Anti-saturation signal transmission circuit
By designing an anti-saturation signal transmission circuit in a wireless microphone, and utilizing coupling circuits, overload detection modules, and bypass attenuation circuits, the problems of signal distortion and circuit damage caused by receiver overload are solved, achieving effective signal attenuation and improved receiver reliability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- GUANGZHOU BAOLUN ELECTRONICS CO LTD
- Filing Date
- 2025-08-05
- Publication Date
- 2026-07-24
AI Technical Summary
In wireless microphones, when the transmitter and receiver are very close together, the receiver is prone to signal overload, which can lead to signal distortion or damage to circuit components, affecting normal use.
An anti-saturation signal transmission circuit was designed, including a coupling circuit, an overload detection module, a switching module, and a bypass attenuation circuit. When the overload detection module detects a power overload, it controls the switching module to conduct the bypass attenuation circuit to attenuate the signal, thereby avoiding signal distortion and circuit damage.
It achieves effective signal attenuation under overload conditions, preventing signal distortion and damage to circuit components, extending the receiver's lifespan and improving reliability.
Smart Images
Figure CN224555770U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of microphone technology, and more specifically, to an anti-saturation signal transmission circuit. Background Technology
[0002] In the field of wireless microphones, to ensure that the receiver can effectively receive the antenna signal transmitted by the transmitter even when the receiver is far away from the transmitter, a high-sensitivity signal transmission circuit is often used to process the received antenna signal. However, when the transmitter and receiver are very close (e.g., within 1 meter), the receiver will receive a relatively strong antenna signal (i.e., power overload). If the signal transmission circuit is used, it will enter the nonlinear amplification region, causing signal distortion and making it impossible to demodulate the antenna signal; or the excessive gain of the device may damage some components in the receiver's signal link, affecting the normal operation of the receiver. Utility Model Content
[0003] This application provides an anti-saturation signal transmission circuit that can solve the problem that existing transmitters and receivers cannot demodulate signals or damage circuit components when they are very close, thus affecting the use of the receiver.
[0004] To achieve this objective, the embodiments of this application provide the following solutions.
[0005] According to one aspect of the embodiments of this application, an anti-saturation signal transmission circuit is provided, including a coupling circuit, an overload detection module, a switching module, and a signal transmission module provided with a bypass attenuation circuit. The input terminal of the coupling circuit receives an antenna signal, the output terminal is connected to the signal transmission module, the coupling terminal is connected to the detection terminal of the overload detection module, and the bypass attenuation circuit is provided with an attenuator.
[0006] The overload detection module is used to output an overload signal to the switching module when a power overload is detected at the coupling terminal;
[0007] The switching module is used to control the bypass attenuation circuit to turn on when the overload signal is detected, so that the bypass attenuation circuit transmits the signal output by the coupling circuit.
[0008] In one possible implementation, the coupling circuit includes a directional coupler, a sixth capacitor, a seventh capacitor, and a fourteenth resistor. The first end of the seventh capacitor is connected to the antenna, and the other end is connected to the signal output terminal of the directional coupler. The coupling terminal of the directional coupler is connected to the overload detection module. The first end of the fourteenth resistor is connected to the impedance matching pin of the directional coupler, and the second end is grounded. The output terminal of the directional coupler is connected to the signal transmission module.
[0009] In one possible implementation, the overload detection module includes a detector circuit and a comparator circuit. The detection terminal of the detector circuit is connected to the coupling circuit, the output terminal of the detector circuit is connected to the input terminal of the comparator circuit, and the output terminal of the comparator circuit is connected to the switching module.
[0010] In one possible implementation, the detection circuit includes a detector, a first resistor, a fourth resistor, a third capacitor, an eighth resistor, and a fifth capacitor. A first terminal of the first resistor is connected to a first terminal of the fourth resistor and a coupling terminal of the coupling circuit. A second terminal of the first resistor is connected to a first reference voltage source and a voltage terminal of the detector. A second terminal of the fourth resistor is connected to a first terminal of the third capacitor. A second terminal of the third capacitor is connected to the RF input terminal of the detector. The enable pin of the detector is connected to a first terminal of the eighth resistor, a first terminal of the fifth capacitor, and the first reference voltage source. The second terminals of the eighth resistor and the fifth capacitor are grounded. The output terminal of the detector is connected to the comparator circuit.
