Wireless direction finder circuit and wireless direction finder

Abstract

The application discloses a wireless direction finder circuit and a wireless direction finder, and relates to the technical field of wireless direction finding. The wireless direction finder circuit comprises a local oscillator signal input end, a mixed frequency detection circuit, a rectifier circuit, a main control circuit and a variable sound output circuit. The mixed frequency detection circuit generates a mixed frequency signal according to a wireless signal and a local oscillator signal. The rectifier circuit converts the mixed frequency signal into a first direct current signal. The main control circuit outputs a variable sound control signal when the voltage value of the first direct current signal is greater than or equal to a preset voltage value. The variable sound output circuit outputs a corresponding first audio signal according to the mixed frequency signal when the variable sound control signal is not received, and outputs a second audio signal of a variable frequency according to the variable sound control signal and the mixed frequency signal when the variable sound control signal is received, so that the user can be prompted that the signal strength is large at the moment and the signal source has entered a preset distance range. The application assists positioning through a dual change mechanism of tone and volume, and improves positioning efficiency and environmental adaptability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wireless direction finding technology, in particular to a wireless direction finder circuit and a wireless direction finder. BACKGROUND

[0002] Wireless direction finding is an outdoor competitive activity that combines technology and sports. Participants need to locate and find multiple hidden radio signal sources in a wide natural area (such as a park, forest, etc.). These signal sources periodically emit wireless signals of specific frequencies, which participants receive using a specialized wireless direction finder. The wireless direction finder prompts the participants about the distance and direction of the signal source through changes in volume based on the received signal strength. The goal of the participants is to find the correct signal source as accurately as possible within the specified time.

[0003] Existing wireless direction finders usually emit sound signals of corresponding sizes according to the strength of the wireless signals emitted by the signal sources. However, in cases where the signal strength changes are not obvious, it is difficult for participants to accurately judge the changes in distance, especially when approaching the signal source, the volume changes are subtle and difficult to accurately perceive. Or in a complex environment, background noise may mask the details of the volume change, leading to inaccurate positioning or even misjudgment. For example, in outdoor competitions, wind noise, traffic noise, etc. may affect the hearing judgment of the participants. For the above reasons, participants need to concentrate highly and repeatedly try to determine the location of the signal source, which affects the efficiency and experience of the competition.

[0004] The above content is only used to assist in understanding the technical solutions of the present application and does not represent the acknowledgement of the above content as prior art. SUMMARY

[0005] The main purpose of the present application is to provide a wireless direction finder circuit, which aims to solve the problem that the existing wireless direction finder only relies on volume changes to reflect signal strength, resulting in low positioning efficiency of the signal source.

[0006] To achieve the above purpose, the present application provides a wireless direction finder circuit, the wireless direction finder includes an antenna for receiving wireless signals emitted by a signal source; the wireless direction finder circuit includes:

[0007] a local oscillator signal input end for inputting a local oscillator signal;

[0008] a mixing and detection circuit, a first input end of the mixing and detection circuit is connected with the antenna, and a second input end of the mixing and detection circuit is connected with the local oscillator signal input end; the mixing and detection circuit is used for outputting a corresponding mixing signal according to the wireless signal and the local oscillator signal;

[0009] a rectifier circuit, an input end of the rectifier circuit being connected with a first output end of the mixing and detecting circuit; the rectifier circuit being used for rectifying the mixing signal into a first direct current signal and outputting;

[0010] a main control circuit, a first input end of the main control circuit being connected with an output end of the rectifier circuit; the main control circuit being used for outputting a variable sound control signal when a voltage value of the first direct current signal is greater than or equal to a preset voltage value;

[0011] a variable sound output circuit, a first input end of the variable sound output circuit being connected with a second output end of the mixing and detecting circuit, and a second input end of the variable sound output circuit being connected with a first output end of the main control circuit; the variable sound output circuit being used for outputting a corresponding first audio signal according to the mixing signal when the variable sound control signal is not received, and outputting a corresponding second audio signal according to the variable sound control signal and the mixing signal when the variable sound control signal is received; wherein the frequency of the second audio signal is not equal to the frequency of the first audio signal.

[0012] In an embodiment, the variable sound output circuit comprises a first diode, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first triode and a power amplifier chip.

[0013] One end of the first resistor is connected with the first output end of the main control circuit, the other end of the first resistor and one end of the second resistor are connected with the base of the first triode, the emitter of the first triode is grounded, the anode of the first diode is connected with the first input end of the variable sound output circuit, the cathode of the first diode, one end of the first capacitor, one end of the third resistor and one end of the fourth resistor are connected, the other end of the fourth resistor, the collector of the first triode and one end of the second capacitor and one end of the third capacitor are connected, the other end of the first capacitor, the other end of the third resistor and the other end of the second capacitor are grounded, the other end of the third capacitor, one end of the fourth capacitor and one end of the fifth resistor are connected with the input end of the power amplifier chip, the other end of the fourth capacitor and the other end of the fifth resistor are grounded, and the output end of the power amplifier chip is the output end of the variable sound output circuit.

[0014] In an embodiment, the rectifier circuit comprises a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a fifth capacitor, a sixth capacitor, a seventh capacitor and a second diode.

[0015] One end of the sixth resistor is connected with the power supply end of the rectifier circuit, the other end of the sixth resistor, one end of the seventh resistor and one end of the fifth capacitor are connected with the positive electrode of the second diode, the negative electrode of the second diode, one end of the sixth capacitor and one end of the ninth resistor are connected with the other end of the eighth resistor, the other end of the seventh resistor and the other end of the eighth resistor are grounded, the other end of the ninth resistor and the other end of the seventh capacitor are connected with the output end of the rectifier circuit, the other end of the fifth capacitor is connected with one end of the tenth resistor, and the other end of the tenth resistor is connected with the input end of the rectifier circuit.

[0016] In an embodiment, the wireless direction finder circuit further comprises:

[0017] a signal amplification circuit, a first input end of the signal amplification circuit is connected with the antenna, and an output end of the signal amplification circuit is connected with a first input end of the mixing detection circuit, the signal amplification circuit being configured to amplify the wireless signal output by the antenna and output the amplified wireless signal to the mixing detection circuit;

[0018] a gain adjustment circuit, an output end of the gain adjustment circuit is connected with a second input end of the signal amplification circuit and a third input end of the mixing detection circuit respectively, the gain adjustment circuit being configured to output a corresponding gain adjustment voltage to adjust the amplification multiple of the signal amplification circuit when triggered by a user;

[0019] the master control circuit is configured to output a sound change control signal when the voltage value of the first direct current signal is greater than or equal to the product of the preset voltage value and the amplification multiple.

