CN117870852B

CN117870852B - Detector and electronic hearing circuit thereof

Info

Publication number: CN117870852B
Application number: CN202410275565.4A
Authority: CN
Inventors: 匡载栋; 罗育佳; 刘兴伟
Original assignee: Shenzhen Anweipu Technology Co ltd
Current assignee: Shenzhen Anweipu Technology Co ltd
Priority date: 2024-03-12
Filing date: 2024-03-12
Publication date: 2024-06-25
Anticipated expiration: 2044-03-12
Also published as: CN117870852A

Abstract

The invention relates to a detector and an electronic hearing circuit thereof, wherein the electronic hearing circuit comprises a transmitting path and a receiving path, the transmitting path is used for transmitting a detection signal to a target detection object, and the receiving path comprises: the receiving antenna is used for receiving electromagnetic wave signals of a preset frequency band, converting the electromagnetic wave signals of the preset frequency band into induction electric signals and outputting the induction electric signals; the extraction module is electrically connected with the receiving antenna and is used for extracting an electric signal containing a target frequency band from the induction electric signal; the signal processing module is electrically connected with the extraction module and is used for performing signal processing on the electric signal output by the extraction module so as to obtain an electric signal of a target frequency band. Through the technical scheme, the electronic listening circuit provided by the invention can process noise signals in the electronic listening circuit to obtain the electric signal representing the target frequency band even if the electronic listening circuit is interfered during working, so that the investigation efficiency and the investigation accuracy of investigation personnel are improved.

Description

Detector and electronic hearing circuit thereof

Technical Field

The invention relates to the field of electronic hearing, in particular to a detector and an electronic hearing circuit thereof.

Background

At present, a detector with an electronic listening function is generally used for detecting an object, such as an explosive with a timing explosion function, and a mechanical or electronic timing detonating device is required to be adopted in the explosive with the timing explosion function, and the detector with the electronic listening function can monitor the mechanical or electronic timing detonating device and emit a corresponding sound signal, so that a detector can detect the explosive according to the sound signal. However, with the popularization and application of various types of electronic devices, the detector is easily interfered by nearby electronic devices during working, so that more noise exists in the sound signals sent by the detector, and therefore, the detection personnel are difficult to lock explosives according to the sound signals sent by the detector, and the detection efficiency and the detection precision of the detection personnel are further affected.

Disclosure of Invention

The invention aims to solve the technical problem that the noise of the detection result is large in the prior art, and provides a detector and an electronic listening circuit thereof.

The technical scheme adopted by the embodiment of the invention for solving the technical problems is as follows: an electronic listening circuit is constructed, comprising a transmit path for transmitting a probe signal to a target probe and a receive path comprising:

the receiving antenna is used for receiving electromagnetic wave signals of a preset frequency band, converting the electromagnetic wave signals of the preset frequency band into induction electric signals and outputting the induction electric signals;

the extraction module is electrically connected with the receiving antenna and is used for extracting an electric signal containing a target frequency band from the induction electric signal;

and the signal processing module is electrically connected with the extraction module and is used for performing signal processing on the electric signal output by the extraction module so as to obtain the electric signal of the target frequency band.

Preferably, the extraction module is further electrically connected with the transmission path to access the electrical signal in the transmission path;

the extraction module is used for extracting the electric signal containing the target frequency band from the induction electric signal according to the electric signal in the transmission path.

Preferably, the extraction module comprises:

the first amplifier is electrically connected with the receiving antenna and is used for amplifying the induction electric signal output by the receiving antenna;

The first input end of the mixer is electrically connected with the first amplifier, the second input end of the mixer is electrically connected with the transmitting path, and the output end of the mixer is electrically connected with the signal processing module; the frequency mixer is used for carrying out frequency mixing processing on the induction signal amplified by the first amplifier and the electric signal in the transmitting path so as to remove frequency components which are the same as the electric signal frequency band in the transmitting path in the induction electric signal and obtain the electric signal containing the target frequency band.

Preferably, the transmitting path comprises a signal generating module, a first amplifying module and a transmitting antenna which are electrically connected in sequence;

the second input end of the mixer is electrically connected with the output end of the first amplifying module.

Preferably, the signal processing module comprises a low noise amplifier and a filtering module, wherein the input end of the low noise amplifier is electrically connected with the output end of the extraction module, and the output end of the low noise amplifier is electrically connected with the filtering module.

Preferably, the filtering module includes a first filter and a second filter, and the signal processing module further includes a second amplifier;

The input end of the first filter is electrically connected with the low noise amplifier, the input end of the second amplifier is electrically connected with the output end of the first filter, and the output end of the second amplifier is electrically connected with the input end of the second filter.

Preferably, the receiving path further includes:

And the amplitude adjusting module is electrically connected with the signal processing module and is used for adjusting the amplitude of the electric signal of the target frequency band.

The embodiment of the invention also constructs a detector which comprises the electronic hearing circuit.