[0011] In one possible implementation, the comparator circuit includes a comparator, a sixth resistor, a seventh resistor, a tenth resistor, and a ninth resistor. The overload signal is low. The inverting input of the comparator is connected to the output of the detector circuit. The first terminal of the sixth resistor is connected to a second reference voltage source, and the second terminal is connected to the second terminal of the sixth resistor, the first terminal of the ninth resistor, and the first terminal of the seventh resistor. The second terminal of the seventh resistor is connected to the non-inverting input of the comparator and the first terminal of the tenth resistor. The second terminal of the tenth resistor is connected to the output of the comparator.
[0012] In one possible implementation, the signal transmission module further includes a through circuit, and the switching module includes a first transistor, a twentieth resistor, a first switching circuit, and a second switching circuit. The base of the first transistor is connected to the output terminal of the comparator and the control terminal of the first switching circuit. The first switching circuit is connected to the bypass attenuation circuit to control the bypass attenuation circuit to be turned on or off.
[0013] The collector of the first transistor is connected to the control terminal of the second switching circuit and the second terminal of the twentieth resistor. The first terminal of the twentieth resistor is connected to the second reference voltage source, and the emitter is grounded. The second switching circuit is connected to the through circuit to control the through circuit to turn on or off.
[0014] In one possible implementation, both the through circuit and the bypass attenuation circuit include an isolation inductor and an isolation capacitor. One end of the isolation inductor is grounded, and the other end is connected to the first end of the isolation capacitor. The second end of the isolation capacitor is connected to the output terminal of the signal transmission module.
[0015] In one possible implementation, the bypass attenuation circuit is connected in series with a first diode. The first switching circuit includes a third transistor, a twenty-first resistor, a first field-effect transistor, and a thirteenth resistor. The base of the third transistor is connected to the output of the comparator. The emitter of the third transistor is grounded, and its collector is connected to the first terminal of the twenty-first resistor and the gate of the first field-effect transistor. The second terminal of the twenty-first resistor is connected to a first reference voltage source and the source of the first field-effect transistor. The drain of the first field-effect transistor is connected to the first terminal of the thirteenth resistor. The second terminal of the thirteenth resistor is connected to the anode of the first diode, and the cathode of the first diode is electrically connected to the output of the bypass attenuation circuit.
[0016] In one possible implementation, the through circuit includes a second diode, the circuit structure of the second switching circuit is the same as that of the first switching circuit, the output terminal of the second switching circuit is connected to the anode of the second diode, and the cathode of the second diode is electrically connected to the output terminal of the signal transmission module.
[0017] In one possible implementation, the attenuator includes a fifteenth resistor, a sixteenth resistor, and a seventeenth resistor. The second terminal of the fifteenth resistor is grounded, and its first terminal is connected to the output terminal of the coupling circuit and the first terminal of the fifteenth resistor. The second terminal of the fifteenth resistor is connected to the first terminal of the seventeenth resistor and the anode of the first diode. The second terminal of the seventeenth resistor is grounded.
[0018] The beneficial effects of the technical solutions provided in this application are:
[0019] The anti-saturation signal transmission circuit provided in this application includes a coupling circuit, an overload detection module, a switching module, and a signal transmission module equipped with a bypass attenuation circuit. The input terminal of the coupling circuit receives the antenna signal, and the output terminal is connected to the signal transmission module. The coupling terminal is connected to the detection terminal of the overload detection module. The bypass attenuation circuit is equipped with an attenuator. The overload detection module outputs an overload signal to the switching module when it detects a power overload at the coupling terminal. The switching module controls the bypass attenuation circuit to conduct when it detects an overload signal, so that the bypass attenuation circuit transmits the signal output by the coupling circuit. This embodiment of the application can attenuate the signal output by the coupling circuit through the bypass attenuation circuit equipped with an attenuator when an overload signal occurs, thereby achieving overload protection, avoiding signal distortion and damage to circuit components, effectively extending the service life of the receiver and improving its reliability. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments of this application will be briefly introduced below.