[0020] In an embodiment, the wireless direction finder circuit further comprises:

[0021] a display circuit, a controlled end of the display circuit is connected with a second output end of the master control circuit;

[0022] the master control circuit is further configured to control the display circuit to display amplification multiple information corresponding to the voltage value of the gain adjustment voltage according to the gain adjustment voltage, and control the display circuit to display signal strength information corresponding to the voltage value of the first direct current signal according to the first direct current signal.

[0023] In an embodiment, the antenna comprises a first antenna and a second antenna, and the signal amplification circuit comprises a first transformer, a second transformer, a third transformer, a fourth transformer, an eighth capacitor, a ninth capacitor, a tenth capacitor, a first double-gate field effect transistor and a third diode.

[0024] The first antenna is connected with a first primary end of the first transformer, a second primary end of the first transformer is grounded, the second antenna is connected with a first secondary end of the first transformer, a second secondary end of the first transformer is connected with a first primary end of the second transformer, a second primary end of the second transformer is grounded, a first secondary end of the second transformer is connected with one end of the eighth capacitor, a second secondary end of the second transformer is grounded, a secondary common end of the second transformer is connected with a first gate of the first double-gate field effect transistor, a second gate of the first double-gate field effect transistor is connected with a power supply end of the signal amplification circuit, a source of the first double-gate field effect transistor is grounded, a drain of the first double-gate field effect transistor is connected with a primary common end of the third transformer, a first primary end of the third transformer is connected with one end of the ninth capacitor, a second primary end of the third transformer and the other end of the ninth capacitor are connected with a negative electrode of the third diode, a positive electrode of the third diode is connected with an output end of the gain adjustment circuit, a first secondary end of the third transformer is connected with a first primary end of the fourth transformer, a second secondary end of the third transformer is grounded, a first secondary end of the fourth transformer is connected with one end of the tenth capacitor, a second secondary end of the fourth transformer and the other end of the tenth capacitor are grounded, and a secondary common end of the fourth transformer is connected with an input end of the mixing and detection circuit.

[0025] In an embodiment, the mixing and detection circuit comprises a second double-gate field effect transistor, a third double-gate field effect transistor, a fourth double-gate field effect transistor, a fifth transformer, a twelfth capacitor, a thirteenth capacitor, a first crystal oscillator, and an output amplification circuit.

[0026] The first gate of the second double-gate field effect transistor, the local oscillator signal input end and the output end of the signal amplification circuit are connected, the second gate of the second double-gate field effect transistor, the second gate of the third double-gate field effect transistor, the second gate of the fourth double-gate field effect transistor and the power supply end of the frequency mixing and detection circuit are connected, the source of the second double-gate field effect transistor, the source of the third double-gate field effect transistor and the source of the fourth double-gate field effect transistor are grounded, the drain of the second double-gate field effect transistor and one end of the twelfth capacitor are connected with the first primary end of the fifth transformer, the second primary end of the fifth transformer and the other end of the twelfth capacitor are connected with the power supply end of the frequency mixing and detection circuit, the first secondary end of the fifth transformer is grounded, the second secondary end of the fifth transformer is connected with the first gate of the third double-gate field effect transistor, the drain of the third double-gate field effect transistor and the output end of the gain adjustment circuit are connected with the input end of the first crystal oscillator, the ground end of the first crystal oscillator is grounded, the output end of the first crystal oscillator is connected with the first gate of the fourth double-gate field effect transistor, the drain of the fourth double-gate field effect transistor and one end of the thirteenth capacitor are connected with the output end of the gain adjustment circuit, the other end of the thirteenth capacitor is connected with the input end of the output amplification circuit, and the output end of the output amplification circuit is connected with the output end of the frequency mixing and detection circuit.

[0027] In an embodiment, the wireless direction finder circuit further comprises:

[0028] A local oscillator signal generation circuit, a controlled end of the local oscillator signal generation circuit is connected with the third output end of the master control circuit, and an output end of the local oscillator signal generation circuit is connected with the local oscillator signal input end; the local oscillator signal generation circuit is used for outputting a local oscillator signal of a corresponding frequency according to a frequency control signal output by the master control circuit.

[0029] The application further provides a wireless direction finder, which comprises an antenna and the wireless direction finder circuit.

[0030] The technical scheme of the present application adopts a wireless direction finder circuit, the wireless direction finder circuit comprising an antenna for receiving wireless signals from a signal source, and comprising a local oscillator signal input end, a mixing detection circuit, a rectifier circuit, a main control circuit and a variable sound output circuit. The antenna can receive wireless signals from the signal source. The mixing detection circuit can mix the received wireless signals with the local oscillator signal input from the local oscillator signal input end to generate a mixed signal. The rectifier circuit can convert the mixed signal generated by the mixing detection circuit into a first direct current signal. The main control circuit can output a variable sound control signal when the voltage value of the first direct current signal is greater than or equal to a preset voltage value. The variable sound output circuit outputs a corresponding first audio signal according to the mixed signal when no variable sound control signal is received, and outputs a corresponding second audio signal according to the variable sound control signal and the mixed signal when the variable sound control signal is received; wherein the frequency of the second audio signal is not equal to that of the first audio signal. In this way, when the variable sound control signal is received, the variable sound output circuit generates the second audio signal based on the variable sound control signal and the mixed signal, and the frequency of the second audio signal is different from that of the first audio signal, prompting the user that the signal source has entered the preset distance range. In this way, the present application uses the tone and volume double prompt mechanism to prompt the positioning information of the signal source, and compared with the prior art, the present application improves the positioning efficiency and environmental adaptability. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort based on the drawings shown.

[0032] Figure 1 A structural schematic diagram of an embodiment of the wireless direction finder circuit provided by the present application is shown in the figure.

[0033] Figure 2 A structural schematic diagram of another embodiment of the wireless direction finder circuit provided by the present application is shown in the figure.

[0034] Figure 3 An electronic circuit diagram of the variable sound output circuit of an embodiment of the wireless direction finder circuit provided by the present application is shown in the figure.

[0035] Figure 4 An electronic circuit diagram of the rectifier circuit of an embodiment of the wireless direction finder circuit provided by the present application is shown in the figure.

