Signal transmitting circuit applied to cable detector and cable detector

Abstract

The utility model relates to cable detection technical field discloses a signal transmitting circuit and cable detector for cable detector, this signal transmitting circuit can include signal processing circuit, signal drive circuit and signal output circuit, and signal output circuit includes magnetic core coil L2, signal processing circuit is used to carry out conversion processing to the initial signal of external device output, generates oscillation signal, oscillation signal transmission reaches magnetic core coil L2 through signal drive circuit, when being detected cable passes through magnetic core coil L2, and magnetic core coil L2 will oscillation signal load to the cable of being detected. Visible, the utility model can pass through signal output circuit and transmit the detection signal to the cable of being detected, be favorable to improve the signal transmission efficiency and signal transmission reliability between cable detector and the cable of being detected.

Description

Technical Field

[0001] This utility model relates to the field of cable detection technology, and in particular to a signal transmitting circuit and a cable detector. Background Technology

[0002] In some applications, it is often necessary to use detection devices to detect objects / items. When a relevant object / item is detected, the detection device will issue a prompt to remind the relevant operators. Currently, one of the more common detection devices is the cable detector, which is mainly used to detect the status of cables laid in walls, underground, ceilings, and other similar locations, such as detecting cable routes and whether there are any breaks in the cables.

[0003] For cable detectors, signals are usually transmitted using alligator clips. This method requires the alligator clips to hold the cable being detected, and the contact points between the alligator clips and the cable being detected have high requirements. If the contact points are oxidized or have oil stains, the contact between the alligator clips and the cable being detected will be unstable, which will affect the signal transmission efficiency and signal transmission reliability.

[0004] Therefore, improving signal transmission efficiency and reliability is particularly important when implementing cable detection. Utility Model Content

[0005] This invention provides a signal transmitting circuit and a cable detector for use in cable detectors, which can improve the signal transmission efficiency and reliability between the cable detector and the cable being detected.

[0006] To solve the above-mentioned technical problems, the first aspect of this utility model discloses a signal transmitting circuit applied to a cable detector, the signal transmitting circuit comprising:

[0007] The system includes a signal processing circuit, a signal driving circuit, and a signal output circuit. The signal input terminal of the signal processing circuit is used to receive the initial signal output by an external device, and the signal output terminal of the signal processing circuit is electrically connected to the signal input terminal of the signal driving circuit. The signal output terminal of the signal driving circuit is electrically connected to the signal output circuit.

[0008] 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 apply the oscillation signal to the cable being probed when the cable being probed passes through the magnetic core coil L2.

[0009] As an optional implementation, in the first aspect of this utility model, the signal processing circuit includes a signal generation circuit, or the signal processing circuit includes a signal generation circuit and a filter circuit electrically connected to the signal generation circuit.

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

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

[0012] A signal amplification circuit, wherein the signal input terminal of the signal amplification circuit is electrically connected to the signal generation circuit, and the signal output terminal of the signal amplification circuit is electrically connected to the signal driving circuit;

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

[0014] As an optional implementation, in the first aspect of this utility model, the signal transmitting circuit further includes:

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

[0016] The voltage regulation 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 implementation, in the first aspect of this utility model, the filter circuit includes a capacitor C4 and a resistor R8 connected in parallel;

[0018] And / or,

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

[0020] As an optional implementation, in the first aspect of this utility model, the common-emitter amplifier circuit includes a transistor Q3, and the LC oscillation circuit includes a capacitor C5 and a coil L1 connected in parallel.

[0021] In this circuit, 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 receive the initial signal, and the emitter of the transistor Q3 is used to ground.

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

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

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

[0025] As an optional implementation, in the first aspect of this invention, the voltage regulation circuit includes:

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

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

[0028] The second aspect of this utility model discloses a cable detector, which includes a device body and a signal transmitting circuit for use in the cable detector as described in any one of the first aspects of this utility model.

