Signal transmitting circuit, cable detector and waveform adjusting method

Abstract

The invention relates to the technical field of cable detection, and discloses a signal transmitting circuit, a cable detector and a waveform adjusting method, the signal transmitting circuit comprises a signal processing circuit, a signal driving circuit, a signal output circuit and an output waveform adjusting circuit, and the signal output circuit comprises a magnetic core coil L2; the signal processing circuit is used for converting an initial signal output by an external device, generating an oscillation signal and then transmitting the oscillation signal to the magnetic core coil L2 through the signal driving circuit; when the detected cable passes through the magnetic core coil L2, the magnetic core coil L2 loads the oscillation signal to the detected cable, and the output waveform adjusting circuit is used for adjusting the waveform of the oscillation signal. Therefore, the detection signal can be transmitted to the detected cable through the magnetic core coil L2, the signal transmission efficiency and reliability can be improved, the waveform of the oscillation signal can be adjusted, and the signal quality of the detected cable after the oscillation signal is loaded to the detected cable can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of cable detection, and in particular to a signal transmitting circuit, a cable detector, and a waveform adjustment method. Background Art

[0002] In some applications, it's often necessary to use a detection device to detect the desired object or item. Upon detecting the object or item, the device issues a warning to alert the operator. Currently, one of the more common detection devices is a cable detector, which is primarily used to detect cables installed within walls, underground, or ceilings, determining their direction and detecting breakpoints.

[0003] For cable detectors, signals are usually sent through alligator clips. This method requires the alligator clips to clamp the cable being detected, and has high requirements for the contact points between the alligator clips and the cable being detected. If the contact points are oxidized or oily, the contact between the alligator clips and the cable being detected will be unstable, thereby affecting the signal transmission efficiency and reliability.

[0004] It can be seen that when realizing cable detection, how to improve signal transmission efficiency and signal transmission reliability is particularly important. Summary of the Invention

[0005] The present invention provides a signal transmission circuit, a cable detector, and a waveform adjustment method, which can improve the signal transmission efficiency and signal transmission reliability between the cable detector and the detected cable.

[0006] In order to solve the above technical problems, the first aspect of the present invention discloses a signal transmitting circuit, the signal transmitting circuit comprising:

[0007] A signal processing circuit, a signal driving circuit, a signal output circuit, and an output waveform adjustment circuit; the signal input end of the signal processing circuit is used to receive the initial signal output by an external device, and the signal output end of the signal processing circuit is electrically connected to the signal input end of the signal driving circuit; the signal output end of the signal driving circuit is electrically connected to the signal output circuit; and the output waveform adjustment circuit is electrically connected to the signal processing circuit;

[0008] In which, the signal output circuit includes a magnetic core coil L2; the signal processing circuit is used to convert and process the initial signal to generate an oscillation signal; the oscillation signal is transmitted to the magnetic core coil L2 via the signal driving circuit; the magnetic core coil L2 is used to load the oscillation signal onto the detected cable when the detected cable passes through the magnetic core coil L2; the output waveform adjustment circuit is used to adjust the waveform of the oscillation signal.

[0009] As an optional embodiment, in the first aspect of the present invention, the signal processing circuit includes a signal generating circuit, or the signal processing circuit includes a signal generating circuit and a filtering circuit electrically connected to the signal generating circuit;

[0010] The signal generating circuit is used to perform signal conversion on the initial signal to obtain a converted signal, and perform frequency-selective amplification on the converted signal to generate an oscillation signal.

[0011] As an optional implementation manner, in the first aspect of the present invention, the signal processing circuit further includes:

[0012] a signal amplifying circuit, wherein a signal input end of the signal amplifying circuit is electrically connected to the signal generating circuit, and a signal output end of the signal amplifying circuit is electrically connected to the signal driving circuit;

[0013] The signal amplifying circuit is used to amplify the oscillation signal and transmit the amplified oscillation signal to the signal driving circuit.

[0014] As an optional implementation manner, in the first aspect of the present invention, the signal transmitting circuit further includes:

[0015] a voltage regulating circuit, wherein a signal input terminal of the voltage regulating circuit is used to receive a DC voltage, and a signal output terminal of the voltage regulating circuit is electrically connected to the signal processing circuit, the signal driving circuit, and the voltage terminal of the signal output circuit;

[0016] The voltage regulating circuit is used to adjust the DC voltage to the emission voltage required for object detection, and provide it to the signal processing circuit, the signal driving circuit and the signal output circuit.

[0017] As an optional embodiment, in the first aspect of the present invention, the filtering circuit includes a capacitor C4 and a resistor R8 connected in parallel;

[0018] and / or,

[0019] The signal generating circuit includes a common-emitter amplifier circuit and an LC oscillation circuit.

[0020] As an optional embodiment, in the first aspect of the present invention, the common-emitter amplifier circuit includes a transistor Q3, and the LC oscillator circuit includes a capacitor C5 and a coil L1 connected in parallel;

[0021] One end of the LC oscillation circuit is electrically connected to the collector of the transistor Q3 , the base of the transistor Q3 is used to access the initial signal, and the emitter of the transistor Q3 is used to be grounded.

[0022] As an optional implementation, the signal driving circuit includes a complementary symmetrical power amplifier circuit; the complementary symmetrical power amplifier circuit 201 includes: a transistor Q5 and a transistor Q6, and the transistor Q5 and the transistor Q6 constitute a complementary symmetrical power amplifier circuit;

[0023] Among them, the base of the transistor Q5 is electrically connected to the signal processing circuit, and the emitter of the transistor Q5 is electrically connected to the signal output circuit; the emitter of the transistor Q6 is electrically connected to the signal output circuit, and the base of the transistor Q6 is electrically connected to the signal processing circuit.

