A high-stable local oscillator module for a receiver

Abstract

The utility model relates to receiver technical field, concretely relates to a receiver high -stable local oscillator module, including active crystal oscillator, phase detector, low pass filter, voltage -controlled oscillator, frequency divider, stabiliser and thermostat, stabiliser includes power supply, reference circuit and stabilizing circuit, stabiliser is used to provide stable power Vout, thermostat is used to provide constant working temperature, in the utility model, stabiliser is used to provide stable power Vout, and the interference is suppressed from power supply head, avoids active crystal oscillator, voltage -controlled oscillator and appears work point deviation because of power supply instability, and the frequency drift risk of local oscillator signal is reduced greatly, and thermostat can detect the inside temperature of module in real time, and the temperature detection signal is enhanced through amplifier circuit, and the temperature is accurately adjusted through control electric heating wire, and the core component is maintained in constant working environment, and the influence of temperature change on component parameter is eliminated.

Description

Technical Field

[0001] This utility model relates to the field of receiver technology, and more specifically, to a high-stability local oscillator module for a receiver. Background Technology

[0002] The local oscillator module is the core component for realizing signal frequency conversion. The frequency stability of its output local oscillator signal directly determines the receiver's reception accuracy, anti-interference capability, and signal demodulation quality. If the local oscillator signal frequency drifts, it will cause the receiver to be unable to accurately capture the target signal, and may even cause problems such as signal distortion, signal-to-noise ratio reduction, or reception interruption. Therefore, the high stability design of the local oscillator module is the key to improving receiver performance.

[0003] The utility model patent with publication number CN222966986U discloses an ultra-wideband receiver that automatically identifies the receiving frequency. The structure is as follows: the input end of the frequency detection module receives radio frequency signals, and the output end of the frequency detection module is connected to the input end of the main control module; the output end of the main control module is connected to the input end of the filter component and the input end of the frequency conversion module respectively; the input end of the filter component is also used to receive radio frequency signals, and the output end of the filter component is connected to the input end of the frequency conversion module; the output end of the frequency conversion module is connected to the input end of the main control module.

[0004] Although this utility model automatically identifies the frequency of the received radio frequency signal through the frequency detection module, the main control module sends instructions to the filtering component to select and pass through a specific signal frequency band based on the frequency magnitude, and calculates the local oscillator frequency based on the frequency magnitude, and then mixes the local oscillator frequency and the processed radio frequency signal through the frequency conversion module to keep the amplitude of the output intermediate frequency signal constant, thereby simplifying the subsequent circuit structure and optimizing the dynamic range, the local oscillator signal is affected by the environment when it is generated, and cannot meet the high stability requirements of high-precision receivers for the local oscillator signal. Utility Model Content

[0005] The purpose of this invention is to provide a highly stable local oscillator module for a receiver to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: A receiver high-stability local oscillator module includes an active crystal oscillator, a phase detector, a low-pass filter, a voltage-controlled oscillator, a frequency divider, a voltage regulator, and a thermostat. The active crystal oscillator, the phase detector, the low-pass filter, and the voltage-controlled oscillator are electrically connected in sequence. The voltage-controlled oscillator outputs a local oscillator signal, and the frequency divider is connected between the voltage-controlled oscillator and the phase detector. The voltage regulator includes a power supply, a reference circuit, and a voltage regulator circuit. The power supply provides a power supply VCC. The reference circuit provides a reference voltage Vref based on a Kuijk bandgap reference source. The two input terminals of the voltage regulator circuit are connected to the power supply VCC and the reference voltage Vref, respectively. The voltage regulator circuit is an LDO voltage regulator circuit. The voltage regulator is used to provide a stable power supply Vout. The thermostat includes a detection circuit, an amplification circuit, and a temperature control circuit. The detection circuit outputs a detection signal based on a Wheatstone bridge. The amplification circuit amplifies the detection signal. The temperature control circuit controls the working state of the heating wire H based on the detection signal. The thermostat provides a constant operating temperature.