[0021] Figure 1 This is a structural diagram of the anti-saturation signal transmission circuit provided in an embodiment of this application;
[0022] Figure 2 This is a partial circuit diagram of an anti-saturation signal transmission circuit provided in an embodiment of this application;
[0023] Figure 3 Another part of the circuit diagram of the anti-saturation signal transmission circuit provided in the embodiments of this application.
[0024] Label Explanation:
[0025] U1, Directional Coupler; C6, Sixth Capacitor; C7, Seventh Capacitor; R14, Fourteenth Resistor; C8, Eighth Capacitor; U3, Detector; R1, First Resistor; R4, Fourth Resistor; C3, Third Capacitor; R8, Eighth Resistor; C5, Fifth Capacitor; R2, Second Resistor; U2, Comparator; R6, Sixth Resistor; R7, Seventh Resistor; R10, Tenth Resistor; R9, Ninth Resistor; R5, Fifth Resistor; C4, Fourth Capacitor; C1, First Capacitor; C2, Second Capacitor; R3, Third Resistor; Q1, First Transistor; R11, Eleventh Resistor; R20, Second... 10. Resistor; L2, second inductor; C9, ninth capacitor; L4, fourth inductor; C10, tenth capacitor; D1, first diode; Q3, third transistor; R21, twenty-first resistor; Q2, first field-effect transistor; R13, thirteenth resistor; L1, first inductor; R12, twelfth resistor; D2, second diode; R19, nineteenth resistor; Q5, fifth transistor; R22, twenty-second resistor; Q4, second field-effect transistor; R19, nineteenth resistor; L3, third inductor; R15, fifteenth resistor; R16, sixteenth resistor; R17, seventeenth resistor. Detailed Implementation
[0026] The embodiments of this application are described below with reference to the accompanying drawings. It should be understood that the embodiments described below with reference to the accompanying drawings are exemplary descriptions for explaining the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions of the embodiments of this application.
[0027] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the terms “comprising” and “including” as used in embodiments of this application mean that the corresponding feature can be implemented as the presented feature, information, data, step, operation, element, and / or component, but do not exclude implementation as other features, information, data, step, operation, element, component, and / or combinations thereof supported by the art. It should be understood that when we say that an element is “connected” or “coupled” to another element, the one element can be directly connected or coupled to the other element, or it can mean that the one element and the other element establish a connection relationship through an intermediate element. Furthermore, “connected” or “coupled” as used herein can include wireless connection or wireless coupling. The term “and / or” as used herein indicates at least one of the items defined by the term; for example, “A and / or B” indicates implementation as “A,” or implementation as “A,” or implementation as “A and B.”
[0028] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.
[0029] The technical solutions of this utility model and their effects are described below through several exemplary embodiments. It should be noted that the following embodiments can be referenced, borrowed from, or combined with each other. Identical terms, similar features, and similar implementation steps in different embodiments will not be repeated.
[0030] The anti-saturation signal transmission circuit provided in this application aims to solve at least one technical problem existing in the prior art.
[0031] This application provides an anti-saturation signal transmission circuit in its embodiments, such as... Figures 1-3 As shown, the signal transmission circuit includes a coupling circuit, an overload detection module, a switching module, and a signal transmission module equipped with a bypass attenuation circuit. The input of the coupling circuit receives the antenna signal, and the output is connected to the signal transmission module. The coupling end is connected to the detection end of the overload detection module. The bypass attenuation circuit is equipped with an attenuator. The overload detection module is used to output an overload signal to the switching module when it detects a power overload at the coupling end. The switching module is used to control the bypass attenuation circuit to conduct when it detects an overload signal so that the bypass attenuation circuit transmits the signal output by the coupling circuit.
[0032] Optionally, the signal transmission circuit can be located in the receiver and connected to the receiver's antenna to transmit the antenna signal to the FPGA, microcontroller, and other devices capable of processing antenna signals for subsequent processing. The antenna signal received by the receiver can be transmitted from a microphone, or sent by a remote control, walkie-talkie, or other device; the specific type of device sending the antenna signal can be determined according to actual needs.
[0033] Optionally, the coupling circuit includes a directional coupler U1, a seventh capacitor C7, and a fourteenth resistor R14. The first end of the seventh capacitor C7 is connected to the antenna, and the other end is connected to the signal output terminal of the directional coupler U1. The coupling terminal of the directional coupler U1 is connected to the overload detection module. The first end of the fourteenth resistor R14 is connected to the impedance matching pin of the directional coupler U1, and the second end is grounded. The output terminal of the directional coupler U1 is connected to the signal transmission module.