[0024] As an optional implementation, in the first aspect of the present invention, the signal output circuit further includes: an alligator clip connected in parallel with the magnetic core coil L2.

[0025] As an optional implementation manner, in the first aspect of the present invention, the voltage regulating circuit includes:

[0026] Transistor Q1, transistor Q2, resistor R1, Zener diode DZ1, resistor R2 and variable resistor RP1;

[0027] Wherein, one end of the resistor R1 is electrically connected to the collector of the transistor Q1 and is used to receive the DC voltage, and the other end of the resistor R1 is electrically connected to the collector of the transistor Q2 and the base of the transistor Q1; the emitter of the transistor Q1 is electrically connected to one end of the resistor R2, the first end of the variable resistor RP1, and the first voltage end of the signal processing circuit, the signal driving circuit, and the signal output circuit; the base of the transistor Q2 is electrically connected to the adjustment end of the variable resistor RP1, and the emitter of the transistor Q2 is electrically connected to the cathode of the Zener diode DZ1 and the other end of the resistor R2; the anode of the Zener diode DZ1 is electrically connected to the second end of the variable resistor RP1 and the second voltage end of the signal processing circuit, the signal driving circuit, and the signal output circuit;

[0028] Furthermore, the voltage regulating circuit further includes a resistor R15 , one end of the resistor R15 is electrically connected to the base of the transistor Q1 , and the other end of the resistor R15 is electrically connected to the other end of the resistor R1 and the collector of the transistor Q2 .

[0029] As an optional embodiment, in the first aspect of the present invention, the output waveform adjustment circuit includes: a resistor R17, a resistor R18 and a capacitor C11;

[0030] Among them, one end of the resistor R17 is electrically connected to the collector of the transistor Q3, and the other end of the resistor R17 is electrically connected to one end of the resistor R18 and one end of the capacitor C11 respectively; the other end of the capacitor C11 is electrically connected to the signal input end of the signal amplifying circuit; the other end of the resistor R18 is used for grounding.

[0031] As an optional implementation manner, in the first aspect of the present invention, the output waveform adjustment circuit further includes:

[0032] a resistor R16, one end of the resistor R16 being electrically connected to the emitter of the transistor Q3, and the other end of the resistor R16 being grounded;

[0033] or,

[0034] a capacitor C6, one end of the capacitor C6 being grounded, and the other end of the capacitor C6 being electrically connected to the emitter of the transistor Q3;

[0035] or;

[0036] A resistor R16 and a capacitor C6, one end of the resistor R16 is electrically connected to the emitter of the transistor Q3, one end of the capacitor C6 is grounded, and the other end of the capacitor C6 is electrically connected to the other end of the resistor R16.

[0037] A second aspect of the present invention discloses a cable detector, which includes a device body and the signal transmission circuit described in any one of the first aspects of the present invention.

[0038] A third aspect of the present invention discloses a waveform adjustment method, which is applied to a signal transmitter, wherein the signal transmitter includes the signal transmission circuit according to any one of the first aspects of the present invention, and the method includes:

[0039] Step 1: amplifying and converting the initial signal output by the external device through the signal processing circuit to obtain an oscillation signal;

[0040] Step 2: amplifying the power of the oscillation signal by the signal driving circuit to obtain a power amplified signal;

[0041] Step 3: Output the power amplified signal to the detected cable through a wire connected in parallel with the magnetic core coil L2 to obtain a signal on the detected cable;

[0042] If the waveform of the signal on the detected cable does not meet the preset waveform conditions, the parameters of the target device in the signal processing circuit and / or the output waveform adjustment circuit are adjusted, and steps 1, 2, and 3 are re-executed until the waveform of the signal on the detected cable meets the preset waveform conditions.

[0043] As an optional embodiment, in the third aspect of the present invention, the waveform of the signal on the detected cable satisfies the preset waveform condition, including that the amplitude difference between the waveform of the signal on the detected cable and the waveform of the power amplified signal output to the detected cable is within a preset amplitude range.

[0044] The implementation of the present invention has the following beneficial effects:

[0045] The signal transmitting circuit disclosed in the present invention is applied to a cable detector, and the signal transmitting circuit includes a signal processing circuit, a signal driving circuit, a signal output circuit and an output waveform adjustment circuit, and the signal output circuit includes a magnetic core coil L2; the signal processing circuit is used to convert and process the initial signal output by an external device to generate an oscillation signal; the oscillation signal is transmitted to the magnetic core coil L2 via the signal driving circuit; when the detected cable passes through the magnetic core coil L2, the magnetic core coil L2 loads the oscillation signal onto the detected cable; in addition, the output waveform adjustment circuit is used to adjust the waveform of the oscillation signal so that after the oscillation signal is loaded onto the detected cable, the waveform of the signal on the detected cable meets a preset waveform condition. It can be seen that the present invention can transmit the detection signal to the detected cable through the magnetic core coil. Compared with the crocodile clip method, it is not only beneficial to improve the signal transmission efficiency, signal transmission reliability and signal transmission stability between the cable detector and the detected cable, but also does not need to destroy the line of the detected cable. It only needs to pass the cable to be detected through the middle hole of the magnetic core coil L2, and can also realize simultaneous detection of multiple cables or wire cores, with a wider range of applicable scenarios; in addition, it can also adjust the waveform of the oscillation signal so that after the oscillation signal is loaded onto the detected cable, the waveform of the signal on the detected cable meets the preset waveform condition, which is beneficial to improve the signal quality on the detected cable after the oscillation signal is loaded onto the detected cable, and thus is beneficial to improving the cable detection effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0047] Figure 1 This is a structural diagram of a signal transmission circuit disclosed in an embodiment of the present invention;