Preferably, the detector further comprises a probe, a connecting rod and a handle which are sequentially connected, wherein a power load is arranged in the probe, and the power load comprises the electronic hearing circuit and a modulation module; a demodulation module and a direct current power supply are arranged in the handle; a transmission line is arranged in the connecting rod; the transmission line is a power line or an audio line;

The modulation module is electrically connected with the electronic hearing circuit; the first end of the transmission line is respectively connected with the signal output end of the modulation module and the power supply end of the power load; the second end of the transmission line is respectively connected with the demodulation module and the direct current power supply;

the modulation module is used for modulating the electric signal output by the electronic listening circuit, outputting the modulated electric signal to the demodulation module through the transmission line, and outputting the modulated electric signal after demodulation processing through the demodulation module; the direct-current power supply is used for outputting a direct-current voltage signal to a power supply end of the power load through the transmission line so as to supply power for the power load.

Preferably, at least one of a first isolation unit and a third isolation unit is arranged in the detector, wherein a first end of the first isolation unit is electrically connected with a signal output end of the modulation module, and a second end of the first isolation unit is electrically connected with a first end of the transmission line and a power supply end of the power load respectively; the first end of the third isolation unit is electrically connected with the demodulation module, and the second end of the third isolation unit is electrically connected with the second end of the transmission line and the direct current power supply respectively; the first isolation unit and the third isolation unit are used for isolating direct current signals.

Preferably, at least one of a second isolation unit and a fourth isolation unit is disposed in the detector, wherein the second isolation unit is electrically connected between a power source end of the power load and a first end of the transmission line, and the fourth isolation unit is electrically connected between a second end of the transmission line and the direct current power source; the second isolation unit and the fourth isolation unit are used for isolating alternating current signals.

In the technical scheme provided by the embodiment of the invention, the signal processing module is arranged in the receiving channel of the electronic hearing circuit, so that the signal processing can be carried out on the electric signal containing the target frequency band extracted by the extracting module, and even if the electronic hearing circuit is interfered by nearby electronic equipment during working, noise signals in the electronic hearing circuit can be processed, thereby being beneficial to improving the detection efficiency and the detection precision of detection personnel.

Drawings

In order to more clearly illustrate the embodiments of the present invention, the drawings that are required for the description of the embodiments will be briefly described below, it being apparent that the drawings in the following description are only some embodiments of the present invention and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art. In the accompanying drawings:

Fig. 1 is a schematic circuit diagram of a first embodiment of an electronic listening circuit according to the present invention.

Fig. 2 is a circuit block diagram of a second embodiment of an electronic listening circuit according to the present invention.

Fig. 3 is a circuit block diagram of a third embodiment of the electronic listening circuit of the present invention.

Fig. 4 is a schematic circuit block diagram of a first embodiment of the detector of the present invention.

Fig. 5 is a schematic circuit diagram of a second embodiment of the detector of the present invention.

Description of the reference numerals:

100: an electronic listening circuit; 1001: a transmit path; 1002: a receive path;

10021: a receiving antenna; 10022: an extraction module; 10023: a signal processing module;

ANT2: an antenna; a3: a first amplifier; m1: a mixer; 10011: a signal generation module; 10012: a first amplifying module; 10013: a transmitting antenna; u1: a phase locked loop; VCO: a voltage controlled oscillator; f1: a frequency multiplier; a1: an amplifier; a2: an amplifier; ANT1: an antenna;

100231: a low noise amplifier; 100232: a filtering module; z1: a first filter; z2: a second filter; 100233: a second amplifier; a4: an amplifier;

10024: an amplitude adjusting module; u2: a digital potentiometer;

10: a probe; 20: a connecting rod; 30: a handle; 107: a power load; 101: a modulation module; 104: a demodulation module; DC: a direct current power supply; 103: a transmission line; 102: a first isolation unit; 108: a second isolation unit; 106: a third isolation unit; 105: a fourth isolation unit; and C3: a capacitor; l2: an inductance; c2: a capacitor; l1: an inductance; u11: an FM modulation chip; u12: FM demodulation chip.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed. The connection may be direct connection, indirect connection via an intermediate medium, communication between two elements or interaction relationship between two elements, or direct connection between two circuit modules or connection via other modules. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

Fig. 1 is a circuit block diagram of an embodiment of an electronic listening circuit according to the present invention, and the electronic listening circuit 100 of the embodiment includes a transmit path 1001 and a receive path 1002. Wherein the transmission path 1001 is used for transmitting a detection signal to a target detection object. The receiving path 1002 includes a receiving antenna 10021, an extracting module 10022 and a signal processing module 10023 that are electrically connected in sequence, where the receiving antenna 10021 is configured to receive an electromagnetic wave signal in a preset frequency band, and convert the electromagnetic wave signal in the preset frequency band into an induced electric signal and output the induced electric signal. The extracting module 10022 is configured to extract an electrical signal including a target frequency band from the induction electrical signal. The signal processing module 10023 is configured to perform signal processing, including but not limited to filtering, on the electrical signal output by the extracting module 10022 to obtain an electrical signal of the target frequency band.

