start event, and the length covers the entire process from the event trigger time to the satisfaction or termination of the check condition.

[0095] The steady state maintenance event flag signal satisfies the condition: only when t s The ΔE(t) of each time t within the time length τ does not exceed the fluctuation allowed boundary [ΔE L , ΔE H ], and τ ≥ τ min , the processing unit outputs the steady state maintenance event flag signal.

[0096] Wherein, t s represents the trigger time of the jump start event, representing the starting time point of the significant jump change of the signal energy (such as user operation start or external event trigger). ΔE(t) represents the dynamic change value of the signal energy. τ represents the cumulative time length of the new round of monitoring window, representing that ΔE(t) continuously remains within the fluctuation allowed boundary [ΔE L,ΔE H ] within a time length.

[0097] [ΔE L ,ΔE H ] represents the fluctuation allowed boundary, ΔE L represents the fluctuation lower limit, set as 0.1σ (e.g. 0.3dB); ΔE H is the fluctuation upper limit, set as 3σ (e.g. 9dB); based on the statistical distribution (e.g. standard deviation σ) of the dynamic change values ΔE(t) of the signal energy under the background noise, the fluctuation allowed boundary range is set as [0.1σ, 3σ] considering the maximum amplitude of the system noise level and common interference. If any of the dynamic change values of the signal energy is detected to exceed the fluctuation allowed boundary, the accumulated time length is immediately emptied and the checking process is reset.

[0098] τ min represents the continuously maintained reference time length, representing the preset minimum time length that the signal energy change continuously remains within the range [ΔE L , ΔE H ], used to define the reference of steady state maintenance, which is lower than the minimum operation time length that the human user intentionally maintains the signal stability (e.g. 800ms for continuous pressing), but significantly longer than the duration of common burst interference (e.g. 200ms), ensuring effective filtering of short-term interference to avoid false triggering.

[0099] For example, the processing unit receives the jump start event (e.g. the flag bit jumps from 0 to 1) issued in step S2 and immediately starts the tracking function. The fluctuation allowed boundary is set as [0.3dB, 9dB], and the continuously maintained reference time length is 300ms. The first detected subsequent dynamic change value is 3dB, which falls within the pre-defined fluctuation allowed boundary [0.3dB, 9dB], and the timer accumulates a time length of 1ms; the next value is 5dB (still falling within the pre-defined fluctuation allowed boundary), and the accumulated time length increases to 2ms; such continuous detection continues until the 200th detected value is between 2dB and 7dB, and the accumulated time length of the new monitoring window reaches 200ms. If the 200ms requirement is not met, the monitoring continues, and the 250th detected value is detected as 10dB (exceeding the fluctuation upper limit 9dB). The processing unit immediately empties the accumulated time length and resets the checking process, determining that the current checking fails and no event is generated.

[0100] In another operation, if the 300 consecutive dynamic values (corresponding to the reference duration of 300 ms) are maintained between, for example, 1 dB-6 dB, without once exceeding the boundary, when the 300 ms condition is met, a flag signal of the steady-state holding event is generated. The fluctuation allowed boundary is usually σ=3 dB according to the long-term measured background noise fluctuation amplitude; the reference duration of 300 ms is set according to the experimental statistics that more than 90% of the short burst interference pulse width is less than 200 ms, and the operation characteristic that the user's fastest continuous pressing of the key needs 800 ms.

[0101] In one embodiment of the present application, step S4 comprises the following steps:

[0102] During the active state of the flag signal of the steady-state holding event output by step S3, the energy evolution trajectory of the preset key frequency point is analyzed, and when the non-coherent fluctuation or sudden drop amplitude of the preset key frequency point is detected to exceed the proportional tolerance limit, a spectrum contradiction event is recorded.

[0103] Specifically, during the active state of the flag signal of the steady-state holding event output by step S3, i.e., the effective period of the present step, the processing unit enables the Fast Fourier Transform (FFT) coprocessing module to perform frequency division processing on the original signal output by step S1. The Fast Fourier Transform (FFT) coprocessing module locks the center position of the preset key frequency point and continuously extracts the signal energy value in the narrowband range near the preset key frequency point. The preset key frequency point refers to the specific center frequency F c and its binding narrowband range, which is disclosed by the equipment technical specification document, form the sequence of key frequency point energy values. c and its binding narrowband range, which is disclosed by the equipment technical specification document, form the sequence of key frequency point energy values.