[0007] Preferably, the reference circuit includes resistors R1, R2, and R3, transistors Q1 and Q2, and operational amplifier U1, wherein transistors Q1 and Q2 are both NPN transistors. The first terminal of resistor R1 is connected to the output terminal of operational amplifier U1, and the second terminal of resistor R1 is connected to the inverting input terminal of operational amplifier U1. The first terminal of resistor R2 is connected to the output terminal of operational amplifier U1, and the second terminal of resistor R2 is connected to the non-inverting input terminal of operational amplifier U1. Operational amplifier U1 outputs a reference voltage Vref. The base and collector of transistor Q1 are both connected to the second terminal of resistor R1. The emitter of transistor Q1 is connected to the first terminal of resistor R3, and the second terminal of resistor R3 is grounded. The base and collector of transistor Q2 are both connected to the second terminal of resistor R2, and the emitter of transistor Q2 is grounded. Preferably, the power supply outputs power VCC, and the voltage regulator circuit includes a MOSFET, an operational amplifier U2, resistors R4 and R5, wherein the MOSFET is an enhancement-mode NMOS transistor. The drain of the MOSFET is connected to the power supply VCC, and the source of the MOSFET outputs a stable power supply Vout. The first terminal of resistor R4 is connected to the source of the MOSFET, the second terminal of resistor R4 is connected to the first terminal of resistor R5, and the second terminal of resistor R5 is grounded. The non-inverting input terminal of operational amplifier U2 is connected to the reference voltage Vref, the inverting input terminal of operational amplifier U2 is connected to the second terminal of resistor R4, and the output terminal of operational amplifier U2 is connected to the gate of the MOSFET. These two settings provide a continuous and stable power supply Vout, ensuring a stable power supply for core components such as active crystal oscillators and voltage-controlled oscillators. They also help avoid the deviation of the operating point of components caused by voltage instability, further reducing the possibility of local oscillator signal frequency drift.

[0008] Preferably, the detection circuit includes resistors R6, R7, and R8, and a temperature-sensing resistor RT. The first terminal of resistor R6 is connected to the first terminal of resistor R8, the second terminal of resistor R8 is grounded, the second terminal of resistor R6 is connected to the power supply Vout, the first terminal of resistor R7 is connected to the second terminal of resistor R6, the second terminal of resistor R7 is connected to the second terminal of temperature measuring resistor RT, and the first terminal of temperature measuring resistor RT is grounded. Preferably, the amplifier circuit includes an operational amplifier U3, a resistor R9, a resistor R10, and a capacitor C; The non-inverting input of operational amplifier U3 is connected to the second terminal of resistor R7, the inverting input of operational amplifier U3 is connected to the first terminal of resistor R6, the output of operational amplifier U3 is connected to the first terminal of resistor R10, the first terminal of resistor R9 is connected to the inverting input of operational amplifier U3, the second terminal of resistor R9 is connected to the output of operational amplifier U3, the first terminal of capacitor C is connected to the first terminal of resistor R9, and the second terminal of capacitor C is connected to the second terminal of resistor R9. Preferably, the temperature control circuit includes a resistor R11, a heating wire H, and a transistor Q3, wherein the transistor Q3 is an NPN transistor. The first end of resistor R11 is connected to the second end of resistor R10, the second end of resistor R11 is grounded, the base of transistor Q3 is connected to the second end of resistor R10, the collector of transistor Q3 is connected to power supply Vout, the emitter of transistor Q3 is connected to the first end of heating wire H, and the second end of heating wire H is grounded. These three settings utilize the temperature-sensing resistor RT's resistance to change with temperature, converting minute temperature fluctuations into a recognizable voltage detection signal. The amplifier circuit amplifies this weak temperature detection signal, and the temperature control circuit uses transistor Q3 as a switching element to precisely control the on / off state of the heating wire H based on the amplified detection signal. This allows for real-time and precise temperature detection, signal amplification, and heating control within the module, maintaining the core components at a constant operating temperature and eliminating interference from temperature changes on component parameters. This provides a temperature-level guarantee for the long-term stable output of the local oscillator signal.

[0009] Compared with the prior art, the beneficial effects of this utility model are: 1. This utility model, by setting a regulator with a Kuijk-type bandgap reference source and an LDO voltage regulator circuit, utilizes the low temperature coefficient of the Kuijk-type bandgap reference source to generate a high-precision reference voltage Vref that is unaffected by temperature changes. On the other hand, using the reference voltage Vref as a reference, the LDO voltage regulator circuit linearly regulates the power supply VCC, effectively filtering out power ripple and voltage fluctuations, and outputting a stable power supply Vout. This suppresses interference from the power supply head, avoids operating point shifts of active crystal oscillators and voltage-controlled oscillators due to power instability, and significantly reduces the risk of frequency drift of the local oscillator signal.