[0034] Optionally, the coupling circuit also includes a sixth capacitor C6, the first end of which is connected to the overload detection module, and the second end of which is connected to the coupling end of the directional coupler U1.
[0035] In one embodiment, the directional coupler U1 can be a TCD-20-4+, or an IPP-8063, CS10-04-436 / 13, IPP-3003, or other models. The directional coupler U1 has a coupling port and a first output terminal. It processes the received antenna signal and transmits the processed signal to the next stage circuit. The antenna signal is received from the RF-INPUT port through a seventh capacitor C7. The coupling circuit may also include an eighth capacitor C8, with its first end connected to the signal output terminal of the directional coupler U1 and its second end connected to the input terminal of the signal transmission module.
[0036] Optionally, the overload detection module includes a detector circuit and a comparator circuit. The detection terminal of the detector circuit is connected to the coupling circuit, the output terminal of the detector circuit is connected to the input terminal of the comparator circuit, and the output terminal of the comparator circuit is connected to the switching module. Specifically, the detector circuit detects whether the input power at the coupling terminal is overloaded and outputs a signal based on the detection result. The comparator circuit compares the voltage of this signal with a predetermined voltage and outputs an overload signal based on the comparison result. This allows for rapid detection of whether an input power overload exists through the detector circuit and the comparator circuit.
[0037] Optionally, the detection circuit includes a detector U3, a first resistor R1, a fourth resistor R4, a third capacitor C3, an eighth resistor R8, and a fifth capacitor C5. The first end of the first resistor R1 is connected to the first end of the fourth resistor R4 and the coupling end of the coupling circuit. The second end of the first resistor R1 is connected to the first reference voltage source and the voltage terminal of the detector U3. The second end of the fourth resistor R4 is connected to the first end of the third capacitor C3. The second end of the third capacitor C3 is connected to the RF input terminal of the detector U3. The enable pin of the detector U3 is connected to the first end of the eighth resistor R8, the first end of the fifth capacitor C5, and the first reference voltage source. The second ends of the eighth resistor R8 and the second ends of the fifth capacitor C5 are grounded. The output terminal of the detector U3 is connected to the comparator circuit.
[0038] Optionally, detector U3 outputs different voltage signals when the RF input voltage is different. When detector U3 detects power overload at the coupling end of directional coupler U1, it can output a low voltage (voltage lower than a predetermined voltage value) or a high voltage (voltage higher than a predetermined voltage value) so that the comparator circuit can output an overload signal.
[0039] In one embodiment, the detection circuit may further include a second resistor R2, with a first end connected to the output terminal of the detector U3 and a second end connected to the comparator circuit. The detector U3 may be an LMV228, or any other type of detector U3 capable of outputting an electrical signal indicating a change in the input signal.
[0040] Optionally, the output DC signal of the first reference voltage source powers the detector U3. The magnitude of this DC signal can correspond to the operating voltage of the detector U3. Specifically, the magnitude of this DC signal can be 5V.
[0041] Optionally, the comparator circuit includes comparator U2, a sixth resistor R6, a seventh resistor R7, a tenth resistor R10, and a ninth resistor R9. The overload signal is low level. The inverting input of comparator U2 is connected to the output of the detector circuit. The first end of the sixth resistor R6 is connected to the second reference voltage source, and the second end is connected to the second end of the sixth resistor R6, the first end of the ninth resistor R9, and the first end of the seventh resistor R7. The second end of the seventh resistor R7 is connected to the non-inverting input of comparator U2 and the first end of the tenth resistor R10. The second end of the tenth resistor R10 is connected to the output of comparator U2.
[0042] Optionally, the comparator circuit may also include a fifth resistor R5 and a fourth capacitor C4. The second end of the fifth resistor R5 and the second end of the fourth capacitor C4 are grounded, and the first end of the first resistor R1 is connected to the output terminal of the detector circuit, the first end of the fourth capacitor C4, and the inverting input terminal of the comparator U2.