[0029] Implementing this utility model has the following beneficial effects:

[0030] The signal transmitting circuit disclosed in this utility model for a cable detector includes a signal processing circuit, a signal driving circuit, and a signal output circuit, wherein 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 the 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 cable to be detected passes through the magnetic core coil L2, the magnetic core coil L2 applies the oscillation signal to the cable to be detected. Therefore, this utility model can transmit the detection signal to the cable to be detected through the magnetic core coil. Compared with the alligator clip method, this not only improves the signal transmission efficiency, reliability, and stability between the cable detector and the cable to be detected, but also eliminates the need to damage the cable's wiring; the cable to be detected only needs to pass through the central hole of the magnetic core coil L2. Furthermore, it can simultaneously detect multiple cables or wire cores, making it applicable to a wider range of scenarios. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the structure of a signal transmitting circuit for a cable detector disclosed in an embodiment of this utility model;

[0033] Figure 2 This is a schematic diagram of another signal transmitting circuit for a cable detector disclosed in this embodiment of the present invention;

[0034] Figure 3 This is a waveform comparison diagram disclosed in an embodiment of the present invention. Detailed Implementation

[0035] To better understand and implement this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0036] It should be noted that, unless otherwise explicitly specified and limited, the term "electrical connection" in the specification, claims, and accompanying drawings of this utility model should be interpreted broadly. For example, it can refer to a fixed electrical connection, a detachable electrical connection, or an integral electrical connection; it can refer to a mechanical electrical connection or a mutually communicating connection; it can refer to a direct connection or an indirect connection through an intermediate medium; it can refer to the internal connection of two components or the interaction between two components. Furthermore, the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish different objects, not to describe a specific order. The terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0037] This utility model discloses a signal transmitting circuit and a cable detector for use in cable detectors. It can transmit detection signals to the cable being detected via a magnetic core coil. Compared to alligator clips, this not only improves the signal transmission efficiency, reliability, and stability between the cable detector and the cable being detected, but also eliminates the need to damage the cable's wiring; the cable simply needs to pass through the central hole of the magnetic core coil L2. Furthermore, it can simultaneously detect multiple cables or wire cores, making it applicable to a wider range of scenarios. Detailed descriptions follow.

[0038] Example 1

[0039] Please see Figure 1 , Figure 1 This is a schematic diagram of a signal transmitting circuit used in a cable detector, as disclosed in an embodiment of this utility model. Specifically, this signal transmitting circuit is used in the signal transmitter of the cable detector to realize signal transmission between the cable detector and the cable being detected, thereby enabling the detection of the cable. Figure 1 As shown, the signal transmitting circuit may include:

[0040] The circuit includes a signal processing circuit 10, a signal driving circuit 20, and a signal output circuit 30. The signal input terminal of the signal processing circuit 10 is used to receive the initial signal output by an external device, and the signal output terminal of the signal processing circuit 10 is electrically connected to the signal input terminal of the signal driving circuit 20. The signal output terminal of the signal driving circuit 20 is electrically connected to the signal output circuit 30. 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 (not shown in the figure) connected in parallel with the magnetic core coil L2.

[0041] In this 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 via the signal driving circuit 20; the magnetic core coil L2 is used to load the oscillation signal onto the probed cable when the probed cable passes through the magnetic core coil L2.

[0042] In this embodiment of the invention, the initial signal output by the external device (also known as the "signal generator") can also be understood as a detection trigger signal, and the initial signal can be specifically generated by the microcontroller controlling the external device 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 application scenarios. This embodiment of the invention does not limit this. Furthermore, the initial signal can be a square wave signal or a sine wave signal.

[0043] As can be seen, this embodiment of the invention can transmit the detection signal to the cable being detected through the magnetic core coil. Compared with the alligator clip method, it not only improves the signal transmission efficiency, reliability, and stability between the cable detector and the cable being detected, but also eliminates the need to damage the cable's wiring. The cable to be detected simply needs to pass through the central hole of the magnetic core coil L2. Furthermore, it can simultaneously detect multiple cables or wire cores, making it applicable to a wider range of scenarios. In addition to the magnetic core coil L2, the signal output circuit 30 can further include an alligator clip, giving the signal transmission circuit at least two signal transmission methods, which improves signal transmission flexibility and thus enhances cable detection flexibility.