[0048] Figure 2 is a structural diagram of another signal transmission circuit disclosed in an embodiment of the present invention;

[0049] Figure 3 This is a flow chart of a waveform adjustment method disclosed in an embodiment of the present invention;

[0050] Figure 4 This is a waveform comparison diagram disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0051] For better understanding and implementation, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0052] It should be noted that, unless otherwise expressly specified and limited, the term "electrical connection" in the specification and claims of the present invention and the above-mentioned drawings should be understood in a broad sense. For example, it can be a fixed electrical connection, a detachable electrical connection or an integral electrical connection; it can be a mechanical electrical connection or a mutual communication connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. In addition, the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. The terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0053] The present invention discloses a signal transmitting circuit, a cable detector, and a waveform adjustment method, which can transmit a detection signal to a detected cable through a magnetic core coil. Compared with the crocodile clip method, it is not only conducive to improving the signal transmission efficiency, signal transmission reliability, and signal transmission stability between the cable detector and the detected cable, but also does not need to destroy the line of the detected cable. It only needs to pass the cable to be detected through the middle hole of the magnetic core coil L2, and can also realize simultaneous detection of multiple cables or wire cores, with a wider range of applicable scenarios; in addition, it is also possible to adjust the waveform of the oscillation signal so that after the oscillation signal is loaded onto the detected cable, the waveform of the signal on the detected cable meets the preset waveform condition, which is conducive to improving the signal quality on the detected cable after the oscillation signal is loaded onto the detected cable, and thus is conducive to improving the cable detection effect. The following are detailed descriptions.

[0054] Example 1

[0055] See also Figure 1 , Figure 1This is a schematic diagram of the structure of a signal transmitting circuit disclosed in an embodiment of the present invention. The signal transmitting circuit is applied to a cable detector. More specifically, the signal transmitting circuit is applied to a signal transmitter of the cable detector to realize signal transmission between the cable detector and the detected cable, thereby realizing detection of the detected cable. Figure 1 As shown, the signal transmitting circuit may include:

[0056] A signal processing circuit 10, a signal driving circuit 20, and a signal output circuit 30; the signal input end of the signal processing circuit 10 is used to access the initial signal output by an external device, and the signal output end of the signal processing circuit 10 is electrically connected to the signal input end of the signal driving circuit 20; the signal output end of the signal driving circuit 20 is electrically connected to the signal output circuit 30; wherein, the signal output circuit 30 may include a magnetic core coil L2, or the signal output circuit 30 may include a magnetic core coil L2 and an alligator clip connected in parallel with the magnetic core coil L2 (not shown in the figure).

[0057] In an embodiment of the present invention, the signal processing circuit 10 is used to convert and process the initial signal output by the external device to generate an oscillation signal; the oscillation signal is transmitted to the magnetic core coil L2 through the signal driving circuit 20; the magnetic core coil L2 is used to load the oscillation signal onto the detected cable when the detected cable passes through the magnetic core coil L2.

[0058] Optionally, the signal transmission circuit may further include an output waveform adjustment circuit 40. The output waveform adjustment circuit 40 is electrically connected to the signal processing circuit 10 and configured to adjust the waveform of the oscillating signal so that, after the oscillating signal is applied to the detected cable, the waveform of the signal on the detected cable satisfies a preset waveform condition. Furthermore, optionally, the waveform of the signal on the detected cable satisfying the preset waveform condition may include the amplitude difference between the waveform of the signal on the detected cable and the waveform of the oscillating signal output to the detected cable being within a preset amplitude range. After the signal transmitted by the existing signal transmitter is output to the detected cable, the waveform of the signal will be distorted due to the interference of the detected cable. The waveform distortion will cause the phase, amplitude or frequency characteristics of the signal received by the signal receiver of the cable detector to change, resulting in confusion of signals of different cables in complex pipeline environments (such as multiple cables crossing or running in parallel), which in turn makes it difficult for the signal receiver to determine the cable corresponding to the signal. Furthermore, the waveform distortion will be accompanied by signal energy dispersion (such as harmonic interference or impedance mismatch), resulting in a shortened effective detection distance and the inability to detect long-distance cables. That is, the existing signal transmitter has the problem of poor cable detection effect due to the distortion of the signal waveform transmitted to the detected cable. In the embodiment of the present invention, the output waveform adjustment circuit 40 is provided in the signal transmission circuit of the signal transmitter to adjust the waveform of the oscillating signal loaded on the detected cable, thereby reducing the occurrence of signal waveform distortion on the detected cable caused by interference from the detected cable, which is conducive to improving the cable detection effect, such as improving the accuracy of cable detection and effectively increasing the cable detection distance.

[0059] In an embodiment of the present invention, the initial signal output by the external device (also known as a "signal generator") can also be understood as a detection trigger signal, and the initial signal can be specifically generated by the external device controlled by the single-chip microcomputer and output to the signal processing circuit 10. Optionally, the initial signal can be an AM (medium wave) or FM (short wave) signal from 1KHz to 30MHz, and the specific frequency range can be selected or adjusted according to actual needs or actual application scenarios, which is not limited in the embodiment of the present invention. Furthermore, the initial signal can be a square wave signal or a sine wave signal.

