CN118295034A - Nonlinear node detection circuit and detection device - Google Patents
Nonlinear node detection circuit and detection device Download PDFInfo
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Abstract
The invention relates to a nonlinear node detection circuit and a nonlinear node detection device. The nonlinear node detection circuit includes: a fundamental wave signal generating unit, a transmitting antenna, a detection signal generating unit and a receiving antenna unit; the transmitting antenna is connected with the fundamental wave signal generating unit and is used for receiving the fundamental wave signal generated by the fundamental wave signal generating unit and transmitting the fundamental wave signal; the receiving antenna unit is used for receiving the second harmonic signal and/or the third harmonic signal corresponding to the fundamental wave signal; the detection signal generation unit is connected with the receiving antenna unit, and is used for generating a first detection signal corresponding to the second harmonic signal when the receiving antenna unit receives the second harmonic signal and generating a second detection signal corresponding to the third harmonic signal when the receiving antenna unit receives the third harmonic signal. The implementation of the invention can improve the detection sensitivity of the detection circuit, and greatly reduce the false alarm rate of detection while realizing remote detection.
Description
Technical Field
The invention relates to the technical field of detection, in particular to a nonlinear node detection circuit and a nonlinear node detection device.
Background
Nonlinear node detectors are used to search for hidden eavesdropping devices, detonating circuits, and other electronic devices that contain semiconductor elements. The device can be a wireless telephone, a microphone amplifier, a wired microphone, an infrared or ultrasonic data and control channel circuit, an audio recorder, a detonation circuit and the like, and can be accurately positioned no matter whether an inspection object is started, standby or shut down. The existing general detection circuit has the problems of low sensitivity, short detection distance, high false alarm rate and the like due to the defects of the radio frequency circuit.
Disclosure of Invention
The technical problem to be solved by the embodiment of the invention is to provide a nonlinear node detection circuit and a nonlinear node detection device aiming at the part of technical defects in the prior art.
The technical scheme adopted by the embodiment of the invention for solving the technical problems is as follows: a nonlinear node detection circuit is constructed, comprising: a fundamental wave signal generating unit, a transmitting antenna, a detection signal generating unit and a receiving antenna unit;
The transmitting antenna is connected with the fundamental wave signal generating unit and is used for receiving the fundamental wave signal generated by the fundamental wave signal generating unit and transmitting the fundamental wave signal;
the receiving antenna unit is used for receiving the second harmonic signal and/or the third harmonic signal corresponding to the fundamental wave signal;
The detection signal generation unit is connected with the receiving antenna unit, and is used for generating a first detection signal corresponding to the second harmonic signal when the receiving antenna unit receives the second harmonic signal and generating a second detection signal corresponding to the third harmonic signal when the receiving antenna unit receives the third harmonic signal.
Preferably, in the nonlinear node detection circuit according to the present invention, the receiving antenna unit includes a first receiving antenna, a second receiving antenna, and a first switching circuit;
the first receiving antenna is used for receiving the second harmonic signal and outputting the second harmonic signal, and the second receiving antenna is used for receiving the third harmonic signal and outputting the third harmonic signal;
The first switching circuit is connected with the first receiving antenna, the second receiving antenna and the detection signal generating unit and is used for switching the detection signal generating unit to receive the second harmonic signal or the third harmonic signal.
Preferably, in the nonlinear node detection circuit according to the present invention, the receiving antenna unit further includes a first high-pass filter and a first low-noise amplifier; the input end of the first high-pass filter is connected with the first receiving antenna, the output end of the first high-pass filter is connected with the input end of the first low-noise amplifier, and the output end of the first low-noise amplifier is connected with the first input end of the first switching circuit;
And/or the receiving antenna unit further comprises a second high pass filter and a second low noise amplifier; the input end of the second high-pass filter is connected with the second receiving antenna, the output end of the second high-pass filter is connected with the input end of the second low-noise amplifier, and the output end of the second low-noise amplifier is connected with the second input end of the first switching circuit.
Preferably, in the nonlinear node detection circuit of the present invention, the detection signal generation unit includes a mixing circuit, a detection signal output circuit, and a local oscillation signal output circuit;
The receiving antenna unit is used for receiving the second harmonic signal and the third harmonic signal;
The local oscillation signal output circuit is used for switching and outputting a first local oscillation signal or a second local oscillation signal to the mixing circuit;
The mixing circuit is connected with the local oscillation signal output circuit and the receiving antenna unit, and is used for receiving the first local oscillation signal and the second harmonic signal and mixing to generate a first mixing signal, and is used for receiving the second local oscillation signal and the third harmonic signal and mixing to generate a second mixing signal;
The detection signal output circuit is connected with the mixing circuit and is used for receiving the first mixing signal to generate the first detection signal and receiving the second mixing signal to generate the second detection signal.
Preferably, in the nonlinear node detection circuit of the present invention, the local oscillation signal output circuit includes a first frequency source, a frequency doubling circuit, and a second switching circuit;
the first output end of the first frequency source is used for outputting the first local oscillation signal;
the second output end of the first frequency source is used for outputting a third local oscillation signal;
the frequency doubling circuit is connected with the second output end of the first frequency source and is used for doubling the frequency of the third local oscillation signal to generate the second local oscillation signal;
The second switching circuit is connected with the first output end of the first frequency source, the frequency doubling circuit and the mixing circuit and is used for switching the mixing circuit to receive the first local oscillation signal or the second local oscillation signal.
Preferably, in the nonlinear node detection circuit according to the present invention, the frequency multiplier circuit includes a frequency multiplier, a third high-pass filter, and a third low-noise amplifier;
the input end of the frequency multiplier is connected with the second output end of the first frequency source, the output end of the frequency multiplier is connected with the input end of the third high-pass filter, the output end of the third high-pass filter is connected with the input end of the third low-noise amplifier, and the output end of the third low-noise amplifier is connected with the second switching circuit.