[0036] Figure 5 An electronic circuit diagram of the signal amplification circuit of an embodiment of the wireless direction finder circuit provided by the present application is shown in the figure.

[0037] Figure 6 Electronic circuit diagram of the gain adjusting circuit of an embodiment of the wireless direction finder circuit provided in the present application;

[0038] Figure 7 Electronic circuit diagram of the mixing and detecting circuit of an embodiment of the wireless direction finder circuit provided in the present application;

[0039] Figure 8 Electronic circuit diagram of the local oscillator signal generating circuit of an embodiment of the wireless direction finder circuit provided in the present application.

[0040] Brief Description of the Drawings

[0041]

[0042] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without any creative work fall within the scope of protection of the present application.

[0044] It should be noted that all the directionality indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directionality indications also change accordingly.

[0045] In addition, the description involving “first”, “second” and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined with “first”, “second” can explicitly or implicitly include at least one of the features. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the fact that a person skilled in the art can realize it, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is also not within the scope of protection claimed by the present application.

[0046] The existing wireless direction finder usually emits a sound signal of corresponding size according to the strength of the wireless signal emitted by the signal source. However, in the case where the signal strength changes are not obvious, it is difficult for the participants to accurately judge the change of the distance, especially when approaching the signal source, the volume changes slightly and it is difficult to accurately perceive. Or in a complex environment, background noise may mask the details of the volume change, resulting in inaccurate positioning or even misjudgment. For example, in outdoor competitions, wind noise, traffic noise and the like may affect the hearing judgment of the participants. For the above reasons, the participants need to concentrate highly and repeatedly try to determine the position of the signal source, which affects the efficiency and experience of the competition.

[0047] The present application provides a wireless direction finder circuit.

[0048] Please refer to Figure 1 In an embodiment of the present application, the wireless direction finder includes an antenna for receiving a wireless signal emitted by a signal source; the wireless direction finder circuit includes:

[0049] a local oscillator signal input end for inputting a local oscillator signal;

[0050] a mixing and detection circuit 01, a first input end of the mixing and detection circuit 01 is connected with the antenna, and a second input end of the mixing and detection circuit 01 is connected with the local oscillator signal input end; the mixing and detection circuit 01 is used for outputting a corresponding mixed signal according to the wireless signal and the local oscillator signal;

[0051] a rectifier circuit 02, an input end of the rectifier circuit 02 is connected with a first output end of the mixing and detection circuit 01; the rectifier circuit 02 is used for rectifying the mixed signal into a first direct current signal output;

[0052] a main control circuit 03, a first input end of the main control circuit 03 is connected with an output end of the rectifier circuit 02, and the main control circuit 03 is used for outputting a variable sound control signal when the voltage value of the first direct current signal is greater than or equal to a preset voltage value;

[0053] a variable sound output circuit 04, a first input end of the variable sound output circuit 04 is connected with a second output end of the mixing and detection circuit 01, and a second input end of the variable sound output circuit 04 is connected with a first output end of the main control circuit 03; the variable sound output circuit 04 is used for outputting a corresponding first audio signal according to the mixed signal when no variable sound control signal is received, and outputting a corresponding second audio signal according to the variable sound control signal and the mixed signal when the variable sound control signal is received; wherein the frequency of the second audio signal is not equal to that of the first audio signal.

[0054] In the embodiment, the antenna can receive a wireless signal from a signal source. The mixing and detection circuit 01 can mix the received wireless signal with the local oscillator signal input from the local oscillator signal input terminal to generate a mixed signal. The rectifier circuit 02 can convert the mixed signal generated by the mixing and detection circuit 01 into a first direct current signal. The main control circuit 03 can output a variable tone control signal when the voltage value of the first direct current signal is greater than or equal to a preset voltage value. The variable tone output circuit 04 outputs a corresponding first audio signal according to the mixed signal when no variable tone control signal is received; outputs a corresponding second audio signal according to the variable tone control signal and the mixed signal when the variable tone control signal is received; wherein the frequency of the second audio signal is not equal to the frequency of the first audio signal. In this way, when the variable tone control signal is received, the variable tone output circuit 04 generates a second audio signal based on the variable tone control signal and the mixed signal, and the frequency of the second audio signal is different from the frequency of the first audio signal, which can prompt the user that the signal source has entered the preset distance range. In this way, the embodiment prompts the positioning information of the signal source through the tone and volume double prompt mechanism. Compared with the prior art, the embodiment can prompt that the signal source is in the key area range through the change of the tone, and even in the scene with large noise interference, the user can also clearly obtain the positioning information of the signal source through the change of the tone, thereby improving the positioning efficiency and the adaptability to the competition environment.

[0055] In a radio direction finding competition, the participants need to find a signal transmitter hidden in a certain area. The wireless direction finder of the embodiment can help the participants to locate the signal source more efficiently. In the initial stage, when the participants are far away from the signal source, the signal received by the wireless direction finder is weak, and the voltage of the first direct current signal converted from the corresponding mixed signal is lower than the preset voltage value. At this time, the first audio signal is output, such as a medium frequency tone, indicating that the participants are approaching but have not yet reached the key area. As the participants gradually approach the signal source, the received wireless signal is enhanced, resulting in an increase in the voltage value of the first direct current signal. Once the voltage value reaches or exceeds the preset voltage value, the main control circuit 03 outputs the variable tone control signal. At this time, the variable tone output circuit 04 starts to output the second audio signal, for example, a lower frequency tone mode, to tell the participants that they have approached the signal source. Compared with the prior art, the embodiment has a clear tone differentiation mechanism and can clearly prompt the user that he has entered the key area of the signal source.

[0056] In another radio direction-finding competition, the contestants need to distinguish the true and false of multiple signal transmitters. The wireless direction-finder of the embodiment can help the contestants to locate the true signal source more efficiently. When the contestant is far away from the true signal source, the signal received by the wireless direction-finder is weak, and the first direct current signal voltage converted by the mixed frequency signal is lower than the preset voltage value. At this time, the first audio signal is output, such as a medium frequency tone, indicating that the signal source is false. When the contestant is close to the true signal source, the signal received by the wireless direction-finder is strong, and the voltage value of the first direct current signal reaches or exceeds the preset voltage value, and the variable sound control signal is output by the main control circuit 03. At this time, the variable sound output circuit 04 starts to output the second audio signal, for example, a lower frequency tone mode, telling the contestant that the signal source in this direction is the true signal source. Compared with the prior art, the embodiment can simply distinguish the true and false signal sources, and the contestant will not be misled by the false signal source, wasting valuable time searching for the wrong direction.