[0043] In one embodiment, the voltage of the second reference voltage source can be 3.3V. The output terminal of the detector U3 is connected to the inverting input terminal of the comparator U2. The voltage at the inverting input terminal is denoted as U1, and the voltage at the non-inverting input terminal is denoted as U2. At this time, U2 = 3.3V * the resistance value of the sixth resistor R6 / (the resistance value of the sixth resistor R6 + the resistance value of the ninth resistor R9). The voltage of U2 can be adjusted according to the resistance values of the sixth resistor R6 and the ninth resistor R9. U1 and U2 are compared. If the voltage U2 at the non-inverting input terminal is greater than the voltage U1 at the inverting input terminal, the comparator U2 outputs a high voltage of 3.3V. If the voltage U2 at the non-inverting input terminal is less than the voltage U1 at the inverting input terminal, the comparator U2 outputs a low voltage close to 0V.
[0044] Alternatively, the comparator U2 can be an SGM8752, or an LM339, LM393, TLV3011, TS881, or other models.
[0045] In one embodiment, the comparator circuit may further include a first capacitor C1, a second capacitor C2, and a third resistor R3. The second terminals of the first capacitor C1 and the second capacitor C2 are grounded. The first terminals of the first capacitor C1 and the second capacitor C2 are connected to a second reference voltage source and the negative power supply pin of comparator U2. The positive power supply pin of comparator U2 is grounded. The first terminal of the third resistor R3 is connected to the output terminal of comparator U2, and the second terminal is connected to the switching module. Alternatively, the negative power supply pin of comparator U2 can be grounded, and the positive power supply pin can be connected to the first capacitor C1, the second capacitor C2, and the second reference voltage source. The connection method of the positive and negative power supply pins of comparator U2 can be determined according to the model of comparator U2 and its intended function.
[0046] Optionally, the signal transmission module further includes a through circuit, and the switching module includes a first transistor Q1, an eleventh resistor R11, a first switching circuit, and a second switching circuit. The base of the first transistor Q1 is connected to the output terminal of the comparator U2 and the control terminal of the first switching circuit. The first switching circuit is connected to the bypass attenuation circuit to control the bypass attenuation circuit to be turned on or off. The collector of the first transistor Q1 is connected to the second reference voltage source and the control terminal of the second switching circuit, and the emitter is connected to the second terminal of the eleventh resistor R11. The first terminal of the eleventh resistor R11 is grounded. The second switching circuit is connected to the through circuit to control the through circuit to be turned on or off.
[0047] Alternatively, the eleventh resistor R11 can also be connected to the ground terminal of comparator U2. Specifically, when comparator U2 is model SGM8752, it can be connected to the positive power supply pin of comparator U2.
[0048] Optionally, the switching module may also include a twentieth resistor R20, the first end of which is connected to the collector of the first transistor Q1, and the second end of which is connected to the second reference voltage source.
[0049] In one embodiment, the voltage of the second reference voltage source can be 3.3V, and the magnitude of its output voltage can be adjusted according to the operating voltage of comparator U2.
[0050] Optionally, both the through circuit and the bypass attenuation circuit include an isolation inductor and an isolation capacitor. One end of the isolation inductor is grounded, and the other end is connected to the first end of the isolation capacitor. The second end of the isolation capacitor is connected to the output terminal of the signal transmission module.
[0051] In one embodiment, the isolation inductor in the through circuit is the second inductor L2, and the isolation capacitor is the ninth capacitor C9; in the bypass attenuation circuit, the isolation inductor is the fourth inductor L4, and the isolation capacitor is the tenth capacitor C10.
[0052] Optionally, the bypass attenuation circuit is connected in series with a first diode D1. The first switching circuit includes a third transistor Q3, a twenty-first resistor R21, a first field-effect transistor Q2, and a thirteenth resistor R13. The base of the third transistor Q3 is connected to the output terminal of the comparator U2. The emitter of the third transistor Q3 is grounded, and the collector is connected to the first terminal of the twenty-first resistor R21 and the gate of the first field-effect transistor Q2. The second terminal of the twenty-first resistor R21 is connected to the first reference voltage source and the source of the first field-effect transistor Q2. The drain of the first field-effect transistor Q2 is connected to the first terminal of the thirteenth resistor R13. The second terminal of the thirteenth resistor R13 is connected to the anode of the first diode D1. The cathode of the first diode D1 is electrically connected to the output terminal of the bypass attenuation circuit.