Preferably, in the nonlinear node detection circuit according to the present invention, the detection signal output circuit includes a first low-pass filter, a fourth low-noise amplifier, a crystal filter, and a power detector;
The input end of the first low-pass filter is connected with the output end of the mixing circuit, the output end of the first low-pass filter is connected with the input end of the fourth low-noise amplifier, the output end of the fourth low-noise amplifier is connected with the input end of the crystal filter, the output end of the crystal filter is connected with the input end of the power detector, and the output end of the power detector is used for outputting the first detection signal or the second detection signal.
Preferably, in the nonlinear node detection circuit according to the present invention, the receiving antenna unit further includes a fifth low noise amplifier;
The input end of the fifth low noise amplifier is connected with the output end of the first switching circuit, and the output end of the fifth low noise amplifier is connected with the detection signal generation unit.
Preferably, in the nonlinear node detection circuit according to the present invention, the fundamental wave signal generating unit includes a fundamental wave signal conditioning circuit and a second low-pass filter;
The fundamental wave signal conditioning circuit is used for generating and conditioning the fundamental wave signals, the input end of the second low-pass filter is connected with the output end of the fundamental wave signal conditioning circuit, and the output end of the second low-pass filter is connected with the transmitting antenna.
Preferably, in the nonlinear node detection circuit according to the present invention, the nonlinear node detection circuit further includes: the device comprises a main controller, a power supply, a first low-pass filter circuit and a second low-pass filter circuit;
The main controller is connected with the fundamental wave signal generating unit through the first low-pass filter circuit, and outputs a control signal to the fundamental wave signal generating unit through the first low-pass filter circuit;
The power supply is connected with the fundamental wave signal generating unit through the second low-pass filter circuit, and the power supply outputs a power supply to the fundamental wave signal generating unit through the second low-pass filter circuit.
The embodiment of the invention also constructs a nonlinear node detection device which comprises the nonlinear node detection circuit.
By implementing the nonlinear node detection circuit and the nonlinear node detection device, the detection sensitivity of the detection circuit can be improved by arranging the independent transmitting antenna and the independent receiving antenna, and the detection false alarm rate is greatly reduced while the remote detection is realized.
Drawings
The invention will be further described with reference to the accompanying drawings and examples, in which:
FIG. 1 is a block diagram of a nonlinear node detection circuit according to an embodiment of the present invention;
FIG. 2 is a block diagram of another embodiment of a nonlinear node detection circuit in accordance with the present invention;
FIG. 3 is a schematic circuit diagram of one embodiment of a nonlinear node detection circuit in accordance with the present invention;
fig. 4 is a schematic circuit diagram of an embodiment of a low pass filter circuit in a nonlinear node detection circuit in accordance with the present invention.
Reference numerals illustrate:
110: fundamental wave signal generation unit, 120: transmitting antenna, 130: a receiving antenna unit, 140: detection signal generation unit, 150: a main controller;
1311: first receive antenna, 1321: second receiving antenna, 133: first switching circuit, 1312: first high pass filter, 1313: first low noise amplifier, 1322: second high pass filter, 1323: a second low noise amplifier;
141: mixing circuit, 142: detection signal output circuit, 143: local oscillation signal output circuit 1432: first frequency source, 1430: frequency multiplier circuit 1431: second switching circuit 1433: frequency multiplier, 1434: third high pass filter, 1435: a third low noise amplifier;
1421: first low pass filter, 1422: fourth low noise amplifier, 1423: crystal filter, 1424: a power detector;
112: fundamental wave signal conditioning circuit, 111: a second low pass filter, 1123: second frequency source, 1122: numerical control attenuator, 1121: a power amplifier;
201. 202, 203: inductors, 204, 205: a capacitor.
Detailed Description
For a clearer understanding of the technical features, objects and effects of the present invention, a detailed description of embodiments of the present invention will be made with reference to the accompanying drawings.
As shown in fig. 1, in a first embodiment of a nonlinear node detection circuit of the present invention, a nonlinear node detection circuit (hereinafter, referred to as a "nonlinear node detection circuit" by "detection circuit") includes: a fundamental wave signal generating unit 110, a transmitting antenna 120, a detection signal generating unit 140, and a receiving antenna unit 130. The transmitting antenna 120 is connected to the fundamental wave signal generating unit 110 for receiving the fundamental wave signal generated by the fundamental wave signal generating unit 110 and transmitting the fundamental wave signal. And the receiving antenna unit 130 is configured to receive the second harmonic signal and/or the third harmonic signal corresponding to the fundamental wave signal. The detection signal generating unit 140 is connected to the receiving antenna unit 130, and is configured to generate a first detection signal corresponding to a second harmonic signal when the receiving antenna unit 130 receives the second harmonic signal, and to generate a second detection signal corresponding to a third harmonic signal when the receiving antenna unit 130 receives the third harmonic signal.
Specifically, in the detection circuit, a fundamental wave signal may be generated by the fundamental wave signal generating unit 110, and may be externally transmitted through the transmitting antenna 120. When the fundamental wave signal is transmitted to the detected area, the detected area may have an influence on the fundamental wave signal, for example, when an electronic device including a semiconductor is present in the detected area, a nonlinear node present in the semiconductor generates and radiates a second harmonic signal and a third harmonic signal corresponding to the fundamental wave signal under the action of the fundamental wave signal. It is understood that the second harmonic signal and the third harmonic signal mentioned in the embodiments of the present invention are the second harmonic signal and the third harmonic signal corresponding to the fundamental wave signal.
The detection circuit may receive the second harmonic signal or the third harmonic signal through the receiving antenna unit 130. In this embodiment, the receiving antenna unit 130 may receive only the second harmonic signal, only the third harmonic signal, or both the second harmonic signal and the third harmonic signal. The detection signal generating unit 140 is connected to the receiving antenna unit 130, and is configured to receive the second harmonic signal or the third harmonic signal. The detection signal generation unit 140, upon receiving the second harmonic signal, may generate a first detection signal corresponding to the second harmonic signal by performing corresponding signal processing on the second harmonic signal. The detection signal generation unit 140, upon receiving the third harmonic signal, may generate a second detection signal corresponding to the third harmonic signal by performing corresponding signal processing on the third harmonic signal.