[0104] The Fast Fourier Transform (FFT) coprocessing module refers to a physically separated special hardware unit in the processing unit. The core function is to perform alignment and comparative analysis of the sequence of key frequency point energy values and the steady-state dynamic change value (time series numerical flow) of the signal energy in the same time period recorded by the new round of monitoring window of step S3 through an optimized parallel computing architecture.

[0105] When a new key frequency energy value reading is obtained, the absolute difference between the new reading and the previous reading is calculated, and it is determined whether the absolute difference exceeds a proportional tolerance limit set based on the current stable intensity reference value. The current stable intensity reference value refers to the average result of measuring the key frequency energy value at the initial stage of the steady state maintenance event, representing the energy reference point of the effective period. The proportional tolerance limit refers to the single change amplitude of the key frequency energy value within the normal fluctuation range allowed in the stable signal state. The numerical value of the proportional tolerance limit is determined by multiplying the stable intensity reference value by a proportional tolerance coefficient. The proportional tolerance coefficient is set by referring to the maximum historical statistical value of the signal total energy change intensity fluctuation ratio. The proportional tolerance coefficient is usually set in the range of 0.2 to 0.8, and the typical value is 0.2.

[0106] At the same time, the sequence of key frequency energy values is checked to see if there is a situation where the amplitude of continuous multiple jumps is greater than the continuity threshold, which is a non-continuity fluctuation. The continuity threshold refers to the maximum allowed value of the absolute difference between the measured key frequency energy values of adjacent two times, which is the statistical upper limit value of the continuous change rate in normal operation, and the value range is 15% to 30% of the current stable intensity reference value. If any abnormal fluctuation is detected, a spectrum contradiction event is immediately generated.

[0107] For example, assuming that the preset key frequency is 410 MHz and its binding narrowband range is 2 kHz, after the FFT coprocessor module receives the active steady state maintenance event flag signal, it starts to calculate and output the sequence of key frequency energy values at 1 ms intervals. The average of the key frequency energy values in the first 20 ms after the steady state maintenance event flag signal is activated is taken, and the current stable intensity reference value is 100 dB. The proportional tolerance coefficient is set to 0.2, i.e. the numerical value of the proportional tolerance limit is 20 dB.

[0108] The key frequency energy value read at the 25th ms is 105 dB, and the absolute difference from the current stable intensity reference value of 100 dB is 5 dB, which is less than the proportional tolerance limit of 20 dB, indicating that the single change amplitude of the key frequency energy value is within the normal fluctuation range in the stable signal state. The key frequency energy value read at the 26th ms drops to 40 dB, and the absolute difference from the key frequency energy value read at the 25th ms is 65 dB, which is greater than the proportional tolerance limit of 20 dB, indicating that an abnormal fluctuation immediately generates a spectrum contradiction event.

[0109] Suppose the following sequence appears continuously: 100→115→95→120→80 (dB), the absolute difference of adjacent changes is 15→20→25→40 (dB) in turn, if the set current continuity threshold is 30 dB (100 dB X 30%), 15 dB, 20 dB, 25 dB do not exceed the continuity threshold, but 40 dB exceeds the continuity threshold, combined with the existing multi-jump shock characteristics also produces a spectrum conflict event. The normal use scenario should be a slow fluctuation sequence of 100→103→105→102 (dB).

[0110] In one embodiment of the present application, step S5 comprises the following steps:

[0111] When the flag signal of the steady-state maintenance event output by step S3 changes to the inactive state, the energy decay pattern of the signal capture end phase generates an orderly termination event.

[0112] Specifically, when the flag signal of the steady-state maintenance event changes to the inactive state, it is the instantaneous switching point of the output logic trigger signal from high level to low level, which is the starting trigger signal monitored by step S5. The processing unit starts to capture the energy intensity sequence of the original signal of step S1 as the observed object, and the final energy intensity value at the end time of the steady-state maintenance event is the decay starting reference line, which is the reference measurement value of the decay start. The new energy intensity value obtained in each unit time interval is continuously tracked, and the unit time interval refers to the fixed micro time unit for energy intensity sampling, which is consistent with the sampling time interval of step S1.