In operation, the electronic listening circuit 100 of this embodiment first transmits a detection signal at a specific frequency (e.g., frequency f 1) through the transmission path 1001 toward a target detector (e.g., a target detector suspected of having an explosive with a timed explosion function).

If the target probe has an explosive with a timing explosion function (i.e. there is a mechanical or electronic timing detonation device), and no matter the mechanical or electronic timing detonation device will have a corresponding clock frequency f2, according to the doppler principle, the mechanical or electronic timing detonation device will correspond to an electromagnetic wave signal with a radiation frequency f1+f2 after receiving the detection signal (f1+f2 is one example of a preset frequency band). Thus, the receiving antenna 10021 can receive the electromagnetic wave signal with the frequency f1+f2, then convert the electromagnetic wave signal into an electric signal to obtain an electric signal with the frequency f1+f2 (i.e. an induced electric signal), and then convert the induced electric signal into an audio signal through corresponding signal processing, so that a inspector can listen to determine whether explosives exist, thereby realizing the electronic listening function. However, in practical applications, it is found that the induction electric signal includes, in addition to the electric signal with the frequency f1+f2, a noise signal with a frequency other than f2 generated by interference of other noises (such as electronic devices) nearby, and the noise signal is also received by the receiving antenna 10021 and coupled to the finally generated audio signal along with the signal processing process, so as to affect the judgment of the inspector.

In this embodiment, the extracting module 10022 may extract an electrical signal including a target frequency band (i.e. a frequency band related to the target probe, for example, including f2 frequency) from the induced electrical signal, and the electrical signal extracted by the extracting module 10022 may also include a noise signal. In the embodiment of the invention, the signal processing module 10023 is used to perform signal processing, such as filtering processing, on the electrical signal extracted by the extracting module 10022, so as to filter out noise signals except the target frequency band, thereby obtaining the electrical signal of the target frequency band (for example, the frequency is f 2). It should be noted that, the above-mentioned target frequency band is, for example, in the frequency range of the audio signal, that is, the electric signal of the target frequency band may be used as the audio signal, so that the electronic listening function may be implemented by transmitting the electric signal of the target frequency band obtained by the electronic listening circuit to the earphone or the loudspeaker for playing.

In contrast, if the target probe does not have an explosive (i.e., no mechanical or electronic timing detonators are present) in the target probe. In this way, the receiving antenna 10021 receives the electromagnetic wave signal with the frequency f1 emitted by itself and then converts it into an induced electrical signal, where the induced electrical signal may also include a noise signal generated by interference of nearby electronic devices, in addition to the electrical signal with the frequency f 1. While the frequency f1 is not in the target frequency band, the electrical signal extracted by the extracting module 10022 may only include a noise signal. Finally, the signal processing module 10023 performs signal processing, such as filtering, on the extracted electrical signal to remove the noise signal, so that the electronic listening circuit does not output the electrical signal in the target frequency band (frequency f 2). Accordingly, the detector will not have an audio signal for playing, so that a inspector can determine that there is no explosive in the target detector with the timing explosion function.

In the technical solution of this embodiment, since the signal processing module 10023 is disposed in the receiving channel 1002 of the electronic listening circuit, the signal processing module 10023 can perform signal processing on the electrical signal including the target frequency band extracted by the extracting module 10022, so as to remove the noise signal not in the target frequency band in the output signal of the extracting module 10022, so that even if the detector is interfered by the nearby electronic device during working, the electronic listening circuit provided by the embodiment of the invention can also process the noise signal therein, thereby improving the detection efficiency and accuracy of the detection personnel.

Further, as shown in fig. 1, the extraction module 10022 is further electrically connected to the transmission path 1001 to access the electrical signal in the transmission path 1001, and the extraction module 10022 is configured to extract the electrical signal including the target frequency band from the induction electrical signal according to the electrical signal in the transmission path 1001. In this embodiment, when sound detection is performed, the transmission path 1001 converts an electric signal of a specific frequency (for example, frequency f 1) generated into an electromagnetic wave signal (detection signal) and transmits the electromagnetic wave signal. If the target detection object is provided with a mechanical or electronic timing detonating device, the mechanical or electronic timing detonating device can correspond to an electromagnetic wave signal with the radiation frequency of f1+f2 (preset frequency band) after receiving the detection signal according to the Doppler principle. Thus, the receiving antenna 10021 can receive the electromagnetic wave signal and then convert the electromagnetic wave signal into an induced electrical signal, where the induced electrical signal at least includes an electrical signal with a frequency of f1+f2 and an electrical signal with a frequency of f1.