It will be appreciated that both the first detection signal and the second detection signal may be used to characterize the probability of the presence of an electronic device in the detected area, and that a final detection result, which characterizes the presence of an electronic device in the detected area, may be obtained by determining or comparing the first detection signal and the second detection signal, respectively, based on the detection circuit. For example, in an embodiment, the main controller 150 may compare the signal strength of the first detection signal with a preset signal strength, and if the signal strength of the first detection signal is greater than the preset signal strength (the preset signal strength may be determined according to the second harmonic strength in the environment), it may be determined that the semiconductor device exists in the detected area, that is, it may be determined that the electronic device exists in the detected area, so that the detection of the electronic device may be implemented.
It should be noted that, in actual use, it is found that, besides the nonlinear node existing in the semiconductor, a type of metal rust node also exists to generate a second harmonic signal and a third harmonic signal, so that the detection circuit can also obtain a first detection signal and a second detection signal when the semiconductor does not exist in the detected area, and the false alarm rate of the detection device is higher. In an embodiment, since the inventor finds that the signal strength of the third harmonic signal generated by the metal corrosion node is greater than the signal strength of the second harmonic signal generated by the metal corrosion node, in this embodiment, the receiving antenna unit 130 may receive the second harmonic signal and the third harmonic signal, and further compare the first detection signal and the second detection signal to obtain a comparison result of the signal strength of the second harmonic signal and the third harmonic signal on the basis of obtaining the first detection signal and the second detection signal and confirming that the signal strength of the first detection signal is greater than the preset signal strength. When it is determined that the signal intensity of the first detection signal is higher than the signal intensity of the second detection signal, it is possible to determine that the detected region corresponds to a semiconductor device or an electronic device when it is determined that the signal intensity of the second harmonic signal is higher than the signal intensity of the third harmonic signal. When the signal intensity of the first detection signal is lower than that of the second detection signal, it can be determined that the signal intensity of the third harmonic signal is higher than that of the second harmonic signal, then it can be determined that the metal rust node corresponding to the detected area, that is, no electronic equipment exists in the detected area, and the false alarm rate of the detector can be reduced through the comparison process of the signal intensities.
In the detection circuit, since the transmitting antenna 120 and the receiving antenna unit 130 are respectively arranged to realize the transmitting function of the fundamental wave signal and the receiving function of the second harmonic signal and the third harmonic signal, compared with the scheme of adopting the same transmitting antenna to transmit the fundamental wave signal and the scheme of adopting the same transmitting antenna to receive the second harmonic signal and the third harmonic signal, the transmitting gain and the receiving gain of the transmitting antenna are substantially one antenna, and the transmitting gain and the receiving gain of the transmitting antenna and the receiving gain of the receiving antenna are limited due to the fact that the antenna design area on the same antenna board is limited, the transmitting gain and the receiving gain of the transmitting antenna in the traditional design scheme can not realize higher gain, and the nonlinear node detection circuit adopts the transmitting antenna 120 and the receiving antenna unit 130 which are respectively independent to realize the signal transmitting function and the receiving function respectively, and can not be influenced by each other in the aspect of the respective antenna design, so that the transmitting antenna 120 and the receiving antenna unit 130 can be respectively realized by adopting the antennas with higher gain, the performances of the transmitting antenna 120 and the receiving antenna unit 130 are better, and the signal receiving capability in the detection process can be beneficial to improving the detection sensitivity of the detection circuit. In one embodiment, the transmit antenna 120 may be a narrowband antenna that is used only for the transmission of fundamental signals in a particular frequency range.
Optionally, as shown in fig. 3, the receiving antenna unit 130 includes a first receiving antenna 1311, a second receiving antenna 1321, and a first switching circuit 133. The first receiving antenna 1311 is configured to receive and output a second harmonic signal, and the second receiving antenna 1321 is configured to receive and output a third harmonic signal. The first switching circuit 133 is connected to the first receiving antenna 1311, the second receiving antenna 1321, and the detection signal generating unit 140, and is configured to switch the detection signal generating unit 140 to receive the second harmonic signal or the third harmonic signal.
Specifically, in the receiving antenna unit 130, the above-described second harmonic signal may be received through the first receiving antenna 1311, and the above-described third harmonic signal may be received through the second receiving antenna 1321.
Under the switching action of the first switching circuit 133, the detection signal generating unit 140 may be turned on with the first receiving antenna 1311 or turned on with the second receiving antenna 1321 through the first switching circuit 133. The detection signal generation unit 140 may receive the second harmonic signal and generate a first detection signal according to the second harmonic signal when turned on with the first receiving antenna 1311. The detection signal generation unit 140 may receive the third harmonic signal and generate a second detection signal according to the third harmonic signal when turned on with the second receiving antenna 1321. The first switching circuit 133 may include a single pole double throw type radio frequency switch, among others. The first receiving antenna 1311 may employ a narrowband antenna corresponding to the second harmonic signal, and the second receiving antenna 1321 may employ a narrowband antenna corresponding to the third harmonic signal, so as to achieve the capability of detecting weak signals and improve the detection sensitivity. In the scheme, only one detection signal generating unit 140 is needed to process the second harmonic signal and the third harmonic signal through the switching action of the first switching circuit 133, so that the circuit structure is simplified, unnecessary noise is avoided being introduced, and the detection accuracy of the nonlinear node is improved.