[0113] Each time an updated reading is obtained, the difference between the new energy intensity value and the previous recorded value in the current decay period is calculated to ensure that the difference is continuously negative and its absolute value is within the allowed step-down range interval consisting of the lower limit of the unit drop and the upper limit of the unit drop. The lower limit of the unit drop refers to the minimum energy drop allowed in a single measurement interval during the orderly decay process, and the upper limit of the unit drop refers to the maximum energy drop allowed in a single measurement interval during the orderly decay process. The lower limit and upper limit of the unit drop are obtained by statistically distributing the single-step drop value of the continuous hundreds of times when the real operation key is released, taking the lowest percentile value as the lower limit and the highest percentile value as the upper limit.

[0114] The synchronous start decay duration timer requires all consecutive recorded drop values to be step compliant until the termination decision value is reached, which is the energy intensity reference that the energy decay reaches a relatively stable state, usually set as the average intensity value of the background noise plus a small safety margin (usually set as 2-5dB). Only when the total length of time experienced throughout the entire drop process is between the set minimum complete decay duration and the maximum reasonable decay duration, and ≤3 non-consecutive abnormal points are allowed throughout the process, a flag signal of an orderly termination event is generated. The flag signal of the orderly termination event is a logical confirmation signal sent after confirming the morphological features of the drop process throughout the entire process.

[0115] The minimum complete decay duration is the minimum duration statistical value required for the effective operation to complete the release, and the maximum reasonable decay duration is the maximum duration statistical value required for the effective operation to complete the release, which are respectively taken from the low percentile point and the high percentile point of the measured effective operation release time distribution.

[0116] For example, at the moment when the flag signal of the steady state maintenance event changes from 1 to 0, the current energy intensity is recorded as the initial value 100dB. Sampling is continuously performed at fixed intervals: the first newly measured value is 98dB (2dB lower than the previous value); the next reading is 95dB (single step drop of 3dB); and the subsequent sequence is 91→87→82→78→73dB (each time 4-5dB is dropped). After 7 consecutive drop processes, 73dB is reached (higher than the preset termination decision value 70dB), and monitoring is continued; the 8th measurement is 65dB (8dB lower than the preset dB drop amplitude upper limit 7dB), and the determination process is immediately interrupted and not passed.

[0117] Another normal case: after starting from 100dB, 98→95→91→86→80→73→65→60→55→50dB (all meet the single step drop of 2-6dB) appear in succession, and the 12th measurement is 48dB, which reaches the termination decision value 50dB range. At this time, the timer shows that the total time consumption is 480ms, which is within the preset effective window of 250-600ms, and an orderly termination event is immediately output.

[0118] The single step drop amplitude is set according to the fact that 90% of the single step drop values measured in the physical key release are between 2-6dB, so the lower limit is set to 1.5dB and the upper limit is set to 7dB; the time window 250ms is taken from the fastest release operation 220ms, and 600ms is based on the slowest release operation 550ms extended value; the termination decision value 50dB is determined by referring to the stable background noise average value 45dB and floating 11%.

[0119] In one embodiment of the present application, step S6 includes the following steps:

[0120] The logical order of the verification event chain is that the jump start event must precede the steady state holding event, the steady state holding event must precede the orderly termination event, and the spectrum contradiction event, if present, forces the interruption of the verification process. When all timing conditions are met and there is no spectrum contradiction event, the signal of valid control operation sequence is determined.

[0121] Specifically, the processing unit establishes an event state register to record the occurrence state and the respective accurate time stamp of the flag signal of the jump start event in step S2, the flag signal of the steady state holding event in step S3, the flag signal of the spectrum contradiction event in step S4, and the flag signal of the orderly termination event in step S5. The event state register refers to a specially opened storage space for recording the logical state of the event trigger signal generated in each independent step and the accurate microsecond-level timing mark. The value of the accurate time stamp refers to the absolute time count recorded at the moment of the effective change of the event flag signal using the high-precision timer of the system. The flag signal of the orderly termination event in step S5 is set or the preset timeout monitoring period is over after its occurrence, and the timing logic verification process is immediately started. The timing logic verification process refers to a running program for comparing the time sequence of multiple events according to the predetermined rules.