[0060] It can be seen that the embodiment of the present invention can transmit the detection signal to the detected cable through the magnetic core coil. Compared with the alligator clip method, it is not only conducive to improving the signal transmission efficiency, signal transmission reliability and signal transmission stability between the cable detector and the detected cable, but also does not need to destroy the line of the detected cable. It only needs to pass the cable to be detected through the middle hole of the magnetic core coil L2. It can also achieve simultaneous detection of multiple cables or wire cores, and has a wider range of applicable scenarios. In addition, in addition to including the magnetic core coil L2, the signal output circuit 30 can further include an alligator clip, which enables the signal transmission circuit to have at least two signal transmission modes, which is conducive to improving the flexibility of signal transmission, and thus is conducive to improving the flexibility of cable detection. In addition, the waveform of the oscillation signal can be adjusted so that after the oscillation signal is loaded onto the detected cable, the waveform of the signal on the detected cable meets the preset waveform condition, which is conducive to improving the signal quality on the detected cable after the oscillation signal is loaded onto the detected cable, and thus is conducive to improving the cable detection effect.

[0061] In an optional embodiment, the signal processing circuit 10 may include a signal generating circuit 101, and further, may include a filtering circuit 102 electrically connected to the signal generating circuit 101;

[0062] Among them, the signal generating circuit 101 is used to convert the initial signal to obtain a converted signal, and perform frequency-selective amplification on the converted signal to generate an oscillation signal; the oscillation signal is transmitted to the signal output circuit 30 via the signal driving circuit 20; the signal output circuit 30 is used to load the oscillation signal onto the detected cable.

[0063] In an embodiment of the present invention, the initial signal output by the external device is preferably a square wave signal. Signal generation circuit 101 specifically converts the square wave signal output by the external device into an analog sinusoidal signal and performs frequency-selective amplification on the signal to generate an oscillation signal within a certain oscillation frequency range. Furthermore, filter circuit 102 is optionally configured to implement signal filtering to reduce signal interference and improve signal quality.

[0064] It can be seen that this optional embodiment of the invention can also perform frequency-selective amplification on specific frequency signals, enhance useful signals, suppress interference signals, and thus help improve signal quality.

[0065] In another optional embodiment, Figure 2As shown, the above-mentioned signal processing circuit 10 may further include a signal amplifying circuit 103 (also referred to as a push-pull preamplifying circuit), the signal input end of the signal amplifying circuit 103 is electrically connected to the signal generating circuit 101, and the signal output end of the signal amplifying circuit 103 is electrically connected to the signal driving circuit 20; wherein, the signal amplifying circuit 103 is used to amplify the oscillation signal and transmit the amplified oscillation signal to the signal driving circuit 20. Optionally, the signal amplifying circuit 103 and the signal generating circuit 101 may be connected via Figure 2 The coupling capacitor C7 shown in the figure is electrically connected, which not only ensures stable signal transmission, but also filters out noise signals and reduces interference.

[0066] In this optional embodiment, further optional, such as Figure 2 As shown, the signal amplifying circuit 103 may include a transistor Q4; wherein the base of the transistor Q4 is electrically connected to the signal generating circuit 101, the collector of the transistor Q4 is electrically connected to the signal input terminal of the signal driving circuit 20, and the emitter of the transistor Q4 is grounded. Further optionally, the signal amplifying circuit 103 may further include other electronic components for assisting in achieving the signal amplification function, for details, please refer to Figure 2 The resistor R10 and the resistor R11 shown in the figure can set a suitable static operating point for the transistor Q4, so that the transistor Q4 works in a suitable amplification area, further improves the signal amplitude, and prepares for the subsequent power amplification.

[0067] It can be seen that the signal processing circuit 10 in this optional embodiment can improve the signal driving capability through the signal amplification circuit 103, which is conducive to improving signal transmission reliability. In addition, the signal amplification is achieved through the transistor, which has a simple structure and is conducive to reducing the complexity of the signal transmission circuit and saving costs.

[0068] In another optional embodiment, Figure 2 As shown, the signal transmitting circuit may further include:

[0069] The voltage regulating circuit 50 has a signal input terminal for receiving a DC voltage, and a signal output terminal for electrically connecting the signal processing circuit 10, the signal driving circuit 20, and the voltage terminal of the signal output circuit 30; wherein, the voltage regulating circuit 50 is used to adjust the DC voltage to the emission voltage required for object detection, and provide it to the signal processing circuit 10, the signal driving circuit 20, and the signal output circuit 30.

[0070] In this optional embodiment, further optional, such as Figure 2 As shown, the voltage regulating circuit 50 may include:

[0071] Transistor Q1, transistor Q2, resistor R1, Zener diode DZ1, resistor R2 and variable resistor RP1;

[0072] Among them, one end of the resistor R1 is electrically connected to the collector of the transistor Q1 and is used to access the DC voltage, and the other end of the resistor R1 is electrically connected to the collector of the transistor Q2 and the base of the transistor Q1; the emitter of the transistor Q1 is electrically connected to one end of the resistor R2, the first end of the variable resistor RP1, and the first voltage end of the signal processing circuit 10, the signal driving circuit 20, and the signal output circuit 30; the base of the transistor Q2 is electrically connected to the adjustment end of the variable resistor RP1, and the emitter of the transistor Q2 is electrically connected to the cathode of the Zener diode DZ1 and the other end of the resistor R2; the anode of the Zener diode DZ1 is electrically connected to the second end of the variable resistor RP1 and the second voltage end of the signal processing circuit 10, the signal driving circuit 20, and the signal output circuit 30.

[0073] In this optional embodiment, transistor Q1 and transistor Q2 form a composite transistor that adjusts the output voltage; resistor R1 provides bias current for transistor Q1; voltage regulator diode DZ1 provides a stable reference voltage for the base of transistor Q2; resistor RP1 is a variable resistor with an adjustable resistance. By adjusting the resistance of variable resistor RP1, the potential of the base of transistor Q can be changed, thereby adjusting the output voltage and achieving a voltage stabilization function for the entire circuit.