[0057] In the present application, the antenna can receive wireless signals from the signal source. The mixing and detection circuit 01 can mix the received wireless signals with the local oscillator signal input into the local oscillator signal input end to generate a mixed frequency signal. The rectifier circuit 02 can convert the mixed frequency signal generated by the mixing and detection circuit 01 into a first direct current signal. The main control circuit 03 can output a variable sound control signal when the voltage value of the first direct current signal is greater than or equal to a preset voltage value. The variable sound output circuit 04 outputs the corresponding first audio signal according to the mixed frequency signal when it does not receive the variable sound control signal; outputs the corresponding second audio signal according to the variable sound control signal and the mixed frequency signal when it receives the variable sound control signal; wherein the frequency of the second audio signal is not equal to that of the first audio signal. In this way, when the variable sound control signal is received, the variable sound output circuit 04 generates a second audio signal based on the variable sound control signal and the mixed frequency signal, and the frequency of the second audio signal is different from that of the first audio signal, prompting the user that the signal source has entered the preset distance range. In this way, the application prompts the positioning information of the signal source through the tone and volume double prompt mechanism, and compared with the prior art, the application improves the positioning efficiency and the adaptability to the competition environment.

[0058] Please refer to Figure 3 In an embodiment of the present application, the variable sound output circuit 04 includes a first diode D301, a first capacitor C301, a second capacitor C302, a third capacitor C303, a fourth capacitor C304, a first resistor R301, a second resistor R302, a third resistor R303, a fourth resistor R304, a fifth resistor R305, a first triode Q301 and a power amplifier chip U1.

[0059] One end of the first resistor R301 is connected with the first output end Ton1 of the main control circuit 03, the other end of the first resistor R301 and one end of the second resistor R302 are connected with the base of the first triode Q301, the emitter of the first triode Q301 is grounded with the other end of the second resistor R302, the positive pole of the first diode D301 is connected with the first input end of the sound changing output circuit 04, the negative pole of the first diode D301, one end of the first capacitor C301 and one end of the third resistor R303 are connected with one end of the fourth resistor R304, the other end of the fourth resistor R304, the collector of the first triode Q301 and one end of the second capacitor C302 are connected with one end of the third capacitor C303, the other end of the first capacitor C301 and the other end of the second capacitor C302 are grounded with the other end of the third resistor R303, the other end of the third capacitor C303, one end of the fourth capacitor C304 and one end of the fifth resistor R305 are connected with the input end of the power amplifier chip U1, the fourth capacitor C304 and the other end of the fifth resistor R305 are grounded, and the output end of the power amplifier chip U1 is the output end of the sound changing output circuit 04.

[0060] In the embodiment, when the voltage value of the first direct current signal is less than the preset voltage value, the mixed frequency signal is filtered and directly input to the power amplifier chip U1, and the power amplifier chip U1 outputs the corresponding first audio signal according to the mixed frequency signal. When the voltage value of the first direct current signal is greater than or equal to the preset voltage value, the main control circuit 03 can output the PWM control signal to periodically control the turn-on / off of the first triode Q301. When the PWM signal is at high level, the triode is turned on and grounded, and the mixed frequency signal flows to the ground; when the PWM signal is at low level, the triode is turned off, and the mixed frequency signal is input to the power amplifier chip U1. The first diode D301, the first capacitor C301, the second capacitor C302, the third capacitor C303, the fourth capacitor C304, the first resistor R301, the second resistor R302, the third resistor R303, the fourth resistor R304 and the fifth resistor R305 can filter the mixed frequency signal. In this way, the embodiment can change the signal frequency input to the power amplifier chip U1 when the voltage value of the first direct current signal is greater than or equal to the preset voltage value, so as to realize the frequency division of the mixed frequency signal input to the power amplifier chip U1. In this way, the power amplifier chip U1 can output the corresponding second audio signal according to the input signal with the changed frequency.

[0061] Please refer to Figure 4 In an embodiment of the present application, the rectifier circuit 02 comprises the sixth resistor R401, the seventh resistor R402, the eighth resistor R403, the ninth resistor R404, the tenth resistor R405, the fifth capacitor C401, the sixth capacitor C402, the seventh capacitor C403 and the second diode D401.

[0062] One end of the sixth resistor R401 is connected with the power supply end of the rectifier circuit 02, the other end of the sixth resistor R401, one end of the seventh resistor R402 and one end of the fifth capacitor C401 are connected with the positive pole of the second diode D401, the negative pole of the second diode D401, one end of the sixth capacitor C402 and one end of the eighth resistor R403 are connected with one end of the ninth resistor R404, the other end of the seventh resistor R402, the other end of the eighth resistor R403 and the other end of the sixth capacitor C402 are grounded, the other end of the ninth resistor R404 and the other end of the seventh capacitor C403 are connected with the output end SMeter of the rectifier circuit 02, the other end of the fifth capacitor C401 is connected with one end of the tenth resistor R405, the other end of the tenth resistor R405 is connected with the input end SV2 of the rectifier circuit 02.

[0063] In the embodiment, the sixth resistor R401 and the seventh resistor R402 limit the current and divide the voltage of the power supply, the second diode D401 can input the signal to rectify and convert the signal into the first direct current signal, when the input signal is in the positive half cycle, the second diode D401 is forward conducting to allow the current to pass through, while in the negative half cycle, the second diode D401 is reverse cut-off to prevent the current from flowing, the sixth capacitor C402, the seventh capacitor C403, the eighth resistor R403 and the ninth resistor R404 can filter the first direct current signal after rectification.

[0064] Please refer to Figure 2 In an embodiment of the present application, the wireless direction finder circuit further comprises:

[0065] The signal amplification circuit 05 has a first input end connected with the antenna and an output end connected with the first input end of the mixing and detection circuit 01, and is configured to amplify the wireless signal output by the antenna and output to the mixing and detection circuit 01.

[0066] The gain adjustment circuit 06 has an output end connected with the second input end of the signal amplification circuit 05 and the third input end of the mixing and detection circuit 01 respectively, and is configured to output a corresponding gain adjustment voltage to adjust the amplification multiple of the signal amplification circuit 05 when triggered by a user.