Optionally, as shown in fig. 3, the receiving antenna unit 130 further comprises a first high pass filter 1312 and a first low noise amplifier 1313. An input end of the first high-pass filter 1312 is connected to the first receiving antenna 1311, an output end of the first high-pass filter 1312 is connected to an input end of the first low-noise amplifier 1313, and an output end of the first low-noise amplifier 1313 is connected to a first input end of the first switching circuit 133. Specifically, in the receiving antenna unit 130, the second harmonic signal received and output by the first receiving antenna 1311 may be subjected to high-pass filtering by the first high-pass filter 1312, so as to filter out an unnecessary interference signal in the output signal of the first receiving antenna 1311 (for example, filter out a fundamental wave signal doped in the output signal of the first receiving antenna 1311). Meanwhile, the second harmonic signal is amplified by the first low-noise amplifier 1313, so that the second harmonic signal detection capability of the detection circuit is improved, and noise introduced in the amplification process can be reduced.
Optionally, the receiving antenna unit 130 further comprises a second high pass filter 1322 and a second low noise amplifier 1323. An input terminal of the second high-pass filter 1322 is connected to the second receiving antenna 1321, an output terminal of the second high-pass filter 1322 is connected to an input terminal of the second low-noise amplifier 1323, and an output terminal of the second low-noise amplifier 1323 is connected to a second input terminal of the first switching circuit 133. Specifically, in the receiving antenna unit 130, the third harmonic signal received and output by the second receiving antenna 1321 may be filtered by the second high-pass filter 1322, so as to filter out an unnecessary interference signal in the signal output by the second receiving antenna 1321. And simultaneously, the second low-noise amplifier 1323 is used for amplifying the signal so as to improve the third harmonic signal detection capability of the detection circuit.
It will be appreciated that the receiving antenna unit 130 may be provided with only the first high pass filter 1312 and the first low noise amplifier 1313, or with only the second high pass filter 1322 and the second low noise amplifier 1323, while in alternative embodiments the receiving antenna unit 130 may be provided with the first high pass filter 1312, the first low noise amplifier 1313, the second high pass filter 1322 and the second low noise amplifier 1323 at the same time.
Alternatively, as shown in fig. 2 and 3, the detection signal generation unit 140 includes a mixing circuit 141, a detection signal output circuit 142, and a local oscillation signal output circuit 143. And a receiving antenna unit 130 for receiving the second harmonic signal and the third harmonic signal. The local oscillation signal output circuit 143 is configured to switch and output the first local oscillation signal or the second local oscillation signal to the mixer circuit 141. The mixer circuit 141 is connected to the local oscillation signal output circuit 143 and the receiving antenna unit 130, and is configured to receive the first local oscillation signal and the second harmonic signal and mix them to generate a first mixed signal. The mixing circuit 141 is further configured to receive the second local oscillator signal and the third harmonic signal and mix the second local oscillator signal and the third harmonic signal to generate a second mixed signal. The detection signal output circuit 142 is connected to the mixing circuit 141, and is configured to receive the first mixing signal to generate a first detection signal. The detection signal output circuit 142 is further configured to receive the second mixed signal to generate a second detection signal.
Specifically, in the detection signal generating unit 140, the first local oscillation signal or the second local oscillation signal may be output through switching by the local oscillation signal output circuit 143, that is, in the local oscillation signal output circuit 143, the first local oscillation signal and the second local oscillation signal are not output at the same time. When the receiving antenna unit 130 receives the corresponding second harmonic signal and third harmonic signal at the same time, the mixer circuit 141 may be controlled to mix the first local oscillation signal with the second harmonic signal or mix the second local oscillation signal with the third harmonic signal by switching of the local oscillation signal output circuit 143. When the local oscillation signal output circuit 143 switches to output the first local oscillation signal, the mixer circuit 141 mixes the received first local oscillation signal and the second harmonic signal to obtain a first mixed signal, and the detection signal output circuit 142 may perform corresponding signal processing on the first mixed signal to generate a first detection signal. When the local oscillation signal output circuit 143 switches to output the second local oscillation signal, the mixer circuit 141 mixes the received second local oscillation signal and the third harmonic signal to obtain a second mixed signal, and the detection signal output circuit 142 may perform corresponding signal processing on the second mixed signal to generate a second detection signal.
In this embodiment, the values of the first local oscillation signal and the second local oscillation signal are set reasonably, so that the first mixed signal and the second mixed signal are intermediate frequency signals, which is more convenient for identifying the target object. The first local oscillation signal can be set according to the frequency of the second harmonic signal, and the second local oscillation signal can be set according to the frequency of the third harmonic signal. Specifically, the frequency of the first local oscillation signal may be obtained by subtracting a preset frequency from the frequency of the second harmonic signal, and the second local oscillation signal may be obtained by subtracting the preset frequency from the frequency of the third harmonic signal, so that the mixer circuit 141 may correspondingly mix to obtain the first mixed signal and the second mixed signal as intermediate frequency signals.
Alternatively, as shown in fig. 3, the local oscillation signal output circuit 143 includes a first frequency source 1432, a frequency doubling circuit 1430, and a second switching circuit 1431. A first output of the first frequency source 1432 is configured to output a first local oscillation signal. A second output of the first frequency source 1432 is configured to output a third local oscillation signal. The frequency doubling circuit 1430 is coupled to the second output of the first frequency source 1432 for doubling the third local oscillator signal to generate a second local oscillator signal. The second switching circuit 1431 is connected to the first output terminal of the first frequency source 1432, the frequency doubling circuit 1430 and the mixing circuit 141, and is configured to switch the mixing circuit 141 to receive the first local oscillation signal or the second local oscillation signal.