[0074] In this optional embodiment, it is further optional, as Figure 2 As shown, the voltage regulation circuit 50 further includes a resistor R15, one end of which is electrically connected to the base of the transistor Q1, and the other end of which is electrically connected to the other end of the resistor R1 and the collector of the transistor Q2. Resistor R15 primarily serves to limit the base current of the transistor Q2. By setting a suitable resistance value for resistor R15, the transistor Q2 can be ensured to operate in a suitable bias state, thereby reducing the possibility that excessive or insufficient base current could prevent the transistor Q2 from properly performing its amplification function and thus affect the operation of the entire circuit. Furthermore, the addition of resistor R15 can reduce the standby power consumption of the signal transmission circuit.

[0075] As can be seen, this optional embodiment can not only provide a stable transmit voltage through the voltage regulation circuit 50, but also adjust the transmit voltage through the variable resistor RP1, which is beneficial for improving the flexibility and convenience of adjusting the signal strength. In addition, it can ensure that the transistor Q2 operates in a suitable bias state, reducing the possibility that the transistor Q2 cannot properly perform functions such as amplification due to excessive or insufficient base current, thereby affecting the operating state of the entire circuit. It can also reduce the standby power consumption of the signal transmission circuit.

[0076] In another optional embodiment, Figure 2 As shown, the signal generating circuit 101 includes a common-emitter amplifier circuit 1011 and an LC oscillator circuit 1012 .

[0077] In this optional embodiment, further optionally, the common-emitter amplifier circuit 1011 includes a transistor Q3, and the LC oscillator circuit 1012 includes a capacitor C5 and a coil L1 connected in parallel; wherein one end of the LC oscillator circuit 1012 is electrically connected to the collector of the transistor Q3, the base of the transistor Q3 is used to receive the initial signal, and the emitter of the transistor Q3 is used to be grounded. Optionally, the initial signal can be passed through Figure 2 The coupling capacitor C3 shown in FIG is input to the base of the transistor Q3.

[0078] Alternatively, the common-emitter amplifier circuit 1011 may further include a voltage divider circuit formed by connecting resistors R5 and R6 in series to provide a suitable bias voltage for the transistor Q3. Thus, the voltage divider circuit provides a stable base bias voltage for the transistor Q3, thereby controlling the conduction between the collector and emitter of the transistor Q3, thereby facilitating the generation and control of the oscillation signal. Alternatively, as Figure 2 As shown, the common-emitter amplifier circuit 1011 may further include a negative feedback circuit composed of a resistor R7 and a capacitor C6 to stabilize the operating point of the transistor Q3 and improve the performance of the common-emitter amplifier circuit 1011.

[0079] As can be seen, this optional embodiment can achieve switching and signal amplification functions through transistor Q3, thereby flexibly controlling the generation of the oscillation signal. Furthermore, the oscillation circuit (also known as a resonant circuit) formed by the parallel connection of capacitor C5 and coil L1 achieves frequency selection of specific frequency signals and amplifies the specific frequency signal through transistor Q3, thereby enhancing the useful signal and suppressing interference signals, thereby improving the stability and reliability of signal transmission.

[0080] In another optional embodiment, Figure 2 As shown, the filter circuit 102 may include a capacitor C4 and a resistor R8 connected in parallel. It can be seen that this optional embodiment can filter out interference signals through the filter circuit 102 and has a simple structure.

[0081] In another optional embodiment, Figure 2As shown, the signal driving circuit 20 includes a complementary symmetrical power amplifier circuit 201. Optionally, the complementary symmetrical power amplifier circuit 201 may include a transistor Q5 and a transistor Q6; the base of the transistor Q5 is electrically connected to the signal processing circuit 10, and the emitter of the transistor Q5 is electrically connected to the signal output circuit 30; the emitter of the transistor Q6 is electrically connected to the signal output circuit 30, and the base of the transistor Q6 is electrically connected to the signal processing circuit 10. Further optionally, the signal driving circuit 20 also includes a bias voltage providing circuit 202;

[0082] A first end of the bias voltage providing circuit 202 is electrically connected to the base of the transistor Q5, and a second end of the bias voltage providing circuit is electrically connected to the base of the transistor Q6 and the signal output end of the signal processing circuit 10 (i.e., the collector of the transistor Q4);

[0083] Further optional, such as Figure 2 As shown, the bias voltage providing circuit 202 may include a diode VD1 and a diode VD2 connected in series, wherein the anode of the diode VD1 serves as a first terminal of the bias voltage providing circuit 202, and the cathode of the diode VD2 serves as a second terminal of the bias voltage providing circuit 202. The bias voltage providing circuit 202 composed of the diodes VD1 and VD2 can provide bias voltages for the transistors Q5 and Q6, thereby driving the transistors Q5 and Q6 to conduct during corresponding signal cycles.

[0084] In this optional embodiment, further optionally, transistor Q5 is an NPN transistor, transistor Q6 is a PNP transistor, and transistor Q5 and transistor Q6 form a complementary symmetrical power amplifier circuit. When in the positive half cycle of the oscillation signal, the base potential of transistor Q5 increases, and after meeting the conduction condition, transistor Q5 starts to conduct. At this time, transistor Q5 performs power amplification on the signal from the intermediate amplifier (i.e., transistor Q4), obtains current from the power supply, and outputs the amplified current to the magnetic core coil L2 through capacitor C9, driving the magnetic core coil L2 to work. When entering the negative half cycle of the oscillation signal, the base potential of transistor Q6 decreases, and turns on after meeting the conduction condition. It performs power amplification on the negative half cycle signal, obtains reverse current from the circuit and outputs it to the magnetic core coil L2 through capacitor C9, continuing to drive the load to work. That is, transistor Q5 and transistor Q6 work in a complementary manner. The two cooperate with each other and alternately conduct within a complete signal cycle to provide continuous driving current to the magnetic core coil L2, thereby reducing the occurrence of signal distortion and ensuring that the magnetic core coil L2 can accurately restore the input signal.

