Signal state detection circuit based on square wave frequency difference and detection method thereof

Abstract

The invention discloses a signal state detection circuit based on square wave frequency difference and a detection method thereof.The circuit comprises an XOR gate circuit and a band-pass filter, the first input end of the XOR gate circuit is used for inputting a first square wave signal A, and the second input end of the XOR gate circuit is used for inputting a second square wave signal B; the first square wave signal A and the second square wave signal B are square wave signals with different frequencies, and the output end of the XOR gate circuit is connected with the input end of the band-pass filter. The AND gate circuit not only inherits the advantages of simple structure and easy implementation of a traditional AND gate, but also remarkably enhances the anti-interference capability and safety in the logical operation process by introducing a frequency difference detection mechanism, and effectively avoids logical errors caused by interference. In addition, the invention also has good integration and compatibility, and can be easily integrated into a chip design and expanded into the existing electronic system.

Description

Technical Field

[0001] The present invention belongs to the technical field of logic circuit design, and particularly relates to a signal state detection circuit based on square wave frequency difference and a detection method thereof. Background Art

[0002] The AND logic unit is an indispensable basic building block in digital logic design and applications, and is widely used in integrated circuits, computer systems, and various digital signal processing devices. The function of the AND logic is to determine whether to generate a specific output signal by judging the states of the input signals. The traditional design of the AND logic unit is mainly based on the basic cell library of integrated circuits, and the AND gate circuit under the CMOS process is one of the most common implementation forms. The traditional CMOS AND gate circuit realizes the AND logic function through the cooperation of the pull-up and pull-down networks and inverters. However, in the existing integrated circuit design, the implementation of the AND logic usually depends on the AND gate circuit of the basic cell. Although these traditional AND gates have the advantages of simple structure, fast response, and low power consumption, they show obvious limitations in the application scenarios with high safety standards. Especially in key fields such as rail transit, aerospace, and medical equipment, the safety and reliability of the system are crucial. Due to their inherent physical characteristics, traditional AND gates may cause incorrect flips or failures of the logic states due to factors such as electromagnetic interference, temperature changes, or power supply fluctuations, thereby affecting the correctness and stability of signal transmission. In addition, in the board-level design, although a transformer-based secure AND gate solution has been developed to enhance the anti-interference ability of the system, such a solution has the defect of being difficult to miniaturize and integrate, so it cannot be applied to the field of modern integrated circuit design. Summary of the Invention

[0003] To solve the above problems, the present invention provides a signal state detection circuit based on square wave frequency difference and a detection method thereof, so as to solve the problem that the traditional AND logic gate circuit is easily affected by factors such as electromagnetic interference, temperature changes, or power supply fluctuations, resulting in incorrect flips or failures of the logic states, thereby affecting the correctness and stability of signal transmission.

[0004] A signal state detection circuit based on square wave frequency difference includes: an exclusive OR gate circuit and a band-pass filter; The first input terminal of the exclusive OR gate circuit is used to input a first square wave signal A, the second input terminal of the exclusive OR gate circuit is used to input a second square wave signal B, the first square wave signal A and the second square wave signal B are square wave signals with different frequencies, and the output terminal of the exclusive OR gate circuit is connected to the input terminal of the band-pass filter.

[0005] According to a specific embodiment of the present invention, the first input terminal and the second input terminal of the exclusive OR gate circuit are respectively connected to a first square wave signal source and a second square wave signal source.

[0006] According to a specific embodiment of the present invention, a first square wave signal source is used to generate a first square wave signal A, and a second square wave signal source is used to generate a second square wave signal B.

[0007] A signal state detection chip based on the square wave frequency difference includes the above-mentioned signal state detection circuit based on the square wave frequency difference.

[0008] A signal state detection product based on the square wave frequency difference includes the above-mentioned signal state detection chip based on the square wave frequency difference.

[0009] A signal state detection method based on the square wave frequency difference is based on the above-mentioned signal state detection circuit based on the square wave frequency difference, and is characterized by including: Obtain the first square wave signal A and the second square wave signal B in real time; Input the first square wave signal A and the second square wave signal B into an exclusive-OR gate circuit respectively to generate an intermediate node signal C; Input the intermediate node signal C into a band-pass filter for filtering to obtain a difference frequency signal D; Perform spectrum analysis on the difference frequency signal D, and detect the signal states of the first square wave signal A and the second square wave signal B based on the spectrum analysis result.