When the extracting module 10022 extracts a signal, since an electrical signal is accessed from the transmitting path 1001, the accessed electrical signal may be an electrical signal related to a frequency band (such as f 1) where the probe signal is located, for example, the related electrical signal may be an electrical signal in the f1 frequency band, or may be an electrical signal that needs to be processed to be in the f1 frequency band. The extraction module 10022 may use the related electrical signal to filter out the f1 frequency band component of the induced electrical signal, that is, filter out the f1 frequency of the electrical signal with the frequency f1+f2, and filter out the electrical signal with the frequency f1 to obtain the signal with the f2 frequency band component only. In addition, compared with the mode of acquiring the electric signal in the transmission path 1001 by sampling and software processing, the mode of directly accessing the electric signal from the transmission path 1001 has the advantages of simple circuit structure, easier realization, lower requirement on hardware configuration and lower cost.

Fig. 2 is a circuit block diagram of a second embodiment of the electronic listening circuit according to the present invention, where the electronic listening circuit 100 of the present invention includes a transmitting path 1001 and a receiving path 1002, and the transmitting path 1001 is used for transmitting a detection signal to a target detection object. The reception path 1002 includes a reception antenna 10021, an extraction module 10022, and a signal processing module 10023, which are electrically connected in this order, and the reception antenna 10021 includes an antenna ANT2.

Further, the extracting module 10022 uses, for example, mixing or other manners to extract the electric signal including the target frequency band from the induction electric signal by using the electric signal in the transmission path 1001. As shown in fig. 2, the extraction module 10022 includes a first amplifier A3 and a mixer M1, wherein an input end of the first amplifier A3 is electrically connected to the receiving antenna 10021, and is configured to amplify an induced electric signal output by the receiving antenna 10021. A first input of the mixer M1 is electrically connected to the output of the first amplifier A3, a second input of the mixer M1 is electrically connected to the transmit path 1001, and an output of the mixer M1 is electrically connected to the signal processing module 10023. The mixer M1 is configured to mix the induced electrical signal amplified by the first amplifier A3 with the electrical signal in the transmission path 1001, so as to remove the frequency component of the induced electrical signal, which is the same as the frequency band of the electrical signal in the transmission path 1001, and obtain the electrical signal including the target frequency band. In this embodiment, the mixer M1 may be a subtracting mixer, which may subtract the induced electrical signal (the electrical signal with the frequency of f1+f2 and the electrical signal with the frequency of f 1) input at the first input end from the electrical signal in the transmission path 1001 input at the second input end to obtain the electrical signal with the frequency of f2, that is, the electrical signal of the target frequency band.

Further, as shown in fig. 2, the transmission path 1001 includes a signal generating module 10011, a first amplifying module 10012, and a transmitting antenna 10013 electrically connected in this order. The signal generating module 10011 specifically includes, for example, a phase-locked loop U1, a voltage-controlled oscillator VCO, and a frequency multiplier F1 electrically connected in sequence. The first amplifying module 10012 is, for example, a two-stage amplifying module, and includes an amplifier A1 and an amplifier A2 electrically connected. The transmitting antenna 10013 includes an antenna ANT1. When the transmission path 1001 needs to transmit a signal, the phase-locked loop U1 outputs a corresponding control voltage to control the VCO to output an output signal with a preset frequency to the frequency multiplier F1, where the output signal is subjected to frequency multiplication by the frequency multiplier F1 (e.g., A2-fold frequency multiplier), and then amplified by the amplifier A1 and the amplifier A2 in sequence, and then outputs an electrical signal with a frequency of, for example, F1 to the antenna ANT1, so as to drive the antenna ANT1 to transmit an electromagnetic wave signal with a frequency of, for example, F1. Also, in this embodiment, the extraction module 10022 may be electrically connected to a device interposed between the signal generation module 10011 and the transmitting antenna 10013. Specifically, the second input of the mixer M1 is electrically connected to the output of the first amplifying module 10012, for example, to the output of the amplifier A2, so as to access the radio frequency signal output by the first amplifying module 10012 to the transmitting antenna 10013. In the embodiment of the invention, the radio frequency signal for the antenna 10013 to transmit is accessed from the transmitting path 1001 to realize the filtering of the f1 frequency band by the mixer M1, and compared with a software implementation scheme of firstly sampling the radio frequency signal and then filtering the f1 frequency band by an algorithm, the embodiment of the invention does not need higher hardware configuration requirements required by sampling the high-energy radio frequency signal, and has lower circuit cost.

It should be noted that, in other embodiments, the extracting module 10022 may be further electrically connected to the output end of the signal generating module 10011. For example: in the receiving path 1002, the extracting module 10022 may further include a second amplifying module configured identically to the first amplifying module 10012, and the second input terminal of the mixer M1 is electrically connected to the output terminal of the signal generating module 10011 in the transmitting path through the second amplifying module, so that the second input terminal of the mixer M1 may finally also receive the electric signal with the frequency f 1.