[0085] It can be seen that this optional embodiment can not only amplify the signal through the transistor Q5 and the transistor Q6 in the signal driving circuit 20, but also alternately conduct within a complete signal cycle to provide continuous driving current to the magnetic core coil L2, thereby reducing the occurrence of signal distortion and ensuring that the magnetic core coil L2 can accurately restore the input signal.

[0086] In another optional embodiment, Figure 2 As shown, the output waveform adjustment circuit 40 may include a resistor R17, a resistor R18, and a capacitor C11. One end of the resistor R17 is electrically connected to the collector of the transistor Q3, and the other end of the resistor R17 is electrically connected to one end of the resistor R18 and one end of the capacitor C11. The other end of the capacitor C11 is electrically connected to the signal input terminal of the signal amplifying circuit 103. The other end of the resistor R18 is grounded.

[0087] In this optional embodiment, resistor R17 plays the role of current limiting and impedance matching in the signal transmission path, preventing damage to the subsequent circuit due to problems such as excessive current during signal transmission, and making the impedance between the signal source and the load reach a suitable matching state, reducing signal reflection and the like; resistor R18 cooperates with transistor Q4 to set the base bias voltage of transistor Q4, determine the static operating point of transistor Q4, and ensure that transistor Q4 can normally amplify the input signal; capacitor C11 is a coupling capacitor, whose function is to isolate DC signals and only allow AC signals to pass through, transmitting the AC signal of the previous circuit (such as the signal processed by components such as resistor R17) to the base of transistor Q4, while preventing the DC operating points of the previous and subsequent circuits from affecting each other.

[0088] Further optional, such as Figure 2 As shown, the output waveform adjustment circuit 40 may further include:

[0089] a resistor R16, one end of the resistor R16 being electrically connected to the emitter of the transistor Q3, and the other end of the resistor R16 being grounded;

[0090] or,

[0091] Capacitor C6, one end of the capacitor C6 is grounded, and the other end of the capacitor C6 is electrically connected to the emitter of the transistor Q3;

[0092] or;

[0093] The resistor R16 and the capacitor C6 have one end electrically connected to the emitter of the transistor Q3 , one end of the capacitor C6 is grounded, and the other end of the capacitor C6 is electrically connected to the other end of the resistor R16 .

[0094] In this optional embodiment, resistor R16 is in the collector circuit of transistor Q3, and plays the role of converting the change of the collector current of transistor Q3 into a voltage change, so as to transmit the amplified signal to the subsequent circuit, and also affects the operating point of transistor Q3; capacitor C6 is a bypass capacitor, which is equivalent to a short circuit for AC signals, and can allow the AC signal of the collector of transistor Q3 to pass smoothly while blocking the DC component, ensuring the stability of the DC voltage on resistor R16, stabilizing the operating point of transistor Q3, and allowing the AC signal to be transmitted to the subsequent circuit without attenuation.

[0095] It should be noted that some or all of the components in the output waveform adjustment circuit 40 may be components with fixed parameters or components with variable parameters.

[0096] Among them, this optional embodiment can shape and adjust the waveform of the output signal through the parameters of relevant components in the output waveform adjustment circuit 40 to improve the signal quality on the detected cable after the oscillation signal is loaded onto the detected cable, and the waveform adjustment method is relatively convenient and low-cost.

[0097] In yet another optional embodiment, when adjusting the waveform of the signal output by the signal transmitting circuit, it may also be achieved by changing the resistance value of the resistor R11 and / or the capacitance value of the capacitor C10 in the signal amplifying circuit 103 .

[0098] Among them, increasing the resistance value of resistor R11 can enhance the AC negative feedback of the emitter of transistor Q4. When realizing cable detection, the problem of increased signal amplitude introduced by multi-core cables can be solved by reducing the amplification factor of transistor Q4 due to the enhanced AC negative feedback, thereby reducing the output signal amplitude and alleviating amplitude abnormality; in addition, the nonlinear distortion caused by the detected cable can also be corrected to a certain extent by improving the linearity of transistor Q4 due to the AC negative feedback; reducing the resistance value of resistor R11 can weaken the AC negative feedback of the emitter of transistor Q4 and increase the amplification factor of transistor Q4. When realizing cable detection, if the multi-core cable attenuates the signal amplitude, the resistance value of resistor R11 can be appropriately reduced, thereby increasing the signal amplitude.

[0099] In this optional embodiment, when adjusting the capacitance of capacitor C10, increasing its value reduces its capacitive reactance in the low-frequency range, weakening the negative AC feedback effect of resistor R11 in the low-frequency range. During actual cable detection, if multi-core cables attenuate the low-frequency components of the signal, increasing the capacitance of capacitor C10 can relatively increase the low-frequency amplitude of the output signal, compensating for low-frequency losses and thereby improving signal quality.

[0100] It should be noted that: in other optional embodiments, the signal transmission circuit may not include the output waveform adjustment circuit 40. When the signal waveform needs to be adjusted, it can be achieved directly by changing the resistance value of the resistor R11 and / or the capacitance value of the capacitor C10 in the signal amplification circuit 103.

[0101] It can be seen that this optional embodiment can adjust the signal waveform by changing the resistance value of the resistor R11 and / or the capacitance value of the capacitor C10 in the signal amplification circuit 103, which is beneficial to improving the signal quality, and the waveform adjustment method is relatively convenient and low-cost.