[0010] 2. This utility model achieves dual assurance of local oscillator signal stability by setting up a combination structure of a thermostat and a phase-locked loop feedback loop: the thermostat can detect the internal temperature of the module in real time, enhance the temperature detection signal through an amplification circuit, and control the heating wire to precisely adjust the temperature, maintaining the core components in a constant working environment and eliminating the influence of temperature changes on component parameters; at the same time, the phase-locked loop composed of a phase detector, a voltage-controlled oscillator, and a frequency divider can compare the phase and frequency of the voltage-controlled oscillator output signal with the reference signal in real time, and dynamically correct the voltage-controlled oscillator output frequency through the error signal, further offsetting small frequency deviations, ensuring long-term stability of the local oscillator signal, and significantly improving the receiver's receiving accuracy, anti-interference capability, and signal demodulation quality. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a schematic diagram of the voltage regulator in this utility model; Figure 3 This is a circuit diagram of the reference circuit in this utility model; Figure 4 This is a circuit diagram of the voltage regulator circuit in this utility model; Figure 5 This is a schematic diagram of the thermostat in this utility model; Figure 6 This is the circuit diagram of the thermostat in this utility model; In the picture: 100. Active crystal oscillator; 200. Phase detector; 300. Low-pass filter; 400. Voltage-controlled oscillator; 500, frequency divider; 600. Voltage regulator; 601. Power supply; 602. Reference circuit; 603. Voltage regulator circuit; 700. Thermostat; 701. Detection circuit; 702. Amplification circuit; 703. Temperature control circuit. Detailed Implementation

[0012] The technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0013] Please see Figures 1-6 The present invention provides the following technical solution: A high-stability local oscillator module for a receiver includes an active crystal oscillator 100, a phase detector 200, a low-pass filter 300, a voltage-controlled oscillator 400, a frequency divider 500, a voltage regulator 600, and a thermostat 700. The active crystal oscillator 100, phase detector 200, low-pass filter 300, and voltage-controlled oscillator 400 are electrically connected in sequence. The voltage-controlled oscillator 400 outputs a local oscillator signal. The frequency divider 500 is connected between the voltage-controlled oscillator 400 and the phase detector 200. The phase detector 200, voltage-controlled oscillator 400, and frequency divider 500 constitute the core feedback loop of a phase-locked loop. If the output frequency of the voltage-controlled oscillator 400 is too high, the frequency of the feedback signal after frequency division by the frequency divider 500 will also be too high. The phase detector 200 will detect this deviation and output an error signal to reduce the voltage. If the output frequency of the voltage-controlled oscillator 400 is too low, the frequency of the feedback signal after frequency division will also be too low. The phase detector 200 will output an error signal to increase the voltage. After being filtered by the low-pass filter 300, this error signal will be fed back to the control terminal of the voltage-controlled oscillator 400 to adjust its output frequency until the phase and frequency of the feedback signal are consistent with the reference signal, and finally achieve a highly stable output of the local oscillator signal. The voltage regulator 600 includes a power supply 601, a reference circuit 602, and a voltage regulator circuit 603. The power supply 601 provides the power supply VCC. The reference circuit 602 provides a reference voltage Vref based on a Kuijk-type bandgap reference source. The two input terminals of the voltage regulator circuit 603 are connected to the power supply VCC and the reference voltage Vref, respectively. The voltage regulator circuit 603 is an LDO voltage regulator circuit. The voltage regulator 600 provides a stable power supply Vout to power the active crystal oscillator 100, phase detector 200, low-pass filter 300, voltage-controlled oscillator 400, frequency divider 500, and thermostat 700. It filters out ripple and voltage fluctuations from the power supply head, preventing the active crystal oscillator 100 and voltage-controlled oscillator 400 from operating point shifts due to power instability, and significantly reducing the risk of local oscillator signal frequency drift. The thermostat 700 includes a detection circuit 701, an amplifier circuit 702, and a temperature control circuit 703. The detection circuit 701 outputs a detection signal based on a Wheatstone bridge, the amplifier circuit 702 amplifies the detection signal, and the temperature control circuit 703 controls the working state of the heating wire H based on the detection signal. The thermostat 700 is used to provide a constant operating temperature, reduce the impact of temperature changes on component parameters, and further ensure the stability of the local oscillator signal.