Further, as shown in fig. 2, the signal processing module 10023 includes a low noise amplifier 100231 and a filtering module 100232, where an input end of the low noise amplifier 100231 is electrically connected to an output end of the extracting module 10022, and an output end of the low noise amplifier 100231 is electrically connected to the filtering module 100232. Furthermore, the low noise amplifier 100231 in this embodiment is, for example, a low noise N-type triode T1, the base of the triode T1 is connected to the output terminal of the mixer M1, the collector of the triode T1 is connected to the power supply voltage Vcc, and the emitter of the triode T1 is grounded. Of course, in other embodiments, the low noise amplifier 100231 may also be any other type of low noise amplifier such as an N-type MOS transistor, which is not limited in the present invention. In this embodiment, when the signal processing module 10023 performs signal processing on the electrical signal output by the extracting module 10022, since the low noise amplifier 100231 performs low noise amplification on the electrical signal first, new noise can be avoided from being introduced during the amplification process. In addition, the filtering module 100232 can filter out the noise signal with the frequency not being f2 by filtering the amplified electric signal, so that the noise in the electric signal of the target frequency band can be reduced.

Further, as shown in fig. 2, the filtering module 100232 includes a first filter Z1 and a second filter Z2, and the signal processing module 10023 further includes a second amplifier 100233, and the second amplifier 100233 includes an amplifier A4, where an input terminal of the first filter Z1 is electrically connected to the low noise amplifier 100231, an input terminal of the second amplifier 100233 is electrically connected to an output terminal of the first filter Z1, and an output terminal of the second amplifier 100233 is electrically connected to an input terminal of the second filter Z2. In this embodiment, the filtering module 100232 is a dual filtering module, that is, the electrical signal is filtered by the first filter Z1, amplified by the second amplifier 100233, and filtered by the second filter Z2, so that the noise signal with the frequency not f2 can be filtered out to the maximum extent, and the noise in the electrical signal in the target frequency band can be reduced.

In some embodiments, the first filter Z1 may be a band-pass filter, and may also include a low-pass filter and a high-pass filter connected. Likewise, the second filter Z2 may be a band-pass filter, and may also include a low-pass filter and a high-pass filter connected.

Fig. 3 is a circuit block diagram of a third embodiment of an electronic listening circuit according to the present invention, which differs from the embodiment shown in fig. 2 only in that the receiving path 1002 further includes an amplitude adjustment module 10024, and the amplitude adjustment module 10024 is electrically connected to the signal processing module 10023 and is used for adjusting the amplitude of the electric signal of the target frequency band. Moreover, the amplitude adjustment module 10024 may include, for example, a digital potentiometer U2, where the digital potentiometer U2 may perform amplitude adjustment on the filtered electrical signal output by the second filter Z2, thereby adjusting the magnitude of the sound signal finally generated by the detector. Finally, the same parts of the electronic listening circuit of the embodiment as those of the embodiment shown in fig. 2 are described above, and will not be described again.

Fig. 4 is a schematic circuit diagram of a first embodiment of the detector according to the present invention, where the detector includes a probe 10, a connecting rod 20, and a handle 30 connected in sequence, and a power load 107 is disposed in the probe 10, where the power load 107 includes an electronic listening circuit 100 and a modulation module 101, or where the power load 107 may further include other functional modules in the probe 10 that need to supply power for operation. It should be noted that, although the electronic listening circuit 100 and the modulation module 101 also belong to one kind of the power load 107, the electronic listening circuit 100 and the modulation module 101 are distinguished from the power load 107 in fig. 4 and the present embodiment for clarity of description. A demodulation module 104 and a direct current power supply DC are provided in the handle 30. A transmission line 103 is disposed in the connecting rod 20, and the transmission line 103 is a power line or an audio line.

The modulation module 101 is electrically connected to the electronic listening circuit 100, a first end of the transmission line 103 is respectively connected to a signal output end of the modulation module 101 and a power supply end of the power load 107 (including a power supply end of the electronic listening circuit 100, a power supply end of the modulation module 101 or a power supply end of other power loads), and a second end of the transmission line 103 is respectively connected to the demodulation module 104 and the direct current power supply DC. Note that, fig. 4 shows a connection relationship between the first end of the transmission line 103 and the power supply end of the power load 107, that is, shows that the first end of the transmission line 103 may be specifically and electrically connected to the power supply end of the electronic listening circuit 100 and the power supply end of the modulation module 101, respectively, but fig. 4 does not show a connection relationship between the first end of the transmission line 103 and the power supply end of the electronic listening circuit 100 and the power supply end of the modulation module 101, respectively. The modulation module 101 is configured to perform modulation processing on an electrical signal output by the electronic listening circuit 100, and output the modulated electrical signal to the demodulation module 104 through the transmission line 103, so as to perform demodulation processing through the demodulation module 104 and then output the demodulated electrical signal. Specifically, the input of the modulation module 101 may be electrically connected to the output of the signal processing module 10023 in the embodiment shown in fig. 2, or the input of the modulation module 101 may be electrically connected to the output of the amplitude adjustment module 10024 in the embodiment shown in fig. 3, for example. The direct current power supply DC is used to output a direct current voltage signal to a power supply terminal of the power load 107 via the transmission line 103 to supply power to the power load 107 in the probe 10.