[0010] According to a specific embodiment of the present invention, performing spectrum analysis on the difference frequency signal D and detecting the signal states of the first square wave signal A and the second square wave signal B based on the spectrum analysis result includes: Perform spectrum analysis on the difference frequency signal D to obtain the frequency characteristics of the difference frequency signal D; Detect the signal states of the first square wave signal A and the second square wave signal B based on the frequency characteristics.

[0011] According to a specific embodiment of the present invention, further detecting the signal states of the first square wave signal A and the second square wave signal B based on the frequency characteristics includes: Judge whether the difference frequency signal D meets a preset difference frequency threshold standard based on the frequency characteristics. If it meets, judge that the signal states of the first square wave signal A and the second square wave signal B are normal. Otherwise, judge that the signal state of the first square wave signal A and / or the second square wave signal B is abnormal.

[0012] According to a specific embodiment of the present invention, the first square wave signal A and the second square wave signal B are square wave signals with different frequencies.

[0013] According to a specific embodiment of the present invention, the method further includes: generating the first square wave signal A based on the first square wave signal source, and generating the second square wave signal B based on the second square wave signal source.

[0014] Compared with the prior art, a signal state detection circuit based on the square wave frequency difference and its detection method provided by the present invention have the following advantages: 1. The present invention introduces a logic judgment mechanism based on the square wave frequency difference. By measuring and analyzing the difference frequency between two square wave signals, it realizes the effective detection of the input signal state. Compared with the traditional AND gate circuit, the present invention can ensure that when the input signal is abnormal, the activation of the lower-level circuit is effectively blocked, significantly enhancing the anti-interference ability and security during the logic operation process. Even in a highly interfering environment, the present invention can ensure the correct transmission of data signals, thus avoiding system insecurity caused by abnormal input signals. This mechanism provides a solid physical basis for the security and reliability of the system, especially suitable for application scenarios with extremely high requirements for security.

[0015] 2. By real-time dynamically monitoring and evaluating the frequency characteristics of the signal, the present invention can quickly and accurately judge whether the input signal is normal, replacing the traditional static level voltage detection method and transforming the traditional static working voltage detection into dynamic frequency detection, thus avoiding the risk of abnormal locking of the static working voltage caused by circuit short circuit or open circuit.

[0016] 3. The circuit structure of the present invention is not only simple and efficient but also has good integratability and compatibility. It is easy to integrate into chip design and expand to existing electronic systems, and can flexibly adapt to the upgrade requirements of existing electronic systems, providing a new solution for achieving a higher level of security and logic operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 is a circuit diagram for signal state detection based on the square wave frequency difference according to an embodiment of the present invention.

[0019] Figure 2 is a structural diagram of a traditional AND gate logic circuit according to an embodiment of the present invention.

[0020] Figure 3 is a flowchart of a method for signal state detection based on the square wave frequency difference according to an embodiment of the present invention.

[0021] Figure 4 is a flowchart of a method for judging the input signal state based on spectrum analysis according to an embodiment of the present invention.

[0022] Figure 5It is a waveform diagram of an input signal and an output signal under normal conditions provided according to an embodiment of the present invention.

[0023] Figure 6 It is a spectrogram of an input signal and an output signal under normal conditions provided according to an embodiment of the present invention.

[0024] Figure 7 It is a waveform diagram of an input signal and an output signal under abnormal conditions provided according to an embodiment of the present invention.

[0025] Figure 8 It is a spectrogram of an input signal and an output signal under abnormal conditions provided according to an embodiment of the present invention.

[0026] Figure 9 It is a waveform diagram of an output signal under normal conditions provided according to an embodiment of the present invention.

[0027] Figure 10 It is a spectrogram of an output signal under normal conditions provided according to an embodiment of the present invention.

[0028] Figure 11 It is a waveform diagram of an output signal under abnormal conditions provided according to an embodiment of the present invention.

[0029] Figure 12 It is a spectrogram of an output signal under abnormal conditions provided according to an embodiment of the present invention.