[0053] Optionally, the first switching circuit further includes a first inductor L1 and a twelfth resistor R12. The first terminal of the twelfth resistor R12 is connected to the output terminal of comparator U2, and the second terminal is connected to the base of the third transistor Q3. The first terminal of the first inductor L1 is connected to the second terminal of the thirteenth resistor R13, and the second terminal of the first inductor L1 is connected to the anode of the first diode D1. The first inductor L1 and the second inductor L2 form an isolation structure to prevent radio frequency signals from crossing to ground or affecting the power supply.
[0054] Optionally, the through circuit includes a second diode D2. The circuit structure of the second switching circuit is the same as that of the first switching circuit. The output terminal of the second switching circuit is connected to the anode of the second diode D2, and the cathode of the second diode D2 is electrically connected to the output terminal of the signal transmission module. The characteristics of the first diode D1 and the second diode D2 are as follows: the larger the current flowing through the diode, the smaller the on-resistance; when almost no current flows, the on-resistance is infinite, exhibiting a positive relationship. These characteristics are used to switch the through circuit and the bypass attenuation circuit on and off.
[0055] In one embodiment, the second switching circuit includes a nineteenth resistor R19, a fifth transistor Q5, a twenty-second resistor, a second field-effect transistor Q4, and a third inductor L3. The first terminal of the nineteenth resistor R19 is connected to the collector of the first transistor Q1, and the second terminal of the nineteenth resistor R19 is connected to the base of the fifth transistor Q5. The emitter of the fifth transistor Q5 is grounded, and its collector is connected to the first terminal of the twenty-second resistor and the gate of the second field-effect transistor Q4. The second terminal of the twenty-second resistor is connected to a second reference voltage source and the source of the second field-effect transistor Q4, and the drain of the second field-effect transistor Q4 is connected to the second terminal of the eighteenth resistor. The first terminal of the eighteenth resistor is connected to the second terminal of the third inductor L3, and the first terminal of the third inductor L3 is connected to the anode of the second diode D2.
[0056] When the antenna signal is detected to be normal, if the output voltage of detector U3 is higher than a certain amplitude, the output voltage of detector U3 is compared with the voltage at the non-inverting input of comparator U2. If it is higher than the voltage at the non-inverting input, comparator U2 outputs a low voltage. The base voltage of the third transistor Q3 in the first switching circuit is approximately 0V, so transistor Q3 remains off. The base voltage of the fifth transistor Q5 is approximately 3.3V, so at this time, the fifth transistor Q5 is on, the third transistor Q3 is off, and the second field-effect transistor Q4 is on (both the first field-effect transistor Q2 and the second field-effect transistor Q4 are PMOS transistors off). The conduction condition is that the voltage between VGS is less than Vth(on); therefore, the gate of the second field-effect transistor Q4 is close to 0 potential and is in the source-drain conduction state. The first field-effect transistor Q2 is off, and the current forms a loop through the second field-effect transistor Q4, the eighteenth resistor, the third inductor L3, and the fourth inductor L4 (forming a complete power supply path, allowing current to flow through the second diode D2, thus enabling the second diode D2 to transmit high-frequency signals). The second diode D2 turns on, the first diode D1 remains off, and the third inductor L3 and the fourth inductor L4 are used for isolation to prevent RF signals from crossing to ground or affecting the power supply. At this time, the signal output from the directional coupler U1 is transmitted through the pass-through circuit.
[0057] When an overload is detected at the coupling terminal, such as when the output voltage of detector U3 is lower than a certain amplitude, the output voltage of detector U3 is compared with the voltage at the non-inverting input of comparator U2. If it is lower than the voltage, comparator U2 outputs a high voltage. At this time, the base voltage of the third transistor Q3 in the first switching circuit is about 3.3V, while the base voltage of the fifth transistor Q5 is about 0V. Therefore, the third transistor Q3 is turned on, the fifth transistor Q5 is turned off, the first field-effect transistor Q2 is turned on, and the second field-effect transistor Q4 is turned off. The current forms a circuit through the first field-effect transistor Q2, the thirteenth resistor R13, the first inductor L1, the first diode D1, and the second inductor L2. The first diode D1 is turned on, and the second diode D2 remains turned off.