Specifically, in the local oscillation signal output circuit 143, a first local oscillation signal and a third local oscillation signal are generated by the first frequency source 1432. The first output end of the first frequency source 1432 is configured to output a first local oscillation signal, the second output end of the first frequency source 1432 is configured to output a third local oscillation signal, and the frequency doubling circuit 1430 is configured to perform a frequency doubling operation on the third local oscillation signal, that is, amplify the frequency of the third local oscillation signal by a preset multiple to obtain a second local oscillation signal, where the preset multiple is at least two times. The frequency multiplier 1430 in the embodiment shown in fig. 3 amplifies twice the predetermined multiple. The first local oscillation signal and the third local oscillation signal may be the same or different. The second switching circuit 1431 may be connected to the first frequency source 1432, the frequency doubling circuit 1430, and the mixer circuit 141, respectively, where a first input end of the second switching circuit 1431 is connected to the first frequency source 1432, a second input end of the second switching circuit 1431 is connected to the frequency doubling circuit 1430, and an output end of the second switching circuit 1431 is connected to the mixer circuit 141. The second switching circuit 1431 is configured to switch the first local oscillation signal and the second local oscillation signal, so that the mixer circuit 141 receives only one of the first local oscillation signal and the second local oscillation signal at the same time and mixes the first local oscillation signal and the second local oscillation signal. The second switching circuit 1431 may be a single pole double throw radio frequency switch. According to the embodiment of the invention, the first local oscillation signal and the third local oscillation signal are obtained by adopting the first frequency source 1432, and the second local oscillation signal is obtained by multiplying the frequency of the third local oscillation signal, so that the purpose of saving one frequency source can be achieved by adopting one frequency source to provide corresponding local oscillation signals for the second harmonic signal and the third harmonic signal, and compared with the traditional design scheme that each local oscillation signal is provided by adopting one frequency source, the purpose of saving one frequency source is achieved, and the miniaturized design of a nonlinear node detection circuit is facilitated.
Optionally, the frequency doubling circuit 1430 includes a frequency multiplier 1433, a third high pass filter 1434 and a third low noise amplifier 1435. The input end of the frequency multiplier 1433 is connected to the second output end of the first frequency source 1432, the output end of the frequency multiplier 1433 is connected to the input end of the third high-pass filter 1434, the output end of the third high-pass filter 1434 is connected to the input end of the third low-noise amplifier 1435, and the output end of the third low-noise amplifier 1435 is connected to the second switching circuit 1431. Specifically, generally, since the third harmonic signal has a relatively high frequency, the third local oscillator signal output by the first frequency source 1432 needs to be subjected to frequency multiplication processing by the frequency multiplier 1433 to obtain a second local oscillator signal with a relatively high frequency, and the third high-pass filter 1434 and the third low-noise amplifier 1435 filter and amplify the second local oscillator signal to obtain a pure third-order local oscillator (i.e., the second local oscillator signal), so as to achieve the effect of saving one frequency source. In one embodiment, the second-order local oscillator (i.e., the first local oscillator signal) and the third-order local oscillator (i.e., the second local oscillator signal) may also be generated by using a dedicated frequency source.
Optionally, the detection signal output circuit 142 includes a first low-pass filter 1421, a fourth low-noise amplifier 1422, a crystal filter 1423, and a power detector 1424. The input end of the first low-pass filter 1421 is connected to the output end of the mixer circuit 141, the output end of the first low-pass filter 1421 is connected to the input end of the fourth low-noise amplifier 1422, the output end of the fourth low-noise amplifier 1422 is connected to the input end of the crystal filter 1423, the output end of the crystal filter 1423 is connected to the input end of the power detector 1424, and the output end of the power detector 1424 is used for outputting the first detection signal or the second detection signal.
Specifically, in the detection signal output circuit 142, the first mixing signal and the second mixing signal output by the mixing circuit 141 may be intermediate frequency signals, and the intermediate frequency signals may be processed by an intermediate frequency signal processing circuit composed of a first low-pass filter 1421, a fourth low-noise amplifier 1422, a crystal filter 1423 and a power detector 1424, so as to obtain the first detection signal and the second detection signal correspondingly. When the intermediate frequency signal is a first mixing signal, the intermediate frequency signal filters the second harmonic signal and the second-order local oscillation signal or other high-frequency noise signals through a first low-pass filter 1421, amplifies the signals through a fourth low-noise amplifier 1422, filters the signals except the intermediate frequency signal through a crystal filter 1423, and converts the intermediate frequency signal into a voltage signal through a power detector 1424 to obtain a corresponding first detection signal. When the intermediate frequency signal is the second mixing signal, the intermediate frequency signal filters out high-frequency noise signals such as a third harmonic signal and a third-order local oscillation signal through a first low-pass filter 1421, amplifies the signals through a fourth low-noise amplifier 1422, filters out signals except the intermediate frequency signal through a crystal filter 1423, and converts the intermediate frequency signal into a voltage signal through a power detector 1424 to obtain a corresponding second detection signal. In this embodiment, the sequence of acquisition of the first detection signal and the second detection signal is not required. The detection signal output circuit 142 provided in this embodiment filters by two-stage filters before and after, filters the high-frequency noise signal by the first low-pass filter 1421, filters other noise with a frequency lower than the high-frequency noise by the crystal filter 1423, and can thoroughly filter out noise signals with various frequencies, thereby improving the cleanliness of the intermediate-frequency signal input to the power detector 1424 and further improving the detection precision.
Optionally, the receiving antenna unit 130 further comprises a fifth low noise amplifier 134. An input terminal of the fifth low noise amplifier 134 is connected to an output terminal of the first switching circuit 133, and an output terminal of the fifth low noise amplifier 134 is connected to the detection signal generating unit 140. Specifically, in the receiving antenna unit 130, a fifth low noise amplifier 134 may be further disposed to amplify the received radio frequency signal, and at the same time, noise introduced during the amplification process may be reduced. Specifically, the output terminal of the fifth low noise amplifier 134 may be specifically connected to the mixer circuit 141.