[0122] First, it is checked whether the event state register has the flag signal of the spectrum contradiction event. If yes, the verification is immediately interrupted and all temporary states are cleared. Under the condition that there is no spectrum contradiction, the time stamp values of the three key events are extracted from the event state register in sequence: the jump start event occurrence time point, the steady state holding event start time point, and the orderly termination event occurrence time point. It is verified that the jump start occurrence time point value is less than the steady state holding start time point value; and the steady state holding start time point value is less than the orderly termination occurrence time point value; and the time difference between the steady state holding occurrence time point and the orderly termination occurrence time point needs to be within the reasonable interval between the preset minimum behavior continuation period and the maximum operation duration.

[0123] The minimum behavior continuation period refers to the minimum time length threshold required from the steady state holding start to the orderly termination, which is determined according to the most basic mechanical action that cannot be omitted in the operation process and the physical time delay of the circuit response. The maximum operation duration refers to the upper limit of the duration allowed for a complete operation, which is determined by referring to the slowest process of the natural decay of the signal energy to the recognition boundary value. Only when all conditions are met synchronously, the signal of valid control operation sequence is determined, and a verification pass instruction is sent to the execution unit. The minimum behavior continuation period sets a lower limit value according to the basic time consumption characteristics of physical operation, and the maximum operation duration sets an extension value according to the upper limit of the effective operation duration. The execution unit refers to the physical driving device that is actually responsible for switching the communication channel or turning on the transmitting circuit in the intercom system.

[0124] For example, the current event status register state is: 15:00:00.000 record jump start event; 15:00:00.500 record steady state holding event; 15:00:01.000 record ordered termination event; the spectrum contradiction event flag is always 0. After the timing verification is started: first confirm no contradiction event; extract time stamp comparison: 00.000 < 00.500 (satisfy start before steady state); 00.500 < 01.000 (satisfy steady state before termination); calculate time difference (01.000-00.500) = 500ms, the value is in the preset reasonable interval of 200ms-800ms, output the signal of valid control operation sequence. If there is a spectrum contradiction flag (such as value 1) in the event status register, it is directly determined to be invalid regardless of other time stamp matching conditions.

[0125] In another example, the timing is: jump event 00:00.000, steady state event 00:00.400, and termination event 00:00.900 (time difference 500ms conforms to the interval), but a spectrum contradiction flag is found, and it is immediately determined to be invalid.

[0126] For example, the time stamp sequence is: jump 00:00.000, steady state 00:00.300, and ordered termination 00:00.200 (00.300>00.200 violates the sequence), even if there is no contradiction event, it is determined to fail. The shortest behavior duration 200ms is set according to the following: experiments show that the mechanical reaction from the start of the steady state to the release of the key at least needs 180ms; the maximum duration 800ms covers the measured slowest release process of 750ms.

[0127] In one embodiment of the application, step S7 comprises the following steps:

[0128] Only after the signal of valid control operation sequence is verified, the corresponding channel switching or talk control instruction of the intercom is executed. The signal of valid control operation sequence is the final logical confirmation flag signal output by step S6 after all timing conditions are verified, and the state change is the only criterion for triggering this step.

[0129] Specifically, the processing unit continuously monitors the state change of the signal of valid control operation sequence output by step S6, and when the event status register records the logical jump from the non-confirmation state to the valid confirmation state of the signal, the processing unit immediately transmits a preset format instruction trigger signal to the execution unit of the intercom system. The trigger signal generates corresponding instruction content according to the operation type code corresponding to the jump start event occurrence point recorded by the event status register, and the instruction trigger signal is a physical level signal with standard electrical characteristics and protocol format, which can directly drive the intercom hardware interface circuit to perform corresponding operations.

[0130] The control instruction transmission is strictly subject to the execution precondition of the final verification pass in step S6. If step S6 does not output a valid confirmation signal, any control action is prohibited regardless of other intermediate event characteristics.