[0067] The main control circuit 03 is configured to output the sound change control signal when the voltage value of the first direct current signal is greater than or equal to the product of the preset voltage value and the amplification multiple.

[0068] It should be noted that the farther the distance of the signal source, the weaker the signal received by the antenna, at which time the user can set a larger amplification factor through the gain adjustment circuit 06; the closer the distance of the signal source, the stronger the signal received by the antenna, at which time the user can set a smaller amplification factor through the gain adjustment circuit 06. In this way, the sound emitted by the sound conversion output circuit 04 can be within a relatively clear range, and will not be too small to be inaudible or too large to cause hearing damage.

[0069] It should be noted that the basis for determining whether the contestant has reached the key area is that when the distance between the contestant and the signal source is within a certain value, it means that the contestant has reached the key area. However, the adjustment of the amplification factor will cause the first direct current signal to also be amplified by the corresponding amplification factor, so in this embodiment, the variable sound control signal is output only when the voltage value of the first direct current signal is greater than or equal to the product of the preset voltage and the amplification factor, otherwise no output is performed.

[0070] Please refer to Figure 2 In an embodiment of the present application, the wireless direction finder circuit further comprises:

[0071] The display circuit 07 is connected to the second output end of the master control circuit 03.

[0072] The master control circuit 03 is further configured to control the display circuit 07 to display amplification factor information corresponding to the voltage value of the gain adjustment voltage according to the gain adjustment voltage, and to control the display circuit 07 to display signal strength information corresponding to the voltage value of the first direct current signal according to the first direct current signal.

[0073] It should be noted that in an embodiment, the master control circuit 03 is specifically configured to determine the number of signal bars corresponding to the first direct current signal according to the voltage value of the first direct current signal and a first preset mapping relationship; wherein the first preset mapping relationship is used to indicate the number of signal bars corresponding to different levels of voltage ranges; and to control the display of the display circuit 07 according to the amplification factor information and the number of signal bars.

[0074] In this embodiment, the signal strength information can be directly displayed by the number of signal bars. Assuming that the gain adjustment voltage is 22V, the amplification percentage is 100%; when the gain adjustment voltage is 4V, the amplification percentage is 10%. In the first preset mapping relationship, when the voltage value of the first direct current signal is greater than K*(N-1) and less than or equal to K*N, the number of signal bars can be determined as N; wherein K is the voltage interval of adjacent voltage levels, and N is a positive integer greater than or equal to 1. For example, K can be 0.33V, and when the voltage value of the first direct current signal is 3.3V, the number of signal bars is calculated to be 10. In a game scene, the farthest distance from the signal source is 10 kilometers, the amplification percentage is 100%, the number of signal bars is 1, and the signal source distance is indicated as 10 kilometers. At this time, the gain adjustment circuit 06 outputs a gain adjustment voltage of 22V and a first direct current signal of 0.33V. The user can calculate that the signal source distance is about 10 kilometers according to the amplification percentage of 100% and the number of signal bars of 1, and each increase of 1 bar indicates that the distance from the signal source is 1 kilometer closer. As the user approaches the signal source, the amplification percentage is 100%, the number of signal bars is 10, and the signal source distance is indicated as 1 kilometer. At this time, the gain adjustment circuit 06 outputs a gain adjustment voltage of 22V and a first direct current signal of 3.3V. The user can adjust the amplification percentage to 10% and display the number of signal bars to 1, which also indicates that the signal source distance is 1 kilometer. At this time, the gain adjustment circuit 06 outputs a gain adjustment voltage of 4V and a first direct current signal of 0.33V. The user can calculate that the signal source distance is about 1 kilometer according to the amplification percentage of 100% and the number of signal bars of 10, or according to the amplification percentage of 10% and the number of signal bars of 1. At this time, each increase of 1 bar indicates that the distance from the signal source is 0.1 kilometer closer. In this way, the user can adjust the appropriate amplification percentage during the process of searching for the signal source on the map, and then calculate the approximate distance of the signal source according to the distance information indicated by the number of signal bars under the amplification percentage, until the signal source is found.

[0075] Please refer to Figure 5 In an embodiment of the present application, the antenna includes a first antenna Ant1 and a second antenna Ant2, and the signal amplification circuit 05 includes a first transformer T501, a second transformer T502, a third transformer T503, a fourth transformer T504, an eighth capacitor C501, a ninth capacitor C502, a tenth capacitor C503, a first double-gate field effect transistor Q501, and a third diode D501.

[0076] The first antenna Ant1 is connected with the first primary end of the first transformer T501, the second primary end of the first transformer T501 is grounded, the second antenna Ant2 is connected with the first secondary end of the first transformer T501, the second secondary end of the first transformer T501 is connected with the first primary end of the second transformer T502, the second primary end of the second transformer T502 is grounded, the first secondary end of the second transformer T502 is connected with one end of the eighth capacitor C501, the second secondary end of the second transformer T502 is grounded with the other end of the eighth capacitor C501, the secondary common end of the second transformer T502 is connected with the first gate of the first double-gate field effect transistor Q501, the second gate of the first double-gate field effect transistor Q501 is connected with the power supply end of the signal amplification circuit 05, the source of the first double-gate field effect transistor Q501 is grounded, the drain of the first double-gate field effect transistor Q501 is connected with the primary common end of the third transformer T503, the first primary end of the third transformer T503 is connected with one end of the ninth capacitor C502, the second primary end of the third transformer T503 and the other end of the ninth capacitor C502 are connected with the negative electrode of the third diode D501, the positive electrode of the third diode D501 is connected with the output end of the gain adjustment circuit 06, the first secondary end of the third transformer T503 is connected with the first primary end of the fourth transformer T504, the second secondary end of the third transformer T503 is grounded with the second primary end of the fourth transformer T504, the first secondary end of the fourth transformer T504 is connected with one end of the tenth capacitor C503, the second secondary end of the fourth transformer T504 is grounded with the other end of the tenth capacitor C503, and the secondary common end of the fourth transformer T504 is connected with the input end of the mixing and detection circuit 01.