[0014] In this embodiment, please refer to Figure 2 , Figure 3 and Figure 4 The reference circuit 602 includes resistors R1, R2, and R3, transistors Q1 and Q2, and operational amplifier U1. Transistors Q1 and Q2 are both NPN transistors. The first terminal of resistor R1 is connected to the output terminal of operational amplifier U1, and the second terminal of resistor R1 is connected to the inverting input terminal of operational amplifier U1. The first terminal of resistor R2 is connected to the output terminal of operational amplifier U1, and the second terminal of resistor R2 is connected to the non-inverting input terminal of operational amplifier U1. Operational amplifier U1 outputs a reference voltage Vref. The base and collector of transistor Q1 are both connected to the second terminal of resistor R1. The emitter of transistor Q1 is connected to the first terminal of resistor R3, and the second terminal of resistor R3 is grounded. The base and collector of transistor Q2 are both connected to the second terminal of resistor R2, and the emitter of transistor Q2 is grounded. By utilizing the characteristic that the emitter voltage of NPN transistors Q1 and Q2 changes with temperature, and with the voltage division and feedback adjustment of resistors R1, R2, and R3, the influence of temperature changes on the output signal is offset, so that the reference voltage Vref output by operational amplifier U1 has a low temperature coefficient and remains stable in different temperature environments.

[0015] Specifically, the power supply 601 outputs power supply VCC, and the voltage regulator circuit 603 includes a MOSFET, an operational amplifier U2, resistors R4 and R5, and the MOSFET is an enhancement-type NMOS transistor. The drain of the MOSFET is connected to the power supply VCC, and the source of the MOSFET outputs a stable power supply Vout. The first terminal of resistor R4 is connected to the source of the MOSFET, the second terminal of resistor R4 is connected to the first terminal of resistor R5, and the second terminal of resistor R5 is grounded. The non-inverting input of operational amplifier U2 is connected to the reference voltage Vref, the inverting input of operational amplifier U2 is connected to the second terminal of resistor R4, and the output of operational amplifier U2 is connected to the gate of the MOSFET. By comparing the reference voltage Vref with the voltage divider signals of resistors R4 and R5, operational amplifier U2 adjusts the gate voltage of the MOSFET in real time, thereby controlling the conduction of the MOSFET and achieving linear regulation of the power supply VCC. This effectively filters out ripple and voltage fluctuations in the power supply VCC and ensures the stability of the output power supply Vout.

[0016] In this embodiment, please refer to Figure 5 and Figure 6 The detection circuit 701 includes resistors R6, R7, and R8, and a temperature measuring resistor RT. The first terminal of resistor R6 is connected to the first terminal of resistor R8, the second terminal of resistor R8 is grounded, and the second terminal of resistor R6 is connected to the power supply Vout. The first terminal of resistor R7 is connected to the second terminal of resistor R6, and the second terminal of resistor R7 is connected to the second terminal of temperature sensing resistor RT. The first terminal of temperature sensing resistor RT is grounded. The resistance value of temperature sensing resistor RT changes linearly or in a fixed manner with temperature. Through the Wheatstone bridge structure, the resistance change can be converted into a voltage signal change, accurately capturing the tiny temperature fluctuations inside the module and improving the detection sensitivity.

[0017] Specifically, the amplifier circuit 702 includes an operational amplifier U3, resistor R9, resistor R10, and capacitor C; The non-inverting input of operational amplifier U3 is connected to the second terminal of resistor R7, the inverting input of operational amplifier U3 is connected to the first terminal of resistor R6, the output of operational amplifier U3 is connected to the first terminal of resistor R10, the first terminal of resistor R9 is connected to the inverting input of operational amplifier U3, the second terminal of resistor R9 is connected to the output of operational amplifier U3, the first terminal of capacitor C is connected to the first terminal of resistor R9, and the second terminal of capacitor C is connected to the second terminal of resistor R9. Since the detected signal may be relatively small, an amplifier circuit 702 is needed to amplify it.