For the detector, since the electronic listening circuit 100 is located in the probe 10, and the audio signal (such as the electrical signal described above) acquired by the electronic listening circuit 100 needs to be transmitted to the handle 30 through the connecting rod 20, the handle 30 can be connected to an earphone, so that the detector can listen. However, in the conventional probe, if the audio signal is transmitted using the wire transmission scheme, a separate audio transmission line (which is routed from the probe 10 through the cavity inside the connection rod 20 to the handle 30) is required, and the entire probe is long in length, i.e., has a long transmission line, for which it is required to transmit the audio signal by additionally providing a line, it is relatively complicated. The present embodiment provides the above wired transmission scheme for audio signals, that is, the electrical signal output by the electronic listening circuit 100 may share the transmission line 103 with the dc voltage signal, so that the audio signal output by the listening circuit may be transmitted by using the existing power line in the detector, avoiding additional addition of the audio transmission line, thereby reducing complexity of circuit layout and saving cost.

Further, as shown in fig. 4, the probe 10 is provided with a first isolation unit 102, and may further be provided with a second isolation unit 108. The handle 30 may be provided with a third isolation unit 106 and may be further provided with a fourth isolation unit 105. The first isolation unit 102 is connected between the modulation module 101 and the transmission line 103, specifically, a first end of the first isolation unit 102 is electrically connected to a signal output end of the modulation module 101, and a second end of the first isolation unit 102 is electrically connected to a first end of the transmission line 103 and a power supply end of the power load 107, respectively. The signal output end of the modulation module 101 is used for outputting the modulated electric signal. The first isolation unit 102 includes a capacitor C3.

The second isolation unit 108 is electrically connected between the power supply terminal of the power load 107 and the transmission line 103. Specifically, the first end of the second isolation unit 108 may be electrically connected to the power supply end of the power load 107, and the second end of the second isolation unit 108 may be electrically connected to the second end of the first isolation unit 102 and the first end of the transmission line 103, respectively. The second isolation unit 108 may include an inductive device, such as an inductance L2. It should be noted that, fig. 4 shows that the second isolation unit 108 is electrically connected between the power supply terminal of the power load 107 and the first terminal of the transmission line 103, that is, the power supply terminal of the electronic listening circuit 100 and the power supply terminal of the modulation module 101 are also connected to the first terminal of the transmission line 103 through the second isolation unit 108 (not shown in fig. 4). The first isolation unit 102 is configured to isolate a dc signal, where the first isolation unit 102 may prevent the dc signal related to the power supply from flowing into the modulation module 101 to interfere with the operation of the modulation module 101, and may also prevent the modulation module 101 from outputting the dc signal to the power supply terminal of the power load 107 through the transmission line 103, thereby affecting the normal power supply of the power load 107. The second isolation unit 108 is configured to isolate an ac signal (e.g., an electrical signal output by the modulation module 101) so as to ensure that the power load 107 can be normally powered.

The third isolation unit 106 is electrically connected between the transmission line 103 and the demodulation module 104, specifically, a first end of the third isolation unit 106 is electrically connected to the demodulation module 104, and a second end of the third isolation unit 106 is electrically connected to the second end of the transmission line 103 and the Direct Current (DC) power supply, respectively. The third isolation unit 106 includes, for example, a capacitor C2. The fourth isolation unit 105 is electrically connected between the transmission line 103 and the DC power supply DC, specifically, a first end of the fourth isolation unit 105 is electrically connected to the DC power supply DC, and a second end of the fourth isolation unit 105 may be electrically connected to a second end of the third isolation unit 106 and a second end of the transmission line 103, respectively. The fourth isolation unit 105 includes an inductance L1. In addition, the third isolation unit 106 is configured to isolate the dc signal, and the third isolation unit 106 can prevent various dc signals from flowing into the demodulation module 104, so that the ac signal entering the demodulation module 104 is purer, thereby improving the demodulation accuracy of the demodulation module 104. The fourth isolation unit 105 is configured to isolate an ac signal (such as an electrical signal output by the modulation module 101 transmitted by the transmission line 103) to ensure DC power supply performance of the DC power supply.