[0077] In this embodiment, the wireless signal received by the first antenna Ant1 is introduced into the primary winding of the first transformer T501, and there is a reference point relative to it, which helps to stabilize the received signal and reduce noise interference. The second antenna Ant2 is connected to the first secondary side of the first transformer T501, and the signals received by the two antennas are preliminarily compared, which can enhance the quality of wireless signal reception and improve the directivity. Then, the wireless signal is transmitted to the second transformer T502 for impedance matching and preliminary signal amplification. The first gate of the first double-gate field effect transistor Q501 receives the signal from the second transformer T502, and the second gate is connected to the power supply end for providing appropriate bias voltage, so that the first double-gate field effect transistor Q501 works in the amplification zone, thereby realizing effective amplification of the signal in cooperation with the third transformer T503. Among them, the third transformer T503 is connected to the negative electrode of the first diode D1, and the positive electrode of the first diode D1 is connected to the output end of the gain adjustment circuit 06, which can provide an amplified gain control input to dynamically control the degree of signal amplification according to the user's trigger instruction. After the above-mentioned signal is further filtered and smoothed by the fourth transformer T504, it is sent to the mixing and detection circuit 01. In this way, the wireless signal can be converted into a first electrical signal output, and the amplification multiple can be adjusted by the gain adjustment voltage of the gain adjustment circuit 06.

[0078] Please refer to Figure 6 In an embodiment of the present application, the gain adjustment circuit 06 includes a first adjustable resistor RV601, a second transistor Q601, a first switch circuit 61, a second switch circuit 62, an eleventh resistor R601, a twelfth resistor R602, a thirteenth resistor R603 and an eleventh capacitor C601.

[0079] The first end of the first adjustable resistor RV601, the power supply end of the gain adjustment circuit 06 and the collector of the second transistor Q601 are connected, the second end of the first adjustable resistor RV601 is grounded, the adjustment end of the first adjustable resistor RV601 is connected with the base of the second transistor Q601, the emitter of the second transistor Q601, the first end of the first switch circuit 61 and the first end of the second switch circuit 62 are connected, the second end of the second switch circuit 62 and one end of the thirteenth resistor R603 are connected, the other end of the thirteenth resistor R603, the second end of the first switch circuit 61, one end of the eleventh resistor R601 and the output end of the gain adjustment circuit 06 are connected, the other end of the eleventh resistor R601, one end of the twelfth resistor R602, one end of the eleventh capacitor C601 and the detection end of the gain adjustment circuit 06 are connected, the other end of the twelfth resistor R602 and the other end of the eleventh capacitor C601 are grounded, the controlled end of the first switch circuit 61 is connected with the first signal output end of the master control circuit 03, and the controlled end of the second switch circuit 62 is connected with the second signal output end of the master control circuit 03.

[0080] In this embodiment, the user can change the voltage applied to the base of the second transistor Q601 by adjusting the resistance of the first adjustable resistor RV601, thereby controlling the conduction state of the transistor, and then adjusting the output gain adjustment voltage. In addition, the user can also trigger the main control circuit 03 to switch the conduction state of the first switch circuit 61 (including resistors R604-R608, transistors Q602 and Q603) and the second switch circuit 62 (including resistors R609-R612, transistors Q604 and Q605), to realize the conversion between different amplification factors, suitable for different distances of the signal source. For example, when the first switch circuit 61 is turned on and the second switch circuit 62 is turned off, the adjustable amplification factor percentage of the first adjustable resistor RV601 at this time is 0-100%, suitable for wireless sports competition scenarios with a long distance signal source; when the second switch circuit 62 is turned on and the first switch circuit 61 is turned off, the adjustable amplification factor percentage of the first adjustable resistor RV601 at this time is 0-16%, suitable for wireless sports competition scenarios with a short distance signal source. Among them, because the thirteenth resistor R603 performs voltage division, the voltage passing through the second switch circuit 62 is low, so the output gain adjustment voltage is smaller, and the adjustable amplification factor is also smaller. In this embodiment, the resistance of the first adjustable resistor RV601 can be adjusted to change the voltage applied to the base of the second transistor Q601. The change of this voltage can affect the conduction degree of the second transistor Q601, so as to change the voltage output by the emitter, and then output through the first switch circuit 61 or the second switch circuit 62 and the thirteenth resistor R603. The eleventh resistor R601, the twelfth resistor R602 and the eleventh capacitor C601 constitute a detection feedback circuit, which can feed back the voltage value of the gain adjustment voltage to the main control circuit 03, and the main control circuit 03 can analyze the corresponding gain adjustment voltage, thereby calculating the amplification factor information and controlling the display circuit 07 to display.

[0081] Please refer to Figure 7 In an embodiment of the present application, the mixing and detection circuit 01 includes a second double-gate field effect transistor Q701, a third double-gate field effect transistor Q702, a fourth double-gate field effect transistor Q703, a fifth transformer T701, a twelfth capacitor C701, a thirteenth capacitor C702, a first crystal oscillator Y701, and an output amplification circuit 71.

[0082] The first gate of the second double-gate field effect transistor Q701, the local oscillator signal input terminal CLK_ADJ and the output terminal SV1 of the signal amplification circuit 05 are connected, the second gate of the second double-gate field effect transistor Q701, the second gate of the third double-gate field effect transistor Q702, the second gate of the fourth double-gate field effect transistor Q703 and the power supply terminal of the frequency mixing and detection circuit 01 are connected, the source of the second double-gate field effect transistor Q701, the source of the third double-gate field effect transistor Q702 and the source of the fourth double-gate field effect transistor Q703 are grounded, the drain of the second double-gate field effect transistor Q701 and one end of the twelfth capacitor C701 are connected with the first primary end of the fifth transformer T701, the second primary end of the fifth transformer T701 and the other end of the twelfth capacitor C701 are connected with the power supply terminal of the frequency mixing and detection circuit 01, the first secondary end of the fifth transformer T701 is grounded, the second secondary end of the fifth transformer T701 is connected with the first gate of the third double-gate field effect transistor Q702, the drain of the third double-gate field effect transistor Q702 and the output terminal of the gain adjustment circuit 06 are connected with the input terminal of the first crystal oscillator Y701, the ground terminal of the first crystal oscillator Y701 is grounded, the output terminal of the first crystal oscillator Y701 is connected with the first gate of the fourth double-gate field effect transistor Q703, the drain of the fourth double-gate field effect transistor Q703 and one end of the thirteenth capacitor C702 are connected with the output terminal of the gain adjustment circuit 06, the other end of the thirteenth capacitor C702 is connected with the input terminal of the output amplification circuit 71, and the output terminal of the output amplification circuit 71 is connected with the output terminal SV2 of the frequency mixing and detection circuit 01.