[0131] The control instruction transmission is a one-time trigger mechanism that requires waiting for the system to complete resetting before responding to subsequent operation procedures. System complete resetting refers to automatically clearing all temporary data in the event state register and restarting the initialization process of signal monitoring after the entire detection procedure is completed.

[0132] The operation type distinguishing code is an implicit information code parsed from the initial energy jump characteristic detected in step S2. The encoding rule is predefined based on the exclusive fingerprint differences at key frequency points when different types of operations are started, and is used to distinguish different operation intentions such as channel switching or talk control. The exclusive energy characteristic differences at key frequency points (such as 410 MHz) for different control operations (such as channel switching / PTT talk) are set as follows: By collecting hundreds of physical button operation samples, the short-time peak characteristic specific to channel switching operation and the medium gradual characteristic of PTT operation are counted. Channel switching operation presents a high-intensity short-time peak (typical value: single pulse energy jump > 50 dB and pulse width < 3 ms within 20 ms) due to the short contact of mechanical buttons, and its binary code is set to 0x01. PTT talk operation requires stable triggering of the circuit and presents a medium-amplitude step-by-step gradual change (typical value: cumulative jump > 30 dB within 50 ms and containing multiple harmonic components), and its binary code is set to 0x02. The encoding rule is hard-coupled with the instruction protocol of the execution unit to achieve precise operation distinction.

[0133] For example, assuming that the signal of the valid control operation sequence generated by step S6 in the current event state register changes from logic 0 to 1 (confirmation state), and the associated operation type distinguishing code value in the event state register is the channel switching code, the processing unit immediately sends a channel switching trigger signal (such as a 20-millisecond high-level pulse output at a specific pin) to the execution unit. After receiving the signal, the execution unit drives the relay to switch to the target channel.

[0134] If the operation type distinguishing code in the event state register is the talk control code, a talk start trigger signal (such as another pin being continuously high) is sent. If the signal in step S6 is always maintained in the 0 state (such as due to the existence of a spectrum conflict event or a timing error leading to a verification failure), even if the steps S1-S5 all trigger events, the processing unit will not generate any instruction signal. After the instruction sending is completed, the system automatically resets all flag bits and the cached data of the event state register, and is ready to monitor the next signal input. The coding rule of the operation type distinguishing code is pre-defined as follows: the channel switching operation is a short and high-intensity spike (typical value: single pulse energy jump > 50 dB and pulse width < 3 ms within 20 ms) due to the short contact of the mechanical key, and the binary code thereof is set to 0x01; the PTT talk operation is a medium-amplitude step change (typical value: cumulative jump > 30 dB within 50 ms and containing multiple harmonic components) due to the stable trigger circuit, and the binary code thereof is set to 0x02.

[0135] Referring to the accompanying drawings Fig. 2 The application further provides a talkback control signal anti-interference system, comprising the following modules.

[0136] A signal dynamic monitoring module is configured to acquire an original signal of a talkback channel and monitor a dynamic change value of signal energy in real time.

[0137] A jump event trigger module is configured to trigger a jump start event when an energy jump feature of instantaneous surge in the original signal is identified.

[0138] A steady state event generation module is configured to track a subsequent energy stable state of the signal after the jump start event occurs, and generate a steady state holding event when a smooth intensity of the signal maintained within a preset fluctuation allowable boundary reaches a preset continuous holding reference time length.

[0139] A spectrum conflict detection module is configured to analyze an energy evolution trajectory of a preset key frequency point during the existence of the steady state holding event, and record a spectrum conflict event when a non-coherent fluctuation or a sudden drop amplitude of the preset key frequency point exceeds a preset proportional tolerance limit.

[0140] A decay pattern capture module is configured to capture an energy decay pattern at an end stage of the signal and generate an orderly termination event.

[0141] An event chain verification module is configured to verify the logical sequence of the event chain: the jump start event precedes the steady state holding event, the steady state holding event precedes the orderly termination event, and there is no spectrum conflict event, so as to determine an effective control operation sequence.

[0142] An instruction execution control module is configured to execute a talkback corresponding channel switching or talk control instruction only when the effective control operation sequence verification is passed.