[0102] Example 2

[0103] An embodiment of the present invention discloses a cable detector, which includes a device body and any signal transmission circuit described in the first embodiment.

[0104] Example 3

[0105] See also Figure 3 , Figure 3 This is a waveform adjustment method disclosed in an embodiment of the present invention. Figure 3 The waveform adjustment method shown is applied to a signal transmitter, which includes any signal transmission circuit described in the first embodiment. Figure 3 As shown, the waveform adjustment method may include:

[0106] 601. Amplify and convert the initial signal output by the external device through the signal processing circuit 10 to obtain an oscillation signal;

[0107] 602. Power amplify the oscillation signal through the signal driving circuit 20 to obtain a power amplified signal;

[0108] 603. Output the power amplified signal to the detected cable through a wire connected in parallel with the magnetic core coil L2 to obtain a signal on the detected cable.

[0109] In the embodiment of the present invention, if the waveform of the signal on the detection cable does not meet the preset waveform condition, step 604 is executed. If the waveform of the signal on the detection cable meets the preset waveform condition, the waveform adjustment process may be terminated.

[0110] 604 . Adjust parameters of target devices in the signal processing circuit 10 and / or the output waveform adjustment circuit 40 .

[0111] In the embodiment of the present invention, after the step of adjusting the target device parameters is completed, steps 601 to 603 may be restarted until the waveform of the signal on the detected cable meets a preset waveform condition.

[0112] In the embodiment of the present invention, the waveform of the signal on the detected cable satisfies the preset waveform condition, which includes that the amplitude difference between the waveform of the signal on the detected cable and the waveform of the power amplified signal output to the detected cable is within a preset amplitude range.

[0113] Among them, the waveform comparison when adjusting the waveform by adjusting the device parameters can be referred to Figure 4 As shown. Among them, Figure 4 4-A in the figure is a schematic diagram of the signal waveform output by the signal transmitting circuit when it is unloaded after adjusting the device parameters. Figure 4 Figure 4-B shows the waveform of the signal on the detected cable after the signal output from the signal transmission circuit is applied to the detected cable after adjusting the device parameters. The waveform in Figure 4-B differs from that in Figure 4-A in that the waveform becomes smoother after the detected cable is connected. This smoothes the waveform and eliminates noise after the detected cable is connected, improving signal quality and cable detection effectiveness.

[0114] It should be noted that: for the detailed description of the signal transmission circuit in the embodiment of the present invention and the detailed description of the components whose parameters need to be adjusted when adjusting the waveform, reference can be made to the relevant description in the aforementioned embodiment 1, and the embodiment of the present invention will not be repeated here.

[0115] As can be seen, the embodiments of the present invention can adjust the waveform of the power amplified signal by adjusting the parameters of relevant components when the signal waveform on the detected cable does not meet preset waveform conditions. This can further adjust the waveform of the signal on the detected cable. This helps reduce the occurrence of signal waveform distortion on the detected cable caused by interference from the detected cable, and is beneficial for improving cable detection results, such as increasing cable detection accuracy and effectively increasing cable detection distance. In addition, the waveform adjustment method is relatively convenient and low-cost.

[0116] The above is a detailed introduction to a signal transmission circuit, a cable detector, and a waveform adjustment method disclosed in an embodiment of the present invention. Specific embodiments are used herein to illustrate the principles and implementation methods of the present invention. However, the above preferred embodiments are not intended to limit the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, based on the ideas of the present invention, without departing from the spirit and scope of the present invention, there may be changes in the specific implementation methods and application scopes. Therefore, the scope of protection of the present invention shall be based on the scope defined by the claims.

Claims

1. A signal transmitting circuit, characterized in that: The signal transmitting circuit includes: A signal processing circuit (10), a signal driving circuit (20), a signal output circuit (30) and an output waveform adjustment circuit (40); the signal input end of the signal processing circuit (10) is used to receive an initial signal output by an external device, the signal output end of the signal processing circuit (10) is electrically connected to the signal input end of the signal driving circuit (20); the signal output end of the signal driving circuit (20) is electrically connected to the signal output circuit (30); the output waveform adjustment circuit (40) is electrically connected to the signal processing circuit (10); The signal output circuit (30) includes a magnetic core coil L2; the signal processing circuit (10) is used to convert the initial signal to generate an oscillation signal; the oscillation signal is transmitted to the magnetic core coil L2 via the signal driving circuit (20); the magnetic core coil L2 is used to load the oscillation signal onto the detected cable when the detected cable passes through the magnetic core coil L2; and the output waveform adjustment circuit (40) is used to adjust the waveform of the oscillation signal.

2. The signal transmitting circuit according to claim 1, wherein: The signal processing circuit (10) includes a signal generating circuit (101), or the signal processing circuit (10) includes a signal generating circuit (101) and a filter circuit (102) electrically connected to the signal generating circuit (101); The signal generating circuit (101) is used to perform signal conversion on the initial signal to obtain a converted signal, and perform frequency-selective amplification on the converted signal to generate an oscillation signal.

3. The signal transmitting circuit according to claim 2, wherein: The signal processing circuit (10) further includes: a signal amplifying circuit (103), wherein a signal input end of the signal amplifying circuit (103) is electrically connected to the signal generating circuit (101), and a signal output end of the signal amplifying circuit (103) is electrically connected to the signal driving circuit (20); The signal amplifying circuit (103) is used to amplify the oscillation signal and transmit the amplified oscillation signal to the signal driving circuit (20).