[0083] In the embodiment, the first electric signal amplified by the signal amplification circuit 05 and the local oscillator signal are introduced into the second double-gate field effect transistor Q701 for frequency mixing, the power supply terminal of the frequency mixing and detection circuit 01 provides necessary bias voltage, the mixed signal is subjected to impedance matching and amplification by the fifth transformer T701 and then output to the third double-gate field effect transistor Q702 for signal enhancement. The first crystal oscillator Y701 can provide stable and pure base frequency source, performs wave condensation on the mixed signal, and outputs intermediate frequency signal of specific frequency (such as 10.7MHz), and the output amplification circuit 71 outputs the signal after enhancement and amplification. The output amplification circuit 71 can include resistors R701-R705, capacitors C702-C704, transistors Q704 and Q705 and transformer T702, which jointly act on the signal for enhancement and amplification, so as to ensure that the output signal has sufficient strength and clarity.

[0084] Please refer to Figure 8 In an embodiment of the present application, the wireless direction finder circuit further comprises:

[0085] The local oscillator signal generating circuit 08, the controlled end of the local oscillator signal generating circuit 08 is connected with the third output end of the master control circuit 03, and the output end of the local oscillator signal generating circuit 08 is connected with the local oscillator signal input end; the local oscillator signal generating circuit 08 is used for outputting the local oscillator signal of the corresponding frequency according to the frequency control signal output by the master control circuit 03.

[0086] It should be noted that the local oscillator signal generating circuit 08 can include a frequency synthesizer U2, a clock circuit and a filter amplification circuit. The controlled end of the frequency synthesizer U2 is connected with the master control circuit 03, the first signal end of the frequency synthesizer U2 is connected with one end of the clock circuit, the second signal end of the frequency synthesizer U2 is connected with the other end of the clock circuit, the first output end of the frequency synthesizer U2 is connected with the first input end of the filter amplification circuit, the second output end of the frequency synthesizer U2 is connected with the second input end of the filter amplification circuit, and the output end of the filter amplification circuit is connected with the second input end of the mixing and detection circuit 01.

[0087] In the embodiment, the master control circuit 03 can output the frequency control signal, and the frequency synthesizer U2 can generate the local oscillator signal of different frequencies according to the frequency control signal and in cooperation with the clock circuit (including the resistance R812, the resistance R813, the capacitor C814, the capacitor C815, the crystal oscillator Y801 and the adjustable capacitor CV801), so as to adapt to the frequency range of different radio stations. The local oscillator signal is filtered and amplified by the filter amplification circuit (including the resistance R801~the resistance R814, the capacitor C801~the capacitor C813, the triode Q801, the triode Q802, the inductor L801 and the diode D803), and then output to the mixing and detection circuit 01 through the output end CLK_ADJ. In this way, the embodiment can remove the noise and unnecessary frequency components in the local oscillator signal, and ensure the quality of the output signal. The filtered local oscillator signal is amplified by the triode Q801 and the triode Q802, so as to ensure that the signal strength is strong enough for the subsequent mixing and detection circuit 01 to use.

[0088] The application also provides a wireless direction finder, which comprises an antenna and a wireless direction finder circuit, and the specific structure of the wireless direction finder circuit is referred to the above-mentioned embodiments. Since the wireless direction finder adopts all the technical solutions of the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here.

[0089] The above-mentioned is only an exemplary embodiment of the application, and does not limit the patent scope of the application. Any equivalent structural transformation made by referring to the content of the specification and drawings of the application, or direct / indirect application in other related technical fields is included in the patent protection scope of the application.

Claims

1. A wireless direction finder circuit, characterized by The wireless direction finder comprises an antenna for receiving wireless signals emitted by a signal source; the wireless direction finder circuit comprises: a local oscillator signal input end for inputting a local oscillator signal; a mixing and detection circuit, a first input end of the mixing and detection circuit being connected with the antenna, a second input end of the mixing and detection circuit being connected with the local oscillator signal input end; the mixing and detection circuit is used for outputting a corresponding mixing signal according to the wireless signal and the local oscillator signal; a rectifier circuit, an input end of the rectifier circuit being connected with a first output end of the mixing and detection circuit; the rectifier circuit is used for rectifying the mixing signal into a first direct current signal output; a main control circuit, a first input end of the main control circuit being connected with an output end of the rectifier circuit, the main control circuit being used for outputting a variable sound control signal when a voltage value of the first direct current signal is greater than or equal to a preset voltage value; a variable sound output circuit, a first input end of the variable sound output circuit being connected with a second output end of the mixing and detection circuit, a second input end of the variable sound output circuit being connected with a first output end of the main control circuit; the variable sound output circuit is used for outputting a corresponding first audio signal according to the mixing signal when the variable sound control signal is not received, and outputting a corresponding second audio signal according to the variable sound control signal and the mixing signal when the variable sound control signal is received; wherein the frequency of the second audio signal is not equal to the frequency of the first audio signal.

2. The wireless direction finder circuit of claim 1, wherein, The variable sound output circuit comprises a first diode, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first triode and a power amplifier chip; one end of the first resistor is connected with the first output end of the main control circuit, the other end of the first resistor and one end of the second resistor are connected with the base of the first triode, the emitter of the first triode is grounded, the anode of the first diode is connected with the first input end of the variable sound output circuit, the cathode of the first diode, one end of the first capacitor, one end of the third resistor and one end of the fourth resistor are connected, the other end of the fourth resistor, the collector of the first triode and one end of the second capacitor are connected with one end of the third capacitor, the other end of the first capacitor, the other end of the third resistor and the other end of the second capacitor are grounded, the other end of the third capacitor, one end of the fourth capacitor and one end of the fifth resistor are connected with the input end of the power amplifier chip, the fourth capacitor and the other end of the fifth resistor are grounded, and the output end of the power amplifier chip is the output end of the variable sound output circuit.

3. The wireless direction finder circuit of claim 1, wherein, The rectifier circuit comprises a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a fifth capacitor, a sixth capacitor, a seventh capacitor and a second diode; One end of the sixth resistor is connected with the power supply end of the rectifier circuit, the other end of the sixth resistor, one end of the seventh resistor and one end of the fifth capacitor are connected with the positive electrode of the second diode, the negative electrode of the second diode, one end of the sixth capacitor and one end of the eighth resistor are connected with one end of the ninth resistor, the other end of the seventh resistor, the other end of the eighth resistor and the other end of the sixth capacitor are grounded, the other end of the ninth resistor and the other end of the seventh capacitor are connected with the output end of the rectifier circuit, the other end of the fifth capacitor is connected with one end of the tenth resistor, and the other end of the tenth resistor is connected with the input end of the rectifier circuit.