[0044] In an optional embodiment, the signal processing circuit 10 may include a signal generation circuit 101, and further may include a filter circuit 102 electrically connected to the signal generation circuit 101.

[0045] The signal generation circuit 101 is used to convert the initial signal to obtain the converted signal, and to amplify the converted signal by frequency selection 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 cable being probed.

[0046] In this embodiment of the invention, optionally, the initial signal output by the external device is a square wave signal. Specifically, the signal generation circuit 101 converts the square wave signal output by the external device into an analog sine wave signal and performs frequency-selective amplification to generate an oscillation signal within a certain oscillation frequency range. Further optionally, the filter circuit 102 is used to perform signal filtering to reduce signal interference and improve signal quality.

[0047] As can be seen, this optional utility model embodiment can also selectively amplify signals of a specific frequency, enhance useful signals, suppress interference signals, and thus improve signal quality.

[0048] In another alternative embodiment, such as Figure 2 As shown, the signal processing circuit 10 described above may further include a signal amplification circuit 103 (also referred to as a push-pull preamplifier circuit). The signal input terminal of the signal amplification circuit 103 is electrically connected to the signal generation circuit 101, and the signal output terminal of the signal amplification circuit 103 is electrically connected to the signal driving circuit 20. The signal amplification circuit 103 amplifies the oscillation signal and transmits the amplified oscillation signal to the signal driving circuit 20. Optionally, the signal amplification circuit 103 and the signal generation circuit 101 can be connected via... Figure 2 The coupling capacitor C7 shown in the diagram not only ensures stable signal transmission but also filters out noise signals and reduces interference.

[0049] In this optional embodiment, further optional, such as Figure 2 As shown, the signal amplification circuit 103 may include a transistor Q4; wherein the base of the transistor Q4 is electrically connected to the signal generation 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 amplification circuit 103 may further include other electronic components to assist in achieving the signal amplification function; please refer to [link to relevant documentation] for details. Figure 2 The resistors R10 and R11 shown in the figure can set a suitable static operating point for the transistor Q4, so that the transistor Q4 operates in a suitable amplification region, further improving the signal amplitude and preparing for subsequent power amplification.

[0050] As can be seen, the signal processing circuit 10 in this optional embodiment can enhance the signal driving capability through the signal amplification circuit 103, which is beneficial to improving the reliability of signal transmission. In addition, the signal amplification is achieved through transistors, which simplifies the structure, reduces the complexity of the signal transmission circuit, and saves costs.

[0051] In yet another alternative embodiment, such as Figure 2 As shown, the signal transmitting circuit may further include:

[0052] The voltage regulation circuit 40 has a signal input terminal for receiving DC voltage and a signal output terminal electrically connected to the voltage terminals of the signal processing circuit 10, the signal driving circuit 20, and the signal output circuit 30. The voltage regulation circuit 40 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.

[0053] In this optional embodiment, further optional, such as Figure 2 As shown, the voltage regulation circuit 40 may include:

[0054] Transistor Q1, transistor Q2, resistor R1, Zener diode DZ1, resistor R2, and variable resistor RP1;

[0055] In this circuit, one end of resistor R1 is electrically connected to the collector of transistor Q1 and is used to apply a DC voltage; the other end of resistor R1 is electrically connected to the collector of transistor Q2 and the base of transistor Q1. The emitter of transistor Q1 is electrically connected to one end of resistor R2, the first end of variable resistor RP1, and the first voltage terminal of signal processing circuit 10, signal driving circuit 20, and signal output circuit 30. The base of transistor Q2 is electrically connected to the adjustment terminal of variable resistor RP1, and the emitter of transistor Q2 is electrically connected to the negative terminal of Zener diode DZ1 and the other end of resistor R2. The positive terminal of Zener diode DZ1 is electrically connected to the second end of variable resistor RP1 and the second voltage terminal of signal processing circuit 10, signal driving circuit 20, and signal output circuit 30.