[0030] Reference numerals: 01 - Exclusive - OR gate circuit; 02 - Band - pass filter. Detailed implementation manners

[0031] In order to enable those skilled in the art to more clearly understand the concepts and ideas of the present invention, the present invention will be described in detail below in conjunction with specific embodiments. It should be understood that the embodiments given herein are only a part of all possible embodiments of the present invention. After reading the specification of this application, those skilled in the art are capable of making improvements, modifications, or substitutions to part or all of the following embodiments, and these improvements, modifications, or substitutions are also included within the scope of protection required by the present invention.

[0032] In this text, terms such as "first", "second" and other similar words are not intended to imply any order, quantity or importance, but are merely used to distinguish different elements. In this text, terms such as "a", "an" and other similar words are not intended to mean that there is only one thing, but rather that the relevant description only refers to one of the things, and the thing may have one or more. In this text, terms such as "comprising", "including" and other similar words are intended to represent a logical relationship, and should not be regarded as representing a spatial structure relationship. For example, "A includes B" is intended to mean that logically B belongs to A, rather than meaning that B is located inside A spatially. Additionally, the meanings of terms such as "comprising", "including" and other similar words should be regarded as open-ended, rather than closed. For example, "A includes B" is intended to mean that B belongs to A, but B does not necessarily constitute the whole of A, and A may also include other elements such as C, D, E, etc.

[0033] In this text, terms such as "embodiment", "the present embodiment", "an embodiment", "one embodiment" do not mean that the relevant description only applies to a specific embodiment, but rather that these descriptions may also apply to one or more other embodiments. Those skilled in the art should understand that in this text, any description made for a certain embodiment can be substituted, combined, or otherwise combined with the relevant descriptions in one or more other embodiments, and the new embodiments generated by substitution, combination, or other combination are easily conceivable by those skilled in the art and fall within the protection scope of the present invention.

[0034] Embodiment 1 Additional aspects and advantages of the embodiments of the present invention will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of the embodiments of the present invention. In combination with Figure 1 , an embodiment of the present invention provides a signal state detection circuit based on the square wave frequency difference, including: An exclusive-OR gate circuit 01 and a band-pass filter 02. The first input terminal and the second input terminal of the exclusive-OR gate circuit 01 are respectively connected to a first square wave signal source and a second square wave signal source. The first square wave signal source is used to generate a first square wave signal A, and the second square wave signal source is used to generate a second square wave signal B. The first input terminal of the exclusive-OR gate circuit 01 is used to input the first square wave signal A, and the second input terminal of the exclusive-OR gate circuit 01 is used to input the second square wave signal B. The first square wave signal A and the second square wave signal B are square wave signals with different frequencies. The output terminal of the exclusive-OR gate circuit 01 is connected to the input terminal of the band-pass filter 02.

[0035] In the embodiment of the present invention, the first square wave signal source is used to generate the first square wave signal A, and the second square wave signal source is used to generate the second square wave signal B. The first square wave signal A and the second square wave signal B are square wave signals of different frequencies, and their phase relationship changes continuously over time. The XOR gate circuit 01 is used to process the first square wave signal A and the second square wave signal B, and output an intermediate node signal C. The intermediate node signal C is a complex waveform, and its frequency component is a combination of the input signal frequency, which contains the sum frequency and difference frequency components in the first square wave signal A and the second square wave signal B. Since the square wave itself contains high-order harmonics, the output intermediate node signal C will also contain these high-order harmonics. Subsequently, the intermediate node signal C is input into the bandpass filter 02, and the difference frequency component in the intermediate node signal C is screened out by the bandpass filter 02, and the difference frequency signal D is output. The purpose of using the bandpass filter 02 is to prevent the interference of low-frequency noise and reduce the influence of the sum frequency component and high-order harmonics in the input signal on signal processing. The output difference frequency signal D is used for real-time monitoring and spectrum analysis. The signal states of the first square wave signal A and the second square wave signal B can be determined according to the spectrum analysis results.