[0018] Furthermore, the temperature control circuit 703 includes a resistor R11, a heating wire H, and a transistor Q3, wherein the transistor Q3 is an NPN transistor; The first terminal of resistor R11 is connected to the second terminal of resistor R10, and the second terminal of resistor R11 is grounded. The base of transistor Q3 is connected to the second terminal of resistor R10, the collector of transistor Q3 is connected to the power supply Vout, the emitter of transistor Q3 is connected to the first terminal of heating wire H, and the second terminal of heating wire H is grounded. Transistor Q3 is a switching transistor. When the base of transistor Q3 is at a high level, transistor Q3 is turned on and heating wire H is working. When the base of transistor Q3 is at a low level, transistor Q3 is turned off and heating wire H is not working.

[0019] When the high-stability local oscillator module of the receiver of this utility model is in use, the power supply 601 outputs the initial power supply VCC to provide input power for the subsequent circuits of the voltage regulator 600. The reference circuit 602 provides a reference voltage Vref based on the Kuijk type bandgap reference source. In the voltage regulator circuit 603, the drain of the MOS transistor is connected to the power supply VCC, and the source of the MOS transistor outputs the power to be stabilized. The non-inverting input terminal of the operational amplifier U2 is connected to the reference voltage Vref, the inverting input terminal of the operational amplifier U2 is connected to the voltage divider point of resistors R4 and R5, and the output terminal of the operational amplifier U2 is connected to the gate of the MOS transistor. The operational amplifier U2 compares the reference voltage Vref with the voltage divider signal in real time and adjusts the gate voltage of the MOS transistor to control its conduction state. Finally, it outputs a stable power supply Vout. The stable power supply Vout supplies power to the active crystal oscillator 100, phase detector 200, low-pass filter 300, voltage-controlled oscillator 400, frequency divider 500 and thermostat 700, suppressing power supply interference from the source. Resistors R6, R7, and R8, along with the temperature-sensing resistor RT, form a Wheatstone bridge. At the desired temperature, the resistances of these resistors are equal to those of RT. When the temperature changes, the resistance of RT changes synchronously, causing the bridge to become unbalanced and outputting a temperature-corresponding detection signal. Operational amplifier U3 amplifies the weak detection signal and outputs it to the temperature control circuit 703 via resistor R10. When the amplified detection signal (i.e., when the temperature is below the set value) causes the base of transistor Q3 to be high, transistor Q3 conducts, energizing the heating wire H. When the amplified detection signal (i.e., when the temperature reaches the set value) causes the base of transistor Q3 to be low, transistor Q3 is cut off, and the heating wire H stops working, ultimately maintaining a constant internal temperature for the module. The active crystal oscillator 100, under a constant power supply (Vout) and temperature environment, outputs a stable fundamental signal and transmits it to the phase detector 200. The voltage-controlled oscillator 400, under the same power supply (Vout) and temperature environment, initially outputs a local oscillator signal. A portion of this signal is output as the final local oscillator signal, while the remaining portion is fed into a frequency divider 500. After frequency division, a feedback signal is output and transmitted to the phase detector 200. The phase detector 200 receives the fundamental signal and the feedback signal, compares their phase and frequency differences, and outputs a corresponding error signal. This error signal is fed into a low-pass filter 300 to filter out high-frequency components, resulting in a smooth DC control signal. This control signal is fed back to the control terminal of the voltage-controlled oscillator 400, adjusting its internal oscillation parameters to change the frequency of the local oscillator signal output by the voltage-controlled oscillator 400 until the feedback signal output by the frequency divider 500 is completely consistent with the phase and frequency of the fundamental signal. At this point, the phase detector 200 outputs a zero error signal, and the voltage-controlled oscillator 400 stably outputs the local oscillator signal, achieving high stability.