[0056] In this optional embodiment, transistors Q1 and Q2 form a composite transistor, which serves to adjust the output voltage; resistor R1 provides bias current for transistor Q1; Zener diode DZ1 provides a stable reference voltage for the base of transistor Q2; resistor RP1 is a variable resistor whose resistance value can be adjusted. By adjusting the resistance value of variable resistor RP1, the potential of the base of transistor Q can be changed, thereby adjusting the output voltage and realizing the voltage regulation function of the entire circuit.

[0057] In this optional embodiment, further optional options include, for example... Figure 2As shown, the voltage regulation circuit 50 also 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. The resistor R15 primarily limits the base current of the transistor Q2. By setting an appropriate value for the resistor R15, it is possible to ensure that the transistor Q2 operates in a suitable bias state, reducing the possibility of the transistor Q2 failing to perform its amplification function due to excessive or insufficient base current, thus affecting the overall circuit operation. Furthermore, adding resistor R15 can also reduce the standby power consumption of the signal transmission circuit.

[0058] As can be seen, this optional embodiment can not only provide a stable transmission voltage through the voltage regulation circuit 40, but also adjust the transmission voltage through the variable resistor RP1, which is beneficial to improving the flexibility and convenience of signal strength adjustment. In addition, it can ensure that the transistor Q2 operates in a suitable bias state, reducing the occurrence of situations where the transistor Q2 cannot perform amplification and other functions properly due to excessive or insufficient base current, thus affecting the working state of the entire circuit. It can also reduce the standby power consumption of the signal transmission circuit.

[0059] In yet another alternative embodiment, such as Figure 2 As shown, the signal generation circuit 101 includes a common-emitter amplifier circuit 1011 and an LC oscillator circuit 1012.

[0060] In this optional embodiment, the common-emitter amplifier circuit 1011 further optionally includes a transistor Q3, and the LC oscillation circuit 1012 includes a capacitor C5 and an inductor L1 connected in parallel; wherein, 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 receive the initial signal, and the emitter of the transistor Q3 is grounded. Optionally, the initial signal can be transmitted through... Figure 2 The coupling capacitor C3 shown is input to the base of transistor Q3.

[0061] Further optionally, the common-emitter amplifier circuit 1011 may further include a voltage divider circuit formed by resistors R5 and R6 connected in series to provide a suitable bias voltage for transistor Q3. This voltage divider circuit provides a stable base bias voltage to transistor Q3, enabling conduction control between the collector and emitter of transistor Q3, thereby facilitating the generation and control of the oscillation signal. Further optionally, such as... Figure 2 As shown, the common-emitter amplifier circuit 1011 may further include a negative feedback circuit composed of resistor R7 and capacitor C6 to stabilize the operating point of transistor Q3 and improve the performance of the common-emitter amplifier circuit 1011.

[0062] As can be seen, this optional embodiment can realize both switching and signal amplification functions through transistor Q3, thereby flexibly controlling the generation of oscillation signals. Furthermore, the oscillation circuit (also known as a resonant circuit) formed by capacitor C5 and coil L1 in parallel achieves frequency selection of a specific frequency signal, and transistor Q3 amplifies the signal at that specific frequency, enhancing the useful signal and suppressing interference signals, which is beneficial for improving the stability and reliability of signal transmission.

[0063] In yet another alternative embodiment, such as Figure 2 As shown, the filter circuit 102 described above may include a capacitor C4 and a resistor R8 connected in parallel. It is evident that this optional embodiment can filter out interference signals through the filter circuit 102, and its structure is simple.

[0064] In yet another alternative embodiment, such as Figure 2 As shown, the signal driving circuit 20 described above includes a complementary symmetry power amplifier circuit 201. Optionally, the complementary symmetry power amplifier circuit 201 may include transistors Q5 and Q6; the base of transistor Q5 is electrically connected to the signal processing circuit 10, and the emitter of transistor Q5 is electrically connected to the signal output circuit 30; the emitter of transistor Q6 is electrically connected to the signal output circuit 30, and the base of transistor Q6 is electrically connected to the signal processing circuit 10. Further optionally, the signal driving circuit 20 may also include a bias voltage providing circuit 202.