[0143] It should be noted that the above formulas can be translated into unitless standard values or same-dimension superimposable parameters by the principle of dimensional consistency and mathematical standardization means (such as normalization processing, dimensionless parameter conversion or unit system unification), so as to eliminate the interference of different dimensions on the operation logic, make the formula have mathematical operation rationality and objective law adaptability while preserving the original data distribution characteristics. The above is only an exemplary embodiment of the present application, and cannot limit the scope of the present application.

[0144] The various modules can be implemented by software, hardware and their combination, and support hardware forms embedded in or independent of the processor in the computer device, and also support software forms stored in the memory in the computer device, so as to facilitate the processor to call and execute the operations corresponding to the various modules.

[0145] It should be noted that the human information (including but not limited to human device information and personal information, etc.) and data (including but not limited to data for analysis, stored data and displayed data, etc.) involved in the present application are information and data authorized by the human body or fully authorized by all parties. The collection, use and processing of relevant data require relevant legal standards.

[0146] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A method for anti-interference of intercom control signals, characterized in that: The following steps are involved: S1. Obtain the original signal of the intercom channel and monitor the dynamic change value of the signal energy in real time; S2. triggering a jump start event when identifying an energy jump feature that meets the requirements of an instantaneous sudden increase in the original signal; S3, after the jump start event occurs, tracking the subsequent energy stability state of the signal, and generating a steady-state maintenance event when it is detected that the signal maintains a stable intensity within a preset fluctuation allowable boundary for a preset continuous maintenance reference time length; S4. During the duration of the steady-state maintenance event, analyzing the energy evolution trajectory of the preset key frequency point, and recording a spectrum conflict event when detecting that the preset key frequency point has incoherent fluctuations or a sudden drop in amplitude exceeding a preset proportional tolerance limit; S5, capturing the energy decay pattern at the end of the signal and generating an orderly termination event; S6. Verify the logical order of the event chain: if the jump start event precedes the steady-state holding event, the steady-state holding event precedes the orderly termination event, and there is no spectrum conflict event, it is determined to be a valid control operation sequence; S7. Only after the valid control operation sequence is verified, the channel switching or voice control command corresponding to the intercom is executed.

2. The intercom control signal anti-interference method according to claim 1, characterized in that: Obtaining the original signal of the intercom channel includes the following steps: Connect to the preset communication channel of the intercom through the hardware receiving circuit to collect the energy intensity of the carrier signal; The energy intensity is quantitatively sampled according to a preset sampling time interval to obtain a time series numerical flow reflecting the energy size. The time series numerical flow refers to a data flow formed by arranging the energy intensity digital values ​​obtained by quantitative sampling in chronological order; Calculate the absolute difference in energy intensity between adjacent sampling points and output the dynamic change value of signal energy.

3. The anti-interference method for control signals of an intercom according to claim 1, characterized in that: Triggering a jump start event includes the following steps: The dynamic change value of the continuously output signal energy is used as the basic data source, and a preset time window greater than the preset sampling time interval is set; Accumulate the dynamic change values ​​of all signal energies within the preset time window to generate the window dynamic change cumulative value; When the cumulative value of the window dynamic change exceeds the preset steep rise reference value and the maximum single dynamic change value in the window reaches the preset minimum jump requirement, a jump start event is triggered.

4. The anti-interference method for intercom control signals according to claim 1, characterized in that: Generate a steady-state hold event, including the following steps: After the flag signal of the jump start event is triggered, the processing unit immediately starts a new round of monitoring window for the dynamic change value of the signal energy. The new round of monitoring window for the dynamic change value of the signal energy continues to slide and track the dynamic change value of each subsequent signal energy; When the continuous monitoring duration reaches the preset continuous maintenance benchmark duration, verify that all dynamic change values ​​are within the preset fluctuation allowable limit; If it is verified that all dynamic change values ​​are within the preset fluctuation allowable limit, a steady-state hold event is generated; if it is detected that the dynamic change value of any signal energy exceeds the fluctuation allowable limit, the accumulated time is immediately cleared and the inspection process is reset.