4. The signal transmitting circuit according to any one of claims 1 to 3, characterized in that: The signal transmitting circuit further includes: A voltage regulating circuit (50), wherein a signal input end of the voltage regulating circuit (50) is used to receive a DC voltage, and a signal output end of the voltage regulating circuit (50) is electrically connected to the voltage end of the signal processing circuit (10), the signal driving circuit (20), and the signal output circuit (30); The voltage regulating circuit (50) is used to adjust the DC voltage to an emission voltage required for object detection, and provide the voltage to the signal processing circuit (10), the signal driving circuit (20), and the signal output circuit (30).

5. The signal transmitting circuit according to claim 3, wherein: The filter circuit (102) includes a capacitor C4 and a resistor R8 connected in parallel; and / or, The signal generating circuit (101) comprises a common-emitter amplifier circuit (1011) and an LC oscillation circuit (1012).

6. The signal transmitting circuit according to claim 5, characterized in that: The common-emitter amplifier circuit (1011) includes a transistor Q3, and the LC oscillation circuit (1012) includes a capacitor C5 and a coil L1 connected in parallel; One end of the LC oscillation circuit (1012) is electrically connected to the collector of the transistor Q3, the base of the transistor Q3 is used to access the initial signal, and the emitter of the transistor Q3 is used to be grounded.

7. The signal transmitting circuit according to any one of claims 1, 2, 3 and 6, characterized in that: The signal driving circuit (20) comprises a complementary symmetrical power amplifier circuit (201); the complementary symmetrical power amplifier circuit (201) comprises: a transistor Q5 and a transistor Q6; The base of the transistor Q5 is electrically connected to the signal processing circuit (10), and the emitter of the transistor Q5 is electrically connected to the signal output circuit (30); the emitter of the transistor Q6 is electrically connected to the signal output circuit (30), and the base of the transistor Q6 is electrically connected to the signal processing circuit (10).

8. The signal transmitting circuit according to any one of claims 1, 2, 3 and 6, characterized in that: The signal output circuit (30) further includes: an alligator clip connected in parallel with the magnetic core coil L2.

9. The signal transmitting circuit according to claim 4, characterized in that: The voltage regulating circuit (50) comprises: Transistor Q1, transistor Q2, resistor R1, Zener diode DZ1, resistor R2 and variable resistor RP1; Wherein, one end of the resistor R1 is electrically connected to the collector of the transistor Q1 and is used to access the DC voltage, and the other end of the resistor R1 is electrically connected to the collector of the transistor Q2 and the base of the transistor Q1; the emitter of the transistor Q1 is electrically connected to one end of the resistor R2, the first end of the variable resistor RP1, and the first voltage end of the signal processing circuit (10), the signal driving circuit (20), and the signal output circuit (30); the base of the transistor Q2 is electrically connected to the adjustment end of the variable resistor RP1, and the emitter of the transistor Q2 is electrically connected to the negative electrode of the voltage-stabilizing diode DZ1 and the other end of the resistor R2; the positive electrode of the voltage-stabilizing diode DZ1 is electrically connected to the second end of the variable resistor RP1 and the second voltage end of the signal processing circuit (10), the signal driving circuit (20), and the signal output circuit (30); Furthermore, the voltage regulating circuit (50) further comprises a resistor R15, one end of the resistor R15 being electrically connected to the base of the transistor Q1, and the other end of the resistor R15 being electrically connected to the other end of the resistor R1 and the collector of the transistor Q2.

10. The signal transmitting circuit according to claim 6, wherein: The output waveform adjustment circuit (40) includes: a resistor R17, a resistor R18 and a capacitor C11; One end of the resistor R17 is electrically connected to the collector of the transistor Q3, and the other end of the resistor R17 is electrically connected to one end of the resistor R18 and one end of the capacitor C11 respectively; the other end of the capacitor C11 is electrically connected to the signal input end of the signal amplifying circuit (103); and the other end of the resistor R18 is used for grounding.

11. The signal transmitting circuit according to claim 10, wherein: The output waveform adjustment circuit (40) further includes: a resistor R16, one end of the resistor R16 being electrically connected to the emitter of the transistor Q3, and the other end of the resistor R16 being grounded; or, a capacitor C6, one end of the capacitor C6 being grounded, and the other end of the capacitor C6 being electrically connected to the emitter of the transistor Q3; or; A resistor R16 and a capacitor C6, one end of the resistor R16 is electrically connected to the emitter of the transistor Q3, one end of the capacitor C6 is grounded, and the other end of the capacitor C6 is electrically connected to the other end of the resistor R16.

12. A cable detector, characterized in that: The cable detector includes a device body and a signal transmitting circuit according to any one of claims 1 to 11.

13. A waveform adjustment method, characterized in that: The method is applied to a signal transmitter, wherein the signal transmitter includes the signal transmission circuit according to any one of claims 1 to 11, and the method includes: Step 1: amplifying and converting the initial signal output by the external device through the signal processing circuit (10) to obtain an oscillation signal; Step 2: power-amplifying the oscillation signal through the signal driving circuit (20) to obtain a power-amplified signal; Step 3: Output the power amplified signal to the detected cable through a wire connected in parallel with the magnetic core coil L2 to obtain a signal on the detected cable; If the waveform of the signal on the detected cable does not meet the preset waveform condition, the parameters of the target device in the signal processing circuit (10) and / or the output waveform adjustment circuit (40) are adjusted, and steps 1, 2, and 3 are re-executed until the waveform of the signal on the detected cable meets the preset waveform condition.

14. The waveform adjustment method according to claim 13, characterized in that: The waveform of the signal on the detected cable satisfies the preset waveform condition, which includes that an amplitude difference between the waveform of the signal on the detected cable and the waveform of the power amplified signal output to the detected cable is within a preset amplitude range.

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