[0065] The first terminal of the bias voltage providing circuit 202 is electrically connected to the base of transistor Q5, and the second terminal of the bias voltage providing circuit is electrically connected to the base of transistor Q6 and the signal output terminal (i.e., the collector of transistor Q4) of the signal processing circuit 10.

[0066] Further optional, such as Figure 2 As shown, the bias voltage providing circuit 202 may include diodes VD1 and VD2 connected in series. The anode of diode VD1 serves as the first terminal of the bias voltage providing circuit 202, and the cathode of diode VD2 serves as the second terminal of the bias voltage providing circuit 202. The bias voltage providing circuit 202, composed of diodes VD1 and VD2, can provide bias voltages to transistors Q5 and Q6, thereby driving transistors Q5 and Q6 to conduct within their respective signal cycles.

[0067] In this optional embodiment, transistor Q5 is further optionally an NPN transistor, and transistor Q6 is a PNP transistor, with transistors Q5 and Q6 forming a complementary symmetrical power amplifier circuit. During the positive half-cycle of the oscillation signal, the base potential of transistor Q5 rises, and after meeting the conduction condition, transistor Q5 begins to conduct. At this time, transistor Q5 amplifies 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 operate. When the negative half-cycle of the oscillation signal arrives, the base potential of transistor Q6 decreases, and after meeting the conduction condition, it conducts. It amplifies the signal during the negative half-cycle, obtains reverse current from the circuit, and outputs it to the magnetic core coil L2 through capacitor C9, continuing to drive the load. In other words, transistors Q5 and Q6 work in a complementary manner, cooperating with each other to alternately conduct within a complete signal cycle, providing continuous drive current to the magnetic core coil L2, reducing signal distortion and ensuring that the magnetic core coil L2 can accurately reproduce the input signal.

[0068] As can be seen, this optional embodiment can not only amplify the signal through transistors Q5 and Q6 in the signal driving circuit 20, but also alternately conduct to provide a continuous driving current to the magnetic core coil L2 within a complete signal cycle, reducing signal distortion and ensuring that the magnetic core coil L2 can accurately reproduce the input signal.

[0069] In yet another alternative embodiment, such as Figure 2As shown, the signal transmitting circuit may further include an output waveform adjustment circuit 50. The output waveform adjustment circuit 50 is electrically connected to the signal processing circuit 10 and is used to adjust the waveform of the oscillation signal so that after the oscillation signal is applied to the probed cable, the waveform of the signal on the probed cable meets a preset waveform condition. Further optionally, meeting the preset waveform condition may include: the amplitude difference between the waveform of the signal on the probed cable and the waveform of the oscillation signal output to the probed cable is within a preset amplitude range. Existing signal transmitters, after transmitting signals to the cable being probed, suffer from waveform distortion due to interference from the cable. This waveform distortion alters the phase, amplitude, or frequency characteristics of the signal received by the cable detector's receiver, leading to confusion between signals from different cables in complex pipeline environments (such as multiple cables crossing or running parallel). Consequently, the signal receiver struggles to identify the corresponding cable. Furthermore, waveform distortion is 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. In other words, existing signal transmitters suffer from poor cable detection performance due to waveform distortion of the signal transmitted to the cable being probed. However, this invention incorporates an output waveform adjustment circuit 50 in the signal transmitter's transmission circuit to adjust the waveform of the oscillating signal applied to the cable being probed. This reduces waveform distortion caused by interference from the cable being probed, thereby improving cable detection performance, such as increasing detection accuracy and effectively extending the detection distance.

[0070] In this optional embodiment, further optional, such as Figure 2 As shown, the output waveform adjustment circuit 50 described above may include: resistor R17, resistor R18, and capacitor C11. One end of resistor R17 is electrically connected to the collector of transistor Q3, and the other end of resistor R17 is electrically connected to one end of resistor R18 and one end of capacitor C11. The other end of capacitor C11 is electrically connected to the signal input terminal of signal amplifier circuit 103. The other end of resistor R18 is used for grounding.