[0058] Optionally, the attenuator includes a fifteenth resistor R15, a sixteenth resistor R16, and a seventeenth resistor R17. The second terminal of the fifteenth resistor R15 is grounded, its first terminal is connected to the output terminal of the coupling circuit, and its first terminal is connected to the first terminal of the fifteenth resistor R15. The second terminal of the fifteenth resistor R15 is connected to the first terminal of the seventeenth resistor R17 and the anode of the first diode D1. The second terminal of the seventeenth resistor R17 is grounded. The fifteenth resistor R15, sixteenth resistor R16, and seventeenth resistor R17 form a π-type attenuator, specifically with an attenuation of 30dB. The attenuation range can be adjusted using the fifteenth resistor R15, sixteenth resistor R16, and seventeenth resistor R17. In this case, the signal output from the directional coupler U1 is attenuated by 30dB through a bypass, completing overload protection. The insertion loss of the direct circuit is approximately -3dB, and the insertion loss is approximately -30dB when the signal transmission path is adjusted to a bypass attenuation circuit.
[0059] The anti-saturation signal transmission circuit provided in this application includes a coupling circuit, an overload detection module, a switching module, and a signal transmission module equipped with a bypass attenuation circuit. The input terminal of the coupling circuit receives the antenna signal, and the output terminal is connected to the signal transmission module. The coupling terminal is connected to the detection terminal of the overload detection module. The bypass attenuation circuit is equipped with an attenuator. The overload detection module outputs an overload signal to the switching module when it detects a power overload at the coupling terminal. The switching module controls the bypass attenuation circuit to conduct when it detects an overload signal, so that the bypass attenuation circuit transmits the signal output by the coupling circuit. This embodiment of the application can attenuate the signal output by the coupling circuit through the bypass attenuation circuit equipped with an attenuator when an overload signal occurs, thereby achieving overload protection, avoiding signal distortion and damage to circuit components, effectively extending the service life of the receiver and improving its reliability.
[0060] The terms "first," "second," "third," "fourth," "1," "2," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in a sequence other than that shown in the illustrations or text descriptions.
[0061] It should be understood that although arrows indicate various operation steps in the flowcharts of this application's embodiments, the order in which these steps are implemented is not limited to the order indicated by the arrows. Unless explicitly stated herein, in some implementation scenarios of this application's embodiments, the implementation steps in each flowchart can be executed in other orders as required. Furthermore, some or all steps in each flowchart, based on the actual implementation scenario, may include multiple sub-steps or multiple stages. Some or all of these sub-steps or stages can be executed at the same time, and each sub-step or stage can also be executed at different times. In scenarios where execution times differ, the execution order of these sub-steps or stages can be flexibly configured according to requirements, and this application's embodiments do not limit this.
[0062] The above description is only an optional implementation method for some implementation scenarios of this application. It should be noted that for those skilled in the art, other similar implementation methods based on the technical concept of this application without departing from the technical concept of this application also fall within the protection scope of the embodiments of this application.
Claims
1. A signal transmission circuit with anti-saturation properties, characterized in that, It includes a coupling circuit, an overload detection module, a switching module, and a signal transmission module equipped with a bypass attenuation circuit. The input end of the coupling circuit receives the antenna signal, the output end is connected to the signal transmission module, the coupling end is connected to the detection end of the overload detection module, and the bypass attenuation circuit is equipped with an attenuator. The overload detection module is used to output an overload signal to the switching module when a power overload is detected at the coupling terminal; The switching module is used to control the bypass attenuation circuit to turn on when the overload signal is detected, so that the bypass attenuation circuit transmits the signal output by the coupling circuit.
2. The anti-saturation signal transmission circuit according to claim 1, characterized in that, The coupling circuit includes a directional coupler, a seventh capacitor, and a fourteenth resistor. The first end of the seventh capacitor is connected to the antenna, and the other end is connected to the signal output terminal of the directional coupler. The coupling terminal of the directional coupler is connected to the overload detection module. The first end of the fourteenth resistor is connected to the impedance matching pin of the directional coupler, and the second end is grounded. The output terminal of the directional coupler is connected to the signal transmission module.