5. The intercom control signal anti-interference method according to claim 1, characterized in that: Recording spectrum conflict events includes the following steps: While the flag signal of the steady-state holding event is in an active state, the processing unit activates the fast Fourier transform co-processing module to perform frequency division processing on the output original signal and extract the energy value sequence of the preset key frequency points; Each time a new key frequency energy value reading is obtained, the absolute difference between it and the previous reading is calculated; When judging whether the absolute difference exceeds the proportional tolerance limit set based on the current stability strength reference value or detecting multiple consecutive jump changes greater than the preset continuity threshold, a spectrum contradiction event will be immediately generated if any abnormal fluctuation is detected.

6. The intercom control signal anti-interference method according to claim 1, characterized in that: Generate an orderly termination event, including the following steps: When the flag signal of the steady-state hold event changes to the inactive state, that is, the instantaneous switching point when the output logic trigger signal changes from high level to low level, the final energy intensity value at the end of the steady-state hold event is used as the attenuation starting point baseline, that is, the benchmark measurement value for the start of attenuation; Each time an updated reading is obtained, the difference between the new energy intensity value and the previous recorded value within the current decay period is calculated; It continues to be negative and its absolute value is within the allowable decline step range formed by the preset lower limit and upper limit of the unit decline, and the total decay time is between the preset shortest complete decay time and the longest reasonable decay time, until the detection energy intensity stabilizes to the termination judgment value close to the background noise level, and an orderly termination event is generated.

7. The intercom control signal anti-interference method according to claim 1, characterized in that: Verify the logical sequence of the event chain, including the following steps: Create an event status register containing the timestamp of each event; The event status register is a specially opened storage space used to record the logical status of the event trigger signal generated by each independent step and its precise microsecond timing mark in real time; The value of the timestamp refers to the absolute time count value recorded by the system's high-precision timer at the moment the event flag signal effectively changes; Force interruption of verification when spectrum contradiction event marker is detected; When there is no spectrum conflict event, verify that the jump start event timestamp is less than the steady-state maintenance event timestamp and less than the orderly termination event timestamp, and the duration from steady-state maintenance to orderly termination is within the preset reasonable operation duration range.

8. The intercom control signal anti-interference method according to claim 7, characterized in that: Determining a valid control operation sequence includes the following steps: Verify that the jump start time value is less than the steady-state start time value; and the steady-state start time value is less than the orderly termination time value; The time difference between the point when steady state maintenance occurs and the point when orderly termination occurs must be within a reasonable range defined between the preset minimum behavior duration and the maximum operation duration; Only when all conditions are met synchronously are the signals constituting a valid sequence of control operations determined.

9. The intercom control signal anti-interference method according to claim 1, characterized in that: Executing the corresponding channel switching or voice control command of the intercom includes the following steps: When the valid control operation sequence is verified to be passed, a preset operation type distinguishing code associated with the jump start event is extracted; Generate a channel switching or voice control command trigger signal based on the operation type discrimination code; Sends an instruction trigger signal to the execution unit.

10. A walkie-talkie control signal anti-interference system, characterized in that: Includes the following modules: Signal dynamic monitoring module, used to obtain the original signal of the intercom channel and monitor the dynamic change value of the signal energy in real time; A jump event triggering module is used to trigger a jump start event when identifying an energy jump feature that meets the instantaneous sudden increase in the original signal; A steady-state event generation module, which tracks the subsequent energy stability of the signal after the jump start event occurs, and generates a steady-state maintenance event when it detects that the signal maintains a stable intensity within a preset fluctuation allowable boundary for a preset continuous maintenance reference time length; A spectrum conflict detection module analyzes the energy evolution trajectory of a preset key frequency point during the duration of the steady-state maintenance event, and records a spectrum conflict event when it detects that the preset key frequency point has incoherent fluctuations or a sudden drop in amplitude exceeding a preset proportional tolerance limit; The decay shape capture module is used to capture the energy decay shape of the signal at the end stage and generate an orderly termination event; The event chain verification module verifies the logical order of the event chain: when the jump start event precedes the steady-state holding event, the steady-state holding event precedes the orderly termination event, and there is no spectrum conflict event, it is determined to be a valid control operation sequence; The command execution control module executes the channel switching or voice control command corresponding to the intercom only after the valid control operation sequence is verified.

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