Optionally, the fundamental wave signal generating unit 110 includes a fundamental wave signal conditioning circuit 112 and a second low-pass filter 111. The fundamental wave signal conditioning circuit 112 is configured to generate and condition (e.g., filter process, signal amplifying process) a fundamental wave signal, and an input terminal of the second low-pass filter 111 is connected to an output terminal of the fundamental wave signal conditioning circuit 112, and an output terminal of the second low-pass filter 111 is connected to the transmitting antenna 120. Specifically, in the fundamental wave signal generating unit 110, a conditioned fundamental wave signal is generated by the fundamental wave signal conditioning circuit 112, and the fundamental wave signal is filtered by the second low-pass filter 111 and then transmitted by the transmitting antenna 120. Since the fundamental wave signal conditioning circuit 112 also includes semiconductor devices, the semiconductor devices can generate second harmonic signals and third harmonic signals under the action of the fundamental wave signals and transmit the second harmonic signals and the third harmonic signals to the transmitting antenna 120 correspondingly during operation, so that the second low-pass filter 111 is arranged at the input end of the transmitting antenna 120, and the second low-pass filter 111 is used for filtering the second harmonic signals and the third harmonic signals carried in the output signals of the fundamental wave signal conditioning circuit 112, so as to ensure that the second harmonic signals and the third harmonic signals are not carried in the fundamental wave signals transmitted through the transmitting antenna 120, thereby avoiding the influence of the fundamental wave signal conditioning circuit 112 on the detection result.
In an embodiment, the fundamental wave signal conditioning circuit 112 may include a second frequency source 1123, a digitally controlled attenuator 1122, and a power amplifier 1121, where an output terminal of the second frequency source 1123 is connected to an input terminal of the digitally controlled attenuator 1122, an output terminal of the digitally controlled attenuator 1122 is connected to an input terminal of the power amplifier 1121, and an output terminal of the power amplifier 1121 is connected to an input terminal of the second low-pass filter 111. The second frequency source 1123 may include a phase-locked loop circuit PLL, a VCO voltage-controlled oscillator, a loop filter, etc., the second frequency source 1123 is configured to generate a fundamental wave signal of a corresponding frequency, the digitally controlled attenuator 1122 attenuates the fundamental wave signal generated by the second frequency source 1123, and the power amplifier 1121 amplifies the power of the signal output from the digitally controlled attenuator 1122 and inputs the amplified signal to the second low-pass filter 111.
Optionally, the nonlinear node detection circuit further includes: a main controller 150, a power supply (not shown), a first low-pass filter circuit (not shown), and a second low-pass filter circuit (not shown). The main controller 150 may output control signals to the fundamental wave signal generation unit 110, the reception antenna unit 130, and the detection signal generation unit 140, for example, and the power supply may output power supply to the fundamental wave signal generation unit 110, the reception antenna unit 130, and the detection signal generation unit 140, for example. Wherein, the main controller 150 is connected to the fundamental wave signal generating unit 110 through a first low-pass filter circuit, and the main controller 150 outputs a control signal to the fundamental wave signal generating unit 110 through the first low-pass filter circuit. The power supply is connected to the fundamental wave signal generating unit 110 through a second low-pass filter circuit, and the power supply outputs a power supply to the fundamental wave signal generating unit 110 through the second low-pass filter circuit.
Specifically, the main controller 150 may be implemented by a microprocessor such as MCU, DSP, FPGA or a main control chip. In the detection circuit, a control signal can be generated by the main controller 150 and output to the fundamental wave signal generation unit 110 for controlling the fundamental wave signal generation process of the fundamental wave signal generation unit 110. The main controller 150 may also be configured to output a control signal to the detection signal generating unit 140 to control the operation of the detection signal generating unit 140, so that the detection signal generating unit 140 may generate the corresponding first detection signal or the second detection signal according to the received second harmonic signal or third harmonic signal. The receiving antenna unit 130 may also operate according to the received control signal output from the main controller 150 to perform corresponding second harmonic signal or third harmonic signal reception. Thus, since the fundamental wave signal generating unit 110 in the transmitting path and the receiving antenna unit 130 and the detecting signal generating unit 140 in the receiving path may all use the same main controller 150 for operation control, a signal path (including signal lines and various functional circuits) through which the control signal output from the main controller 150 to the fundamental wave signal generating unit 110 is defined as a first control signal path, a signal path through which the control signal output from the main controller 150 to the receiving antenna unit 130 is defined as a second control signal path, and a signal path through which the control signal output from the main controller 150 to the detecting signal generating unit 140 is defined as a third control signal path. Therefore, the second harmonic signal or the third harmonic signal generated by the fundamental wave signal generating unit 110 under the fundamental wave signal may be coupled to the main controller 150 through the first control signal path, and then reach the receiving antenna unit 130 and the detecting signal generating unit 140 through the second control signal path and the third control signal path by the main controller 150, so as to affect the detection result. Therefore, in order to overcome the above-mentioned problems, the first low-pass filter 1421 is disposed on the first control signal path in the embodiments of the present invention to filter the second harmonic signal and the third harmonic signal generated by the fundamental wave signal generating unit 110, so as to ensure that no second harmonic signal and no third harmonic signal enter the receiving path (such as the receiving antenna unit 130 and the detecting signal generating unit 140) from the source through the main controller 150.
Also, if the detection circuit internal circuits such as the fundamental wave signal generation unit 110, the reception antenna unit 130, and the detection signal generation unit 140 are simultaneously supplied with power by the same power source, the power path through which the power source output to the fundamental wave signal generation unit 110 passes (including the power source line and various functional circuits) is defined herein as a first power source path, the power path through which the power source output to the reception antenna unit 130 passes is defined as a second power source path, and the power path through which the power source output to the detection signal generation unit 140 passes is defined as a third power source path. In the power supply process of the power supply to the fundamental wave signal generating unit 110, the second harmonic signal or the third harmonic signal generated by the fundamental wave signal generating unit 110 under the fundamental wave signal may be coupled to the power supply through the first power supply path, and then reach the receiving antenna unit 130 and the detection signal generating unit 140 through the second power supply path and the third power supply path respectively, so as to affect the detection result. In the embodiment of the present invention, by providing the second low-pass filter circuit on the first power supply path, the power supply output to the fundamental wave signal generating unit 110 needs to pass through the second low-pass filter circuit, and the second low-pass filter circuit can also filter the second harmonic signal and the third harmonic signal generated by the fundamental wave signal generating unit 110 in the transmitting path, so as to ensure that the second harmonic signal and the third harmonic signal cannot enter the receiving path (such as the receiving antenna unit 130 and the detecting signal generating unit 140) through the power supply from the source.