[0036] like Figure 2 The traditional CMOS AND gate circuit structure shown is composed of two stages of circuits connected in series: the first stage is a NAND gate composed of four MOS transistors, and the second stage is an inverter composed of two MOS transistors. The traditional CMOS AND gate circuit realizes the AND logic function through the synergy of the pull-up and pull-down networks and the inverter. In the traditional AND gate logic circuit, when any of the input signals A and B is abnormal, the output intermediate node signal C may directly drive the lower circuit, and fail to effectively identify and transmit the abnormal state of the B signal. If both signal A and signal B are interfered or fail, an uncontrollable signal data C will be output, so it is not suitable for application scenarios with high safety performance requirements. In the signal state detection circuit based on square wave frequency difference provided by the present invention, by introducing the frequency difference detection mechanism, the anti-interference ability and safety in the logic operation process are significantly enhanced. Even in a highly interfered environment, this solution can ensure the correct transmission of data signals and effectively avoid logical errors caused by interference. In addition, the present invention not only inherits the advantages of the traditional AND gate structure being simple and easy to implement, but also has good integrability and compatibility. It is easy to be integrated into chip design and expanded into existing electronic systems, providing a new solution for achieving a higher level of security and logical operations.

[0037] Example 2 Based on the signal state detection circuit based on square wave frequency difference provided in Example 1, the embodiment of the present invention further provides a signal state detection method based on square wave frequency difference, such as Figures 3 - 12 As shown, including: S1: Obtain the first square wave signal A and the second square wave signal B in real time.

[0038] S2: Input the first square wave signal A and the second square wave signal B into an exclusive - OR gate circuit respectively to generate an intermediate node signal C.

[0039] S3: Input the intermediate node signal C into a band - pass filter for filtering to obtain a difference - frequency signal D.

[0040] S4: Perform spectrum analysis on the difference - frequency signal D, and detect the signal states of the first square wave signal A and the second square wave signal B based on the spectrum analysis results.

[0041] In the embodiment of the present invention, before obtaining the first square wave signal A and the second square wave signal B, it further includes generating the first square wave signal A based on a first square wave signal source and generating the second square wave signal B based on a second square wave signal source. The first square wave signal A and the second square wave signal B are square wave signals with different frequencies, and the phase relationship between the first square wave signal A and the second square wave signal B changes continuously with time. Then, input the first square wave signal A and the second square wave signal B into an exclusive - OR gate circuit for signal processing to generate an intermediate node signal C. The intermediate node signal C contains the sum - frequency and difference - frequency components of the first square wave signal A and the second square wave signal B. Subsequently, input the intermediate node signal C into a band - pass filter 04, and filter out the difference - frequency component in the intermediate node signal C through the band - pass filter 04 to output a difference - frequency signal D. Then, input the difference - frequency signal D into a frequency detection unit to perform real - time monitoring and spectrum analysis on the signal state of the output difference - frequency signal D. By performing spectrum analysis on the difference - frequency signal D and detecting the signal states of the first square wave signal A and the second square wave signal B based on the spectrum analysis results. Compared with the traditional AND logic circuit, the present invention significantly enhances the anti - interference ability and security in the logic operation process by introducing a frequency - difference detection mechanism. Even in a highly interfering environment, this solution can ensure the correct transmission of data signals and effectively avoid logic errors caused by interference.

[0042] Specifically, step S4 performing spectrum analysis on the difference - frequency signal D and detecting the signal states of the first square wave signal A and the second square wave signal B based on the spectrum analysis results includes: S41: Perform spectrum analysis on the difference - frequency signal D to obtain the frequency characteristics of the difference - frequency signal D.

[0043] S42: Detect the signal states of the first square wave signal A and the second square wave signal B based on the frequency characteristics, specifically including: Judge whether the difference - frequency signal D meets a preset difference - frequency threshold standard based on the frequency characteristics. If it meets, judge that the signal states of the first square wave signal A and the second square wave signal B are normal; otherwise, judge that the signal state of the first square wave signal A and / or the second square wave signal B is abnormal.

[0044] In an embodiment of the present invention, by simulating the input signals in the normal working state and the input signals in the abnormal working state, the output signals in the normal working state and the output signals in the abnormal working state are correspondingly obtained. By analyzing the frequency characteristics of the output signals in the normal working state and the output signals in the abnormal working state, the signal states of the input signals in the normal working state and the abnormal working state are judged.