In this embodiment, the modulation module 101 modulates an electrical signal output by the electronic listening circuit 100 into a radio frequency signal, and outputs the radio frequency signal to the transmission line 103 for transmission through the capacitor C3, and the transmission line 103 outputs the radio frequency signal to the demodulation module 104 for demodulation through the capacitor C2, so as to obtain an electrical signal in a target frequency band. At the same time, a direct current power supply DC supplies power to the power supply terminal of the power load 107 in the probe 10 through the inductor L1 and the transmission line 103. In addition, since the electric signal transmitted on the transmission line 103 is an ac signal and the dc power supply is a dc signal, even if the transmission directions of the two signals are opposite, the two signals can be independently transmitted, and the two signals do not affect each other. It should be understood that the above is only one embodiment of the present invention, and in other embodiments, only one of the first isolation unit 102 and the second isolation unit 108 may be disposed in the probe 10, and likewise, only one of the third isolation unit 106 and the fourth isolation unit 105 may be disposed in the handle 30. In other embodiments, only the isolation unit (one of the first isolation unit 102 and the second isolation unit 108) may be disposed in the probe 10, and no isolation unit (one of the third isolation unit 106 and the fourth isolation unit 105) may be disposed in the handle 30, or no isolation unit (one of the first isolation unit 102 and the second isolation unit 108) may be disposed in the probe 10, and no isolation unit (one of the third isolation unit 106 and the fourth isolation unit 105) may be disposed in the handle 30, or only the isolation units (e.g., the first isolation unit 102 and the third isolation unit 106) for isolating the dc signal may be disposed in the probe 10 and the handle 30, respectively, or only the isolation units (e.g., the second isolation unit 108 and the fourth isolation unit 105) for isolating the ac signal may be disposed in the probe 10 and the handle 30, respectively.

In this embodiment, if the transmission line 103 is a power line, the electric signal output by the electronic listening circuit 100 may be modulated by the modulation module 101 and then transmitted on the power line, and the audio line may be omitted. Similarly, if the transmission line 103 is an audio line, a direct voltage signal of the direct current power supply DC may be applied to the audio line to supply power to the power supply terminal of the power load 107, and the power supply line may be omitted. The mode of combining the audio line for transmitting the audio electric signal and the power line for supplying power saves cost and energy consumption, and the scheme has higher universality.

Fig. 5 is a schematic circuit diagram of a second embodiment of the detector according to the present invention, where the detector includes a probe 10, a connecting rod 20, and a handle 30 connected in sequence, and a power load 107, a first isolation unit 102, and a second isolation unit 108 are disposed in the probe 10, where the power load 107 includes an electronic listening circuit 100 (not shown in fig. 5) and a modulation module 101, or the power load 107 may also include other functional modules in the probe 10 that need to supply power for operation. It should be noted that, although the electronic listening circuit 100 and the modulation module 101 also belong to one of the power loads 107, for clarity of description of the present embodiment, fig. 5 and the present embodiment also distinguish the electronic listening circuit 100 and the modulation module 101 from the power load 107. A demodulation module 104, a direct current power supply DC, a third isolation unit 106 and a fourth isolation unit 105 are arranged in the handle 30. A transmission line 103 is disposed in the connecting rod 20, and the transmission line 103 is a power line or an audio line. Also, in the detector of this embodiment, the modulation module 101 includes the FM modulation chip U11 and its peripheral circuits (not shown in fig. 5), and the first isolation unit 102 includes the capacitor C3 and the second isolation unit 108 includes the inductor L2. It should be noted that, in fig. 5, only the inductor L2 may be electrically connected between the power supply end of the power load 107 and the first end of the transmission line 103, but in practice, the number of the inductors L2 may be identical to the number of the functional modules in the power load 107, and the power supply end of each functional module in the power load 107 may be electrically connected to the first end of the transmission line 103 through one inductor L2, that is, an inductor L2 (not shown in fig. 5) is also connected between the power supply end of the electronic listening circuit 100 and the first end of the transmission line 103, and an inductor L2 (not shown in fig. 5) is also electrically connected between the power supply end of the modulation module 101 and the transmission line 103. The demodulation module 104 includes an FM demodulation chip U12 and its peripheral circuits (not shown in fig. 5), and the third isolation unit 106 is a capacitor C2, and the fourth isolation unit 105 is an inductor L1.

The working principle of the circuit is as follows: the electronic listening circuit 100 inputs the output Audio signal (audio_in) to the FM modulation chip U11 through the capacitor C5, and modulates the Audio signal with the FM modulation chip U11 to obtain an FM modulation signal with a preset frequency, where the FM modulation signal is a radio frequency signal and also belongs to an ac signal. Since the power supply signal transmitted on the transmission line 103 is a dc signal and the capacitor C3 and the capacitor C2 are blocking capacitors, the dc voltage signal can be prevented from flowing into the FM modulation chip U11. Meanwhile, the capacitor C3 can also avoid the FM modulation chip U11 from outputting other dc signals to the transmission line 103. In addition, if the transmission line 103 is a power line, the direct-current voltage signal output by the direct-current power supply DC supplies power to the power load 107 in the probe 10 through the inductor L1, the transmission line 103 and the inductor L2, and the inductors L1 and L2 can be 1uF inductors, so that the effect of suppressing the FM modulation signal can be achieved, and the FM modulation signal is prevented from entering the power load 107 and the direct-current power supply DC. When the FM modulation signal is input to the FM demodulator U12 through the capacitor C3, the transmission line 103 and the capacitor C2, the FM modulation signal is demodulated by the FM demodulation chip U12 and then restored to be an Audio signal for output, and the restored Audio signal (audio_out) can be directly output to electroacoustic transducer components such as a loudspeaker or the like or can be output to an earphone through an earphone interface, so that the electronic listening function of the detector is realized. In addition, in the principle, the modulation algorithm adopted by the FM modulation chip U11 and the demodulation algorithm adopted by the FM demodulation chip U12 are all adopted by the corresponding existing algorithms, and because the FM modulation signal transmitted on the transmission line 103 is an ac signal and the voltage output by the power supply is a dc signal, even if the transmission directions of the two signals are opposite, independent transmission can be achieved, and the two signals cannot affect each other.