The above procedure can be understood that a corresponding low-pass filter circuit is added to the corresponding first power supply path and first control signal path of the fundamental wave signal generation unit 110 to prevent the second and third harmonic signals generated by the fundamental wave signal generation unit 110 from entering the detection signal generation unit 140 and the receiving antenna unit 130.
In an embodiment, the switching units (e.g., the first switching circuit 133 and the second switching circuit 1431) may be controlled and switched by the main controller 150, so that the receiving antenna unit 130 and the detecting signal generating unit 140 may respectively receive and detect the second harmonic signal and the third harmonic signal according to the control of the main controller 150.
In an embodiment, corresponding low-pass filter circuits may also be added to the second and third power supply paths and the second and third control signal paths of the detection signal generating unit 140 and the receiving antenna unit 130, so as to avoid that corresponding second harmonic signals and third harmonic signals enter the detection signal generating unit 140 and the receiving antenna unit 130 to make the generated first and second detection signals have larger errors.
The first low-pass filter circuit and the second low-pass filter circuit may be LC low-pass filters formed by inductors and capacitors, at least one of which is used in one embodiment, as in the embodiment shown in fig. 4, LC low-pass filters (204, 205) formed by 3 inductors (201, 202, 203) and 2 capacitors are used in the LC low-pass filters. A first terminal of the inductor 201 may be used as an input terminal of the LC low-pass filter circuit, a second terminal of the inductor 201 is connected to a first terminal of the capacitor 204 and a first terminal of the inductor 202, a second terminal of the inductor 202 is connected to a first terminal of the capacitor 205 and a first terminal of the inductor 203, and a second terminal of the inductor 203 is used as an output terminal of the low-pass filter. The second terminals of the capacitor 204 and the capacitor 205 are grounded.
The embodiment of the invention also provides a nonlinear node detection device which comprises the nonlinear node detection circuit. Namely, detection of the semiconductor device or the metal rusting node is achieved by the above detection circuit.
It is to be understood that the above examples only represent preferred embodiments of the present invention, which are described in more detail and detail, but are not to be construed as limiting the scope of the invention. It should be noted that it is possible for a person skilled in the art to freely combine the technical features described above without departing from the spirit of the invention, and to make several variants and modifications, all of which are within the scope of protection of the invention. Therefore, all changes and modifications that come within the meaning and range of equivalency of the claims are to be embraced within their scope.
Claims (11)
1. A nonlinear node detection circuit, comprising: a fundamental wave signal generating unit, a transmitting antenna, a detection signal generating unit and a receiving antenna unit;
The transmitting antenna is connected with the fundamental wave signal generating unit and is used for receiving the fundamental wave signal generated by the fundamental wave signal generating unit and transmitting the fundamental wave signal;
the receiving antenna unit is used for receiving the second harmonic signal and/or the third harmonic signal corresponding to the fundamental wave signal;
The detection signal generation unit is connected with the receiving antenna unit and is used for generating a first detection signal corresponding to the second harmonic signal when the receiving antenna unit receives the second harmonic signal and generating a second detection signal corresponding to the third harmonic signal when the receiving antenna unit receives the third harmonic signal;
The nonlinear node detection circuit further comprises a main controller and a first low-pass filter circuit, wherein the main controller is connected with the fundamental wave signal generation unit through the first low-pass filter circuit, and the main controller outputs a control signal to the fundamental wave signal generation unit through the first low-pass filter circuit; and/or the nonlinear node detection circuit further comprises a power supply and a second low-pass filter circuit, wherein the power supply is connected with the fundamental wave signal generation unit through the second low-pass filter circuit, and the power supply outputs a power supply to the fundamental wave signal generation unit through the second low-pass filter circuit.
2. The nonlinear node detection circuit in accordance with claim 1, wherein the receive antenna unit comprises a first receive antenna, a second receive antenna, and a first switching circuit;
the first receiving antenna is used for receiving the second harmonic signal and outputting the second harmonic signal, and the second receiving antenna is used for receiving the third harmonic signal and outputting the third harmonic signal;
The first switching circuit is connected with the first receiving antenna, the second receiving antenna and the detection signal generating unit and is used for switching the detection signal generating unit to receive the second harmonic signal or the third harmonic signal.
3. The nonlinear node detection circuit in accordance with claim 2, wherein the receive antenna unit further comprises a first high pass filter and a first low noise amplifier; the input end of the first high-pass filter is connected with the first receiving antenna, the output end of the first high-pass filter is connected with the input end of the first low-noise amplifier, and the output end of the first low-noise amplifier is connected with the first input end of the first switching circuit;
And/or the receiving antenna unit further comprises a second high pass filter and a second low noise amplifier; the input end of the second high-pass filter is connected with the second receiving antenna, the output end of the second high-pass filter is connected with the input end of the second low-noise amplifier, and the output end of the second low-noise amplifier is connected with the second input end of the first switching circuit.
4. The nonlinear node detection circuit according to claim 1, wherein the detection signal generation unit includes a mixing circuit, a detection signal output circuit, and a local oscillation signal output circuit;
The receiving antenna unit is used for receiving the second harmonic signal and the third harmonic signal;
The local oscillation signal output circuit is used for switching and outputting a first local oscillation signal or a second local oscillation signal to the mixing circuit;
The mixing circuit is connected with the local oscillation signal output circuit and the receiving antenna unit, and is used for receiving the first local oscillation signal and the second harmonic signal and mixing to generate a first mixing signal, and is used for receiving the second local oscillation signal and the third harmonic signal and mixing to generate a second mixing signal;
The detection signal output circuit is connected with the mixing circuit and is used for receiving the first mixing signal to generate the first detection signal and receiving the second mixing signal to generate the second detection signal.