[0045] In the normal working state, the first square wave signal A and the second square wave signal B are square wave signals with different frequencies, and the frequency difference between them is not large. The output waveform in the normal working state is as Figure 5 shown. The first square wave signal A and the second square wave signal B are periodic square waves, which can be regarded as being composed of a series of sine waves with different frequencies superimposed. The frequencies of these sine waves are integer multiples of the fundamental frequency of the square wave. When these two square wave signals with different frequencies pass through the exclusive-OR gate circuit, the output intermediate node signal C as a whole shows periodic changes, reflecting the bit-by-bit comparison result of these two input signals. The first square wave signal A, the second square wave signal B, and the intermediate node signal C are respectively subjected to spectrum analysis, and the spectrum analysis diagram as shown in Figure 6 is obtained. From Figure 6 it can be observed that the spectrum of the intermediate node signal C output through the exclusive-OR gate circuit not only contains the difference frequency signal, but also contains other frequency components, such as the sum frequency and other higher harmonic components, but the difference frequency component occupies an important position in the spectrum of the output signal. The reason is that the exclusive-OR operation simulates the phase comparison of two signals, and the result of the phase comparison is related to the frequency difference of the signals.

[0046] In the abnormal working state, assume that the first square wave signal A is a normal square wave signal, while the second square wave signal B is abnormal, showing a continuous constant high level. The output waveform in the abnormal working state is as Figure 7 shown. At this time, the intermediate node signal C output through the exclusive-OR gate shows the same waveform characteristics as the first square wave signal A. This phenomenon can be attributed to the working principle of the exclusive-OR gate. When one of the input signals is a constant level, the output of the exclusive-OR gate will change with the change of the other input signal. The first square wave signal A, the second square wave signal B, and the intermediate node signal C are respectively subjected to spectrum analysis, and the spectrum analysis diagram as shown in Figure 8 is obtained. Since the second square wave signal B is in a constant high level state, the spectrum analysis result shows that the frequency component is almost zero or shows a very low noise level. The waveforms of the first square wave signal A and the intermediate node signal C are the same, showing the same spectrum characteristics, mainly concentrated at the fundamental frequency of signal A, and this fundamental frequency is not within the preset difference frequency range. Although the intermediate node signal C in the abnormal working state has the same waveform as the A signal, its spectrum characteristics have changed significantly. This change in spectrum characteristics provides an important basis for subsequent frequency detection.

[0047] Figures 9 - 12 The waveforms and spectra of the difference frequency signal D output after the intermediate node signal C is processed by the band-pass filter in the normal working state and the abnormal working state are compared. In the normal working state, the difference frequency of the two input square wave signals is relatively stable. After being processed by the band-pass filter, only one obvious peak is shown in the spectrum of the output difference frequency signal D, indicating that only the signals near the preset frequency are filtered out. When any input signal fails, the system enters the abnormal working state. At this time, the frequency difference of the input signals increases significantly, resulting in the lack of the preset difference frequency component in the intermediate node signal C, so that an effective difference frequency signal cannot be obtained through the band-pass filter. The amplitude of the filtered output signal in the abnormal state is significantly lower, only a few tenths of the amplitude of the normal filtered output signal. This significant amplitude attenuation causes the signal to fail to reach the minimum threshold condition required to trigger the next-stage circuit, so it cannot effectively activate or drive the output response of the subsequent circuit. Based on this frequency characteristic, the present invention takes whether the preset frequency of the detected output signal exists as the judgment criterion for whether the input signal is normal.

[0048] Embodiment 3 Based on the signal state detection circuit based on the square wave frequency difference provided in Embodiment 1, the embodiment of the present invention further provides a signal state detection chip based on the square wave frequency difference, including the above-mentioned signal state detection circuit based on the square wave frequency difference.

[0049] Furthermore, the present invention also provides a signal state detection product based on the square wave frequency difference, including the above-mentioned signal state detection chip based on the square wave frequency difference.

[0050] In summary, a signal state detection circuit and its detection method based on the square wave frequency difference provided by the present invention have the following advantages: 1. The present invention introduces a logic judgment mechanism based on the square wave frequency difference. By measuring and analyzing the difference frequency between two square wave signals, the effective detection of the input signal state is realized. Compared with the traditional AND gate circuit, the present invention can effectively prevent the activation of the lower-level circuit when the input signal is abnormal, significantly enhancing the anti-interference ability and security in the logic operation process. Even in a highly interfering environment, the present invention can ensure the correct transmission of data signals, thus avoiding the system insecurity caused by abnormal input signals. This mechanism provides a solid physical basis for the security and reliability of the system, especially suitable for application scenarios with extremely high requirements for security.