Further, as shown in fig. 5, the FM demodulation chip U12 may further output the restored Audio signal (audio_out) through the capacitor C4, so as to further reduce the dc component in the output Audio signal, thereby ensuring the ac purity of the output Audio signal.

The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any such modifications, equivalents, and improvements that fall within the spirit and principles of the present invention are intended to be covered by the following claims.

Claims

1. The utility model provides an electronic listening circuit which characterized in that, includes transmission route and receiving path, the transmission route is used for transmitting the detection signal of frequency f1 to the target detection thing, the target detection thing exists the target frequency channel that clock frequency is f2, the transmission route includes signal generation module and transmitting antenna, the receiving path includes:

The antenna comprises a receiving antenna, a receiving module and a transmitting module, wherein the receiving antenna is used for receiving electromagnetic wave signals of a preset frequency band, converting the electromagnetic wave signals of the preset frequency band into induction electric signals and outputting the induction electric signals, and the induction electric signals comprise electric signals with the frequency of f1+f2;

The extraction module is electrically connected with the receiving antenna; the extraction module is also electrically connected with a device between the signal generation module and the transmitting antenna, or the extraction module is also electrically connected with the output end of the signal generation module; the extraction module is used for accessing the electric signal with the frequency f1 in the transmission path, and extracting the electric signal containing the target frequency band f2 from the induction electric signal according to the electric signal with the frequency f1 in the transmission path;

and the signal processing module is electrically connected with the extraction module and is used for performing signal processing on the electric signal output by the extraction module so as to obtain the electric signal of the target frequency band f 2.

2. The electronic listening circuit of claim 1, wherein the extraction module comprises:

the first input end of the mixer is electrically connected with the first amplifier; the second input end is electrically connected with a device between the signal generating module and the transmitting antenna, or the second input end is electrically connected with the output end of the signal generating module, and the output end is electrically connected with the signal processing module; the frequency mixer is used for carrying out frequency mixing processing on the induction signal amplified by the first amplifier and the electric signal in the transmitting path so as to remove frequency components which are the same as the electric signal frequency band in the transmitting path in the induction electric signal and obtain the electric signal containing the target frequency band.

3. The electronic listening circuit of claim 2, wherein the transmit path further comprises a first amplification module electrically connected between the signal generation module and the transmit antenna, the second input of the mixer being electrically connected to the output of the first amplification module.

4. The electronic listening circuit of claim 1, wherein the signal processing module comprises a low noise amplifier and a filtering module, an input of the low noise amplifier being electrically connected to an output of the extraction module, an output of the low noise amplifier being electrically connected to the filtering module.

5. The electronic listening circuit of claim 4, wherein the filtering module comprises a first filter and a second filter, and the signal processing module further comprises a second amplifier;

6. The electronic listening circuit of any one of claims 1-5 wherein the receive path further comprises:

7. A detector comprising the electronic listening circuit of any one of claims 1-6.

8. The detector of claim 7, further comprising a probe, a connecting rod and a handle connected in sequence, wherein a power load is arranged in the probe, and the power load comprises the electronic hearing circuit and a modulation module; a demodulation module and a direct current power supply are arranged in the handle; a transmission line is arranged in the connecting rod; the transmission line is a power line or an audio line;

9. The detector of claim 8, wherein at least one of a first isolation unit and a third isolation unit is provided in the detector, wherein a first end of the first isolation unit is electrically connected to the signal output end of the modulation module, and a second end of the first isolation unit is electrically connected to a first end of the transmission line and a power supply end of the power load, respectively; the first end of the third isolation unit is electrically connected with the demodulation module, and the second end of the third isolation unit is electrically connected with the second end of the transmission line and the direct current power supply respectively; the first isolation unit and the third isolation unit are used for isolating direct current signals.

10. The detector of claim 8, wherein at least one of a second isolation unit and a fourth isolation unit is provided in the detector, wherein the second isolation unit is electrically connected between a power supply end of the power load and a first end of the transmission line, and the fourth isolation unit is electrically connected between a second end of the transmission line and the dc power supply; the second isolation unit and the fourth isolation unit are used for isolating alternating current signals.