[0020] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A high-stability local oscillator module for a receiver, comprising an active crystal oscillator (100), a phase detector (200), a low-pass filter (300), a voltage-controlled oscillator (400), a frequency divider (500), a voltage regulator (600), and a thermostat (700), wherein the active crystal oscillator (100), the phase detector (200), the low-pass filter (300), and the voltage-controlled oscillator (400) are electrically connected in sequence, the voltage-controlled oscillator (400) outputs a local oscillator signal, and the frequency divider (500) is connected between the voltage-controlled oscillator (400) and the phase detector (200); characterized in that: The voltage regulator (600) includes a power supply (601), a reference circuit (602), and a voltage regulator circuit (603). The power supply (601) provides a power supply VCC. The reference circuit (602) provides a reference voltage Vref based on a Kuijk type bandgap reference source. The two input terminals of the voltage regulator circuit (603) are connected to the power supply VCC and the reference voltage Vref, respectively. The voltage regulator circuit (603) is an LDO voltage regulator circuit. The voltage regulator (600) provides a stable power supply Vout. The thermostat (700) includes a detection circuit (701), an amplification circuit (702), and a temperature control circuit (703). The detection circuit (701) outputs a detection signal based on a Wheatstone bridge. The amplification circuit (702) amplifies the detection signal. The temperature control circuit (703) controls the working state of the heating wire H based on the detection signal. The thermostat (700) provides a constant working temperature.

2. The receiver high-stability local oscillator module according to claim 1, characterized in that: The reference circuit (602) includes resistors R1, R2, and R3, transistors Q1 and Q2, and operational amplifier U1. Transistors Q1 and Q2 are both NPN transistors. The first terminal of resistor R1 is connected to the output terminal of operational amplifier U1, and the second terminal of resistor R1 is connected to the inverting input terminal of operational amplifier U1. The first terminal of resistor R2 is connected to the output terminal of operational amplifier U1, and the second terminal of resistor R2 is connected to the non-inverting input terminal of operational amplifier U1. Operational amplifier U1 outputs a reference voltage Vref. The base and collector of transistor Q1 are both connected to the second terminal of resistor R1. The emitter of transistor Q1 is connected to the first terminal of resistor R3, and the second terminal of resistor R3 is grounded. The base and collector of transistor Q2 are both connected to the second terminal of resistor R2, and the emitter of transistor Q2 is grounded.

3. The receiver high-stability local oscillator module according to claim 2, characterized in that: The power supply (601) outputs power supply VCC, and the voltage regulator circuit (603) includes a MOS transistor, an operational amplifier U2, a resistor R4 and a resistor R5. The MOS transistor is an enhancement-type NMOS transistor. The drain of the MOSFET is connected to the power supply VCC, and the source of the MOSFET outputs a stable power supply Vout. The first terminal of resistor R4 is connected to the source of the MOSFET, the second terminal of resistor R4 is connected to the first terminal of resistor R5, and the second terminal of resistor R5 is grounded. The non-inverting input of operational amplifier U2 is connected to the reference voltage Vref, the inverting input of operational amplifier U2 is connected to the second terminal of resistor R4, and the output of operational amplifier U2 is connected to the gate of the MOSFET.

4. The receiver high-stability local oscillator module according to claim 1, characterized in that: The detection circuit (701) includes resistors R6, R7, and R8, and a temperature measuring resistor RT; The first terminal of resistor R6 is connected to the first terminal of resistor R8, the second terminal of resistor R8 is grounded, the second terminal of resistor R6 is connected to the power supply Vout, the first terminal of resistor R7 is connected to the second terminal of resistor R6, the second terminal of resistor R7 is connected to the second terminal of temperature measuring resistor RT, and the first terminal of temperature measuring resistor RT is grounded.

5. The receiver high-stability local oscillator module according to claim 4, characterized in that: The amplifier circuit (702) includes an operational amplifier U3, resistors R9 and R10, and capacitor C; The non-inverting input of operational amplifier U3 is connected to the second terminal of resistor R7, the inverting input of operational amplifier U3 is connected to the first terminal of resistor R6, the output of operational amplifier U3 is connected to the first terminal of resistor R10, the first terminal of resistor R9 is connected to the inverting input of operational amplifier U3, the second terminal of resistor R9 is connected to the output of operational amplifier U3, the first terminal of capacitor C is connected to the first terminal of resistor R9, and the second terminal of capacitor C is connected to the second terminal of resistor R9.

6. The receiver high-stability local oscillator module according to claim 5, characterized in that: The temperature control circuit (703) includes a resistor R11, a heating wire H, and a transistor Q3, wherein the transistor Q3 is an NPN transistor; The first terminal of resistor R11 is connected to the second terminal of resistor R10, and the second terminal of resistor R11 is grounded. The base of transistor Q3 is connected to the second terminal of resistor R10, the collector of transistor Q3 is connected to the power supply Vout, the emitter of transistor Q3 is connected to the first terminal of heating wire H, and the second terminal of heating wire H is grounded.

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