[0071] In this optional embodiment, resistor R17 serves to limit current and match impedance in the signal transmission path, preventing damage to subsequent circuits due to excessive current during signal transmission, and ensuring proper impedance matching between the signal source and the load, reducing signal reflection. Resistor R18, in conjunction with transistor Q4, sets the base bias voltage of transistor Q4, determining its quiescent operating point and ensuring that transistor Q4 can properly amplify the input signal. Capacitor C11 is a coupling capacitor, its function being to isolate DC signals, allowing only AC signals to pass through, transmitting the AC signal from the preceding circuit (such as the signal processed by components like resistor R17) to the base of transistor Q4, while preventing the DC operating points of the preceding and following circuits from interfering with each other.

[0072] Further options include, such as Figure 2 As shown, the output waveform adjustment circuit 50 described above may further include:

[0073] Resistor R16, one end of resistor R16 is electrically connected to the emitter of transistor Q3, and the other end of resistor R16 is used for grounding;

[0074] or,

[0075] Capacitor C6, one end of capacitor C6 is used for grounding, and the other end of capacitor C6 is electrically connected to the emitter of transistor Q3;

[0076] or;

[0077] The resistor R16 and capacitor C6 are connected together. 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.

[0078] In this optional embodiment, resistor R16, in the collector circuit of transistor Q3, serves to convert the change in collector current of transistor Q3 into a voltage change, so that the amplified signal can be transmitted to subsequent circuits. It also affects the operating point of transistor Q3. Capacitor C6 is a bypass capacitor, which is equivalent to a short circuit for AC signals. It allows the AC signal at 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 subsequent circuits without attenuation.

[0079] It should be noted that some or all of the components in the output waveform adjustment circuit 50 can be components with fixed parameters or components with variable parameters.

[0080] In this optional embodiment, the waveform of the output signal can be shaped and adjusted by the parameters of the relevant components in the output waveform adjustment circuit 50, so as to improve the signal quality on the probed cable after the oscillation signal is applied to the probed cable. The waveform adjustment method is convenient and low in cost.

[0081] In another alternative embodiment, adjusting the signal waveform output by the signal transmitting circuit can also be achieved by changing the resistance value of resistor R11 and / or the capacitance value of capacitor C10 in the signal amplification circuit 103.

[0082] Increasing the value of resistor R11 enhances the AC negative feedback at the emitter of transistor Q4. When detecting cables, the increased signal amplitude introduced by multi-core cables can be mitigated by the enhanced AC negative feedback, which reduces the amplification factor of transistor Q4, thus lowering the output signal amplitude and alleviating amplitude anomalies. Furthermore, the nonlinear distortion caused by the detected cable can be corrected by improving the linearity of transistor Q4. Conversely, decreasing the value of resistor R11 weakens the AC negative feedback at the emitter of transistor Q4, increasing its amplification factor. Therefore, when detecting cables, if multi-core cables cause signal amplitude attenuation, appropriately reducing the value of resistor R11 can improve the signal amplitude.

[0083] In this optional embodiment, when adjusting the capacitance value of capacitor C10, increasing the capacitance value of capacitor C10 reduces its capacitive reactance in the low-frequency range, thus weakening the AC negative feedback effect of resistor R11 in the low-frequency range. In actual cable detection, if multi-core cables attenuate the low-frequency components of the signal, increasing the capacitance value of capacitor C10 can relatively increase the low-frequency amplitude of the output signal, compensating for low-frequency losses and thereby improving signal quality.

[0084] It should be noted that in this optional embodiment, the signal transmitting circuit may not include the output waveform adjustment circuit 50. When it is necessary to adjust the signal waveform, it can be achieved directly by changing the resistance value of resistor R11 and / or the capacitance value of capacitor C10 in the signal amplification circuit 103.

[0085] As can be seen, this optional embodiment can adjust the signal waveform by changing the resistance value of resistor R11 and / or the capacitance value of capacitor C10 in the signal amplification circuit 103, which is beneficial to improving signal quality. Moreover, the waveform adjustment method is relatively convenient and low in cost.