3. The anti-saturation signal transmission circuit according to claim 1, characterized in that, The overload detection module includes a detector circuit and a comparator circuit. The detection terminal of the detector circuit is connected to the coupling circuit, the output terminal of the detector circuit is connected to the input terminal of the comparator circuit, and the output terminal of the comparator circuit is connected to the switch module.
4. The anti-saturation signal transmission circuit according to claim 3, characterized in that, The detection circuit includes a detector, a first resistor, a fourth resistor, a third capacitor, an eighth resistor, and a fifth capacitor. The first end of the first resistor is connected to the first end of the fourth resistor and the coupling end of the coupling circuit. The second end of the first resistor is connected to a first reference voltage source and the voltage terminal of the detector. The second end of the fourth resistor is connected to the first end of the third capacitor. The second end of the third capacitor is connected to the RF input terminal of the detector. The enable pin of the detector is connected to the first end of the eighth resistor, the first end of the fifth capacitor, and the first reference voltage source. The second ends of the eighth resistor and the fifth capacitor are grounded. The output terminal of the detector is connected to the comparator circuit.
5. The anti-saturation signal transmission circuit according to claim 3, characterized in that, The comparison circuit includes a comparator, a sixth resistor, a seventh resistor, a tenth resistor, and a ninth resistor. The overload signal is low level. The inverting input of the comparator is connected to the output of the detector circuit. The first end of the sixth resistor is connected to a second reference voltage source, and the second end is connected to the second end of the sixth resistor, the first end of the ninth resistor, and the first end of the seventh resistor. The second end of the seventh resistor is connected to the non-inverting input of the comparator and the first end of the tenth resistor. The second end of the tenth resistor is connected to the output of the comparator.
6. The anti-saturation signal transmission circuit according to claim 5, characterized in that, The signal transmission module further includes a through circuit, and the switching module includes a first transistor, a twentieth resistor, a first switching circuit, and a second switching circuit. The base of the first transistor is connected to the output terminal of the comparator and the control terminal of the first switching circuit. The first switching circuit is connected to the bypass attenuation circuit to control the bypass attenuation circuit to be turned on or off. The collector of the first transistor is connected to the control terminal of the second switching circuit and the second terminal of the twentieth resistor. The first terminal of the twentieth resistor is connected to the second reference voltage source, and the emitter is grounded. The second switching circuit is connected to the through circuit to control the through circuit to turn on or off.
7. The anti-saturation signal transmission circuit according to claim 6, characterized in that, Both the through circuit and the bypass attenuation circuit include an isolation inductor and an isolation capacitor. One end of the isolation inductor is grounded, and the other end is connected to the first end of the isolation capacitor. The second end of the isolation capacitor is connected to the output terminal of the signal transmission module.
8. The anti-saturation signal transmission circuit according to claim 6, characterized in that, The bypass attenuation circuit is connected in series with a first diode. The first switching circuit includes a third transistor, a twenty-first resistor, a first field-effect transistor, and a thirteenth resistor. The base of the third transistor is connected to the output terminal of the comparator. The emitter of the third transistor is grounded, and the collector is connected to the first terminal of the twenty-first resistor and the gate of the first field-effect transistor. The second terminal of the twenty-first resistor is connected to the first reference voltage source and the source of the first field-effect transistor. The drain of the first field-effect transistor is connected to the first terminal of the thirteenth resistor. The second terminal of the thirteenth resistor is connected to the anode of the first diode. The cathode of the first diode is electrically connected to the output terminal of the bypass attenuation circuit.
9. The anti-saturation signal transmission circuit according to claim 8, characterized in that, The through circuit includes a second diode. The circuit structure of the second switching circuit is the same as that of the first switching circuit. The output terminal of the second switching circuit is connected to the anode of the second diode, and the cathode of the second diode is electrically connected to the output terminal of the signal transmission module.
10. The anti-saturation signal transmission circuit according to claim 8, characterized in that, The attenuator includes a fifteenth resistor, a sixteenth resistor, and a seventeenth resistor. The second end of the fifteenth resistor is grounded, and its first end is connected to the output terminal of the coupling circuit and the first end of the fifteenth resistor. The second end of the fifteenth resistor is connected to the first end of the seventeenth resistor and the anode of the first diode. The second end of the seventeenth resistor is grounded.