[0051] 2. By dynamically monitoring and evaluating the frequency characteristics of signals in real time, the present invention can quickly and accurately determine whether the input signal is normal, replacing the traditional static level voltage detection method and transforming the traditional static operating voltage detection into dynamic frequency detection, thus avoiding the risk of abnormal locking of the static operating voltage caused by circuit short - circuit or open - circuit.

[0052] 3. The circuit structure of the present invention is not only simple and efficient, but also has good integratability and compatibility. It is easy to be integrated into chip design and extended to existing electronic systems, and can flexibly adapt to the upgrade requirements of existing electronic systems, providing a new solution for achieving higher - level security and logical operations.

[0053] The concepts, principles and ideas of the present invention have been described in detail above in combination with specific embodiments (including examples and instances). Those skilled in the art should understand that the embodiments of the present invention are not limited to the several forms given above. After reading the present application document, those skilled in the art can make any possible improvements, replacements and equivalent forms to the steps, methods, systems and components in the above - mentioned embodiments. These improvements, replacements and equivalent forms should be regarded as falling within the scope of the present invention, and the protection scope of the present invention is only determined by the claims.

Claims

1. A signal state detection circuit based on square wave frequency difference, characterized in that: include: XOR gate circuit and bandpass filter; The first input end of the XOR gate circuit is used to input a first square wave signal A, and the second input end of the XOR gate circuit is used to input a second square wave signal B. The first square wave signal A and the second square wave signal B are square wave signals of different frequencies, and the output end of the XOR gate circuit is connected to the input end of the bandpass filter.

2. The signal state detection circuit based on square wave frequency difference according to claim 1, characterized in that: The first input terminal and the second input terminal of the XOR gate circuit are connected to the first square wave signal source and the second square wave signal source respectively.

3. The signal state detection circuit based on square wave frequency difference according to claim 2, characterized in that: The first square wave signal source is used to generate a first square wave signal A, and the second square wave signal source is used to generate a second square wave signal B.

4. A signal state detection chip based on square wave frequency difference, characterized in that: It comprises the signal state detection circuit based on square wave frequency difference as claimed in claim 1.

5. A signal state detection product based on square wave frequency difference, characterized in that: It comprises the signal state detection chip based on square wave frequency difference as claimed in claim 4.

6. A signal state detection method based on square wave frequency difference, the method is based on the signal state detection circuit based on square wave frequency difference according to claim 1, characterized in that: include: Acquire a first square wave signal A and a second square wave signal B in real time; Inputting the first square wave signal A and the second square wave signal B into an XOR gate circuit respectively to generate an intermediate node signal C; Inputting the intermediate node signal C into a bandpass filter for filtering to obtain a difference frequency signal D; A spectrum analysis is performed on the difference frequency signal D, and signal states of the first square wave signal A and the second square wave signal B are detected based on the spectrum analysis result.

7. The signal state detection method based on square wave frequency difference according to claim 6, characterized in that: The performing spectrum analysis on the difference frequency signal D and detecting the signal states of the first square wave signal A and the second square wave signal B based on the spectrum analysis result comprises: Performing spectrum analysis on the difference frequency signal D to obtain the frequency characteristics of the difference frequency signal D; The signal states of the first square wave signal A and the second square wave signal B are detected based on the frequency characteristics.

8. The signal state detection method based on square wave frequency difference according to claim 7, characterized in that: The detecting the signal states of the first square wave signal A and the second square wave signal B based on the frequency characteristics further comprises: Based on the frequency characteristics, it is determined whether the difference frequency signal D meets the preset difference frequency threshold standard. If so, it is determined that the signal states of the first square wave signal A and the second square wave signal B are normal. Otherwise, it is determined that the signal states of the first square wave signal A and / or the second square wave signal B are abnormal.

9. The signal state detection method based on square wave frequency difference according to claim 6, characterized in that: The first square wave signal A and the second square wave signal B are square wave signals with different frequencies.

10. The signal state detection method based on square wave frequency difference according to claim 6, characterized in that: The method further includes: generating a first square wave signal A based on a first square wave signal source, and generating a second square wave signal B based on a second square wave signal source.

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