[0086] For example, waveform comparisons when adjusting device parameters to achieve waveform adjustment can be referenced. Figure 3 As shown. Among them, Figure 3 The 3A in the diagram represents the signal waveform output by the signal transmitting circuit under no-load conditions after adjusting the device parameters. Figure 3Figure 3-B shows the signal waveform on the probed cable after the signal output from the signal transmitting circuit is applied to the probed cable following the adjustment of the device parameters. As can be seen from the waveform shown in 3-B, the main difference from the waveform shown in 3-A is that the waveform becomes smoother after connecting the probed cable during the waveform drop. In other words, connecting the probed cable makes the waveform smoother and eliminates noise, which improves the signal quality on the probed cable after the signal is applied, thus improving the cable detection effect.

[0087] Example 2

[0088] This utility model discloses a cable detector, which includes a device body and any of the signal transmitting circuits described in Embodiment 1.

[0089] The above provides a detailed description of a signal transmitting circuit and a cable detector used in a cable detector, as disclosed in the embodiments of this utility model. Specific embodiments have been used to illustrate the principles and implementation methods of this utility model. However, the above preferred embodiments are not intended to limit this utility model. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this utility model. Furthermore, for those skilled in the art, based on the ideas of this utility model, changes may be made in the specific implementation methods and application scope without departing from the spirit and scope of this utility model. Therefore, the protection scope of this utility model is determined by the scope defined in the claims.

Claims

1. A signal transmitting circuit for use in a cable detector, characterized in that, The signal transmitting circuit includes: The signal processing circuit (10), the signal driving circuit (20), and the signal output circuit (30) are provided. The signal input terminal of the signal processing circuit (10) is used to receive the initial signal output by an external device. The signal output terminal of the signal processing circuit (10) is electrically connected to the signal input terminal of the signal driving circuit (20). The signal output terminal of the signal driving circuit (20) is electrically connected to the signal output circuit (30). 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 probed cable when the probed cable passes through the magnetic core coil L2.

2. The signal transmitting circuit for a cable detector according to claim 1, characterized in that, The signal processing circuit (10) includes a signal generation circuit (101), or the signal processing circuit (10) includes a signal generation circuit (101) and a filter circuit (102) electrically connected to the signal generation circuit (101). The signal generation circuit (101) is used to perform signal conversion on the initial signal to obtain the converted signal, and to perform frequency selective amplification on the converted signal to generate an oscillation signal.

3. The signal transmitting circuit for a cable detector according to claim 2, characterized in that, The signal processing circuit (10) further includes: The signal amplification circuit (103) is electrically connected to the signal generation circuit (101) at its signal input terminal and electrically connected to the signal driving circuit (20) at its signal output terminal. The signal amplification 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 for a cable detector according to any one of claims 1-3, characterized in that, The signal transmitting circuit also includes: A voltage regulation circuit (40) is provided, wherein the signal input terminal of the voltage regulation circuit (40) is used to connect to a DC voltage, and the signal output terminal of the voltage regulation circuit (40) is electrically connected to the voltage terminals of the signal processing circuit (10), the signal driving circuit (20), and the signal output circuit (30). The voltage regulation circuit (40) 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).

5. The signal transmitting circuit for a cable detector according to claim 2 or 3, characterized in that, The filter circuit (102) includes a capacitor C4 and a resistor R8 connected in parallel; And / or, The signal generation circuit (101) includes a common-emitter amplifier circuit (1011) and an LC oscillator circuit (1012).

6. The signal transmitting circuit for a cable detector 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. In this circuit, 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 receive the initial signal, and the emitter of the transistor Q3 is used to ground.

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

8. The signal transmitting circuit for a cable detector 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 for a cable detector according to claim 4, characterized in that, The voltage regulation circuit (40) includes: 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 connect to 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 terminal 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 terminal of the variable resistor RP1, and the emitter of the transistor Q2 is electrically connected to the negative terminal of the Zener diode DZ1 and the other end of the resistor R2; the positive terminal of the Zener diode DZ1 is electrically connected to the second end of the variable resistor RP1 and the second voltage terminal of the signal processing circuit (10), the signal driving circuit (20), and the signal output circuit (30); In addition, the voltage regulation circuit (40) 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.

10. A cable detector, characterized in that, The cable detector includes a device body and a signal transmitting circuit applied to the cable detector as described in any one of claims 1-9.

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