5. The nonlinear node detection circuit according to claim 4, wherein the local oscillator signal output circuit comprises a first frequency source, a frequency doubling circuit, and a second switching circuit;
the first output end of the first frequency source is used for outputting the first local oscillation signal;
the second output end of the first frequency source is used for outputting a third local oscillation signal;
the frequency doubling circuit is connected with the second output end of the first frequency source and is used for doubling the frequency of the third local oscillation signal to generate the second local oscillation signal;
The second switching circuit is connected with the first output end of the first frequency source, the frequency doubling circuit and the mixing circuit and is used for switching the mixing circuit to receive the first local oscillation signal or the second local oscillation signal.
6. The nonlinear node detection circuit in accordance with claim 5, wherein the frequency multiplier circuit comprises a frequency multiplier, a third high pass filter, and a third low noise amplifier;
the input end of the frequency multiplier is connected with the second output end of the first frequency source, the output end of the frequency multiplier is connected with the input end of the third high-pass filter, the output end of the third high-pass filter is connected with the input end of the third low-noise amplifier, and the output end of the third low-noise amplifier is connected with the second switching circuit.
7. The nonlinear node detection circuit in accordance with claim 4, wherein the detection signal output circuit comprises a first low pass filter, a fourth low noise amplifier, a crystal filter, and a power detector;
The input end of the first low-pass filter is connected with the output end of the mixing circuit, the output end of the first low-pass filter is connected with the input end of the fourth low-noise amplifier, the output end of the fourth low-noise amplifier is connected with the input end of the crystal filter, the output end of the crystal filter is connected with the input end of the power detector, and the output end of the power detector is used for outputting the first detection signal or the second detection signal.
8. The nonlinear node detection circuit in accordance with claim 2, wherein the receive antenna unit further comprises a fifth low noise amplifier;
The input end of the fifth low noise amplifier is connected with the output end of the first switching circuit, and the output end of the fifth low noise amplifier is connected with the detection signal generation unit.
9. The nonlinear node detection circuit in accordance with claim 1, wherein the fundamental wave signal generating unit comprises a fundamental wave signal conditioning circuit and a second low pass filter;
The fundamental wave signal conditioning circuit is used for generating and conditioning the fundamental wave signals, the input end of the second low-pass filter is connected with the output end of the fundamental wave signal conditioning circuit, and the output end of the second low-pass filter is connected with the transmitting antenna.
10. The nonlinear node detection circuit according to any one of claims 1-9, wherein when the nonlinear node detection circuit further comprises a main controller and a first low-pass filter circuit, the nonlinear node detection circuit further comprises a third low-pass filter and a fourth low-pass filter;
The main controller is connected with the receiving antenna unit through the third low-pass filter circuit, and outputs a control signal to the receiving antenna unit through the third low-pass filter circuit; the main controller is connected with the detection signal generation unit through the fourth low-pass filter circuit, and outputs a control signal to the detection signal generation unit through the fourth low-pass filter circuit;
and/or, when the nonlinear node detection circuit further comprises a power supply and a second low-pass filter circuit, the nonlinear node detection circuit further comprises a fifth low-pass filter and a sixth low-pass filter;
the power supply is connected with the receiving antenna unit through the fifth low-pass filter circuit, and the power supply outputs a power supply to the receiving antenna unit through the fifth low-pass filter circuit; the power supply is connected with the detection signal generation unit through the sixth low-pass filter circuit, and the power supply outputs a power supply to the detection signal generation unit through the sixth low-pass filter circuit.
11. A nonlinear node detecting device comprising a nonlinear node detecting circuit according to any one of claims 1 to 10.
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| CN202410428776.7A CN118295034A (en) | 2024-02-23 | 2024-02-23 | Nonlinear node detection circuit and detection device |
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| US6057765A (en) * | 1998-10-07 | 2000-05-02 | Research Electronics International | Non-linear junction detector |
| US6163259A (en) * | 1999-06-04 | 2000-12-19 | Research Electronics International | Pulse transmitting non-linear junction detector |
| GB2381078B (en) * | 1999-06-04 | 2003-10-01 | Res Electronics Internat | Pulse transmitting non-linear junction detector |
| CN203250023U (en) * | 2013-03-15 | 2013-10-23 | 程晓辉 | Non-linear junction detector based on S-wave band |
| CN106533486A (en) * | 2015-09-14 | 2017-03-22 | 公安部第研究所 | 2.4 GHz handheld nonlinear node detector |
| CN205049754U (en) * | 2015-09-24 | 2016-02-24 | 长春市泽安科技有限公司 | Compound non -linear node detector of metal |
| CN108196236B (en) * | 2017-12-13 | 2020-11-06 | 上海微波技术研究所（中国电子科技集团公司第五十研究所） | Learning-based fuzzy logic decision and interference automatic elimination method and harmonic radar |
| CN110045429A (en) * | 2019-05-28 | 2019-07-23 | 长春市泽安科技有限公司 | Portable 2.4G nonlinear node detection system |
| CN111142166A (en) * | 2019-12-27 | 2020-05-12 | 上海微波技术研究所（中国电子科技集团公司第五十研究所） | Portable electronic device detection system |
| CN114324593B (en) * | 2021-12-31 | 2024-06-18 | 中广核检测技术有限公司 | Nonlinear ultrasonic routine ultrasonic comprehensive detection device and method |
| CN117572352A (en) * | 2023-09-21 | 2024-02-20 | 军工保密资格审查认证中心 | Nonlinear junction detector based on multidimensional polarization characteristic identification and detection method |
| CN117538941A (en) * | 2023-11-21 | 2024-02-09 | 上海华智兴远工业设备有限公司 | Portable nonlinear node detection equipment and detection flow |
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