4. The wireless direction finder circuit of claim 1, wherein, Further comprising: a signal amplification circuit, a first input end of the signal amplification circuit is connected with the antenna, and an output end of the signal amplification circuit is connected with a first input end of the mixed frequency detection circuit, the signal amplification circuit is used for amplifying the wireless signal output by the antenna and outputting the amplified wireless signal to the mixed frequency detection circuit; a gain adjustment circuit, output ends of the gain adjustment circuit are respectively connected with a second input end of the signal amplification circuit and a third input end of the mixed frequency detection circuit; the gain adjustment circuit is used for outputting a corresponding gain adjustment voltage to adjust the amplification multiple of the signal amplification circuit when being triggered by a user; the master control circuit is used for outputting a sound change control signal when the voltage value of the first direct current signal is greater than or equal to the product of the preset voltage value and the amplification multiple.

5. The wireless direction finder circuit of claim 4, wherein, Further comprising: a display circuit, a controlled end of the display circuit is connected with a second output end of the master control circuit; the master control circuit is further used for controlling the display circuit to display amplification multiple information corresponding to the voltage value of the gain adjustment voltage according to the gain adjustment voltage, and controlling the display circuit to display signal strength information corresponding to the voltage value of the first direct current signal according to the first direct current signal. the antenna comprises a first antenna and a second antenna, and the signal amplification circuit comprises a first transformer, a second transformer, a third transformer, a fourth transformer, an eighth capacitor, a ninth capacitor, a tenth capacitor, a first double-gate field effect transistor and a third diode; 6. The wireless direction finder circuit of claim 4, wherein, ​ The first antenna is connected with a first primary end of the first transformer, a second primary end of the first transformer is grounded, the second antenna is connected with a first secondary end of the first transformer, a second secondary end of the first transformer is connected with a first primary end of the second transformer, a second primary end of the second transformer is grounded, a first secondary end of the second transformer is connected with one end of the eighth capacitor, a second secondary end of the second transformer is grounded, a secondary common end of the second transformer is connected with a first gate of the first double-gate field effect transistor, a second gate of the first double-gate field effect transistor is connected with a power supply end of the signal amplification circuit, a source of the first double-gate field effect transistor is grounded, a drain of the first double-gate field effect transistor is connected with a primary common end of the third transformer, a first primary end of the third transformer is connected with one end of the ninth capacitor, a second primary end of the third transformer and the other end of the ninth capacitor are connected with a negative electrode of the third diode, a positive electrode of the third diode is connected with an output end of the gain adjustment circuit, a first secondary end of the third transformer is connected with a first primary end of the fourth transformer, a second secondary end of the third transformer is grounded, a first secondary end of the fourth transformer is connected with one end of the tenth capacitor, a second secondary end of the fourth transformer and the other end of the tenth capacitor are grounded, and a secondary common end of the fourth transformer is connected with an input end of the mixing and detection circuit.

7. The wireless direction finder circuit of claim 4, wherein, The gain adjustment circuit comprises a first adjustable resistor, a second triode, a first switch circuit, a second switch circuit, an eleventh resistor, a twelfth resistor, a thirteenth resistor and an eleventh capacitor. A first end of the first adjustable resistor, a power supply end of the gain adjustment circuit and a collector of the second triode are connected, a second end of the first adjustable resistor is grounded, an adjustment end of the first adjustable resistor is connected with a base of the second triode, an emitter of the second triode, a first end of the first switch circuit and a first end of the second switch circuit are connected, a second end of the second switch circuit is connected with one end of the thirteenth resistor, the other end of the thirteenth resistor, a second end of the first switch circuit and one end of the eleventh resistor are connected with an output end of the gain adjustment circuit, the other end of the eleventh resistor, one end of the twelfth resistor and one end of the eleventh capacitor are connected with a detection end of the gain adjustment circuit, the other end of the twelfth resistor and the other end of the eleventh capacitor are grounded, a controlled end of the first switch circuit is connected with a first signal output end of the master control circuit, and a controlled end of the second switch circuit is connected with a second signal output end of the master control circuit.

8. The wireless direction finder circuit of claim 4, wherein, The mixing and detection circuit comprises a second double-gate field effect transistor, a third double-gate field effect transistor, a fourth double-gate field effect transistor, a fifth transformer, a twelfth capacitor, a thirteenth capacitor, a first crystal oscillator and an output amplification circuit. The first gate of the second double-gate field effect transistor, the local oscillator signal input end and the output end of the signal amplification circuit are connected, the second gate of the second double-gate field effect transistor, the second gate of the third double-gate field effect transistor, the second gate of the fourth double-gate field effect transistor and the power supply end of the frequency mixing and detection circuit are connected, the source of the second double-gate field effect transistor, the source of the third double-gate field effect transistor and the source of the fourth double-gate field effect transistor are grounded, the drain of the second double-gate field effect transistor and one end of the twelfth capacitor are connected with the first primary end of the fifth transformer, the second primary end of the fifth transformer and the other end of the twelfth capacitor are connected with the power supply end of the frequency mixing and detection circuit, the first secondary end of the fifth transformer is grounded, the second secondary end of the fifth transformer is connected with the first gate of the third double-gate field effect transistor, the drain of the third double-gate field effect transistor and the output end of the gain adjustment circuit are connected with the input end of the first crystal oscillator, the ground end of the first crystal oscillator is grounded, the output end of the first crystal oscillator is connected with the first gate of the fourth double-gate field effect transistor, the drain of the fourth double-gate field effect transistor and one end of the thirteenth capacitor are connected with the output end of the gain adjustment circuit, the other end of the thirteenth capacitor is connected with the input end of the output amplification circuit, and the output end of the output amplification circuit is connected with the output end of the frequency mixing and detection circuit.

9. The wireless direction finder circuit of claim 1, wherein, Further comprising: The local oscillator signal generation circuit is connected with the third output end of the main control circuit at the controlled end, and the output end of the local oscillator signal generation circuit is connected with the local oscillator signal input end; the local oscillator signal generation circuit is used for outputting the local oscillator signal of the corresponding frequency according to the frequency control signal output by the main control circuit.

10. A wireless direction finder, characterized by The wireless direction finder comprises an antenna and the wireless direction finder circuit according to any one of claims 1 to 9.

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