Transmitting power control device of anti-recording equipment
By combining a microphone pickup, audio amplification, voltage comparison, and power selection module, the problem of the non-adjustable transmission power of the recording interference jammer is solved, and the ultrasonic power is automatically adjusted according to the distance of the sound source, reducing harm to the human body and operating costs.
Patent Information
- Application Number
- CN202422817804.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-19
- Publication Date
- 2025-10-17
- Estimated Expiration
- 2034-11-19
AI Technical Summary
The transmission power of existing recording jammers is not adjustable, which increases operating costs and may pose a health hazard if used for a long time.
Design a power control device for anti-recording equipment. Through a combination of a microphone pickup module, an audio amplification module, a voltage comparator module, an encoding conversion module, and a power selection module, the ultrasonic transmission power is automatically adjusted according to the distance of the sound source.
It achieves adaptive adjustment of ultrasonic power, avoiding the harm to the human body caused by emitting excessive power for a long time, and reducing operating costs.
Smart Images
Figure CN223450560U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to the technical field of speech signal processing, especially relates to a transmitting power control device of anti-recording equipment. BACKGROUND
[0002] The recording shield is applicable to various scenes: confidential occasions to ensure the safety of secrets, business occasions to maintain business secrets, personal privacy protection to prevent recording, public and sensitive places to create a safe conversation environment, and special areas to reduce the risk of voice leakage. When some recording interference shielding devices are used, the transmitting power cannot be adjusted, and the following disadvantages exist:
[0003] 1. The unadjustable power increases the operating cost when used for a long time.
[0004] 2. Long-time emission of strong and excessively large ultrasonic waves can cause certain harm to the human body.
[0005] Therefore, the anti-recording interference shielding instrument preferably can automatically adjust the transmitting power according to the interference distance. INVENTION CONTENT
[0006] The utility model discloses a kind of transmitting power control devices of anti-recording equipment, and specific technical solutions are as follows:
[0007] A kind of transmitting power control device of anti-recording equipment, including microphone pickup module, audio amplification module, voltage comparator module, encoding conversion module, power supply selection module connected in sequence;
[0008] The microphone pickup module is used to collect the voice signal outside the anti-recording equipment, and the collected voice signal is transmitted to the audio amplification module;
[0009] The audio amplification module is used to audio amplify the collected voice signal, and the amplified voice signal is transmitted to the voltage comparator module;
[0010] The voltage comparator module is used to judge the size relation of the voltage value of amplified voice signal and preset voltage value, and output judging result, and the judging result is transmitted to the encoding conversion module;
[0011] The encoding conversion module is used to encode according to judging result, and the encoding result is transmitted to the power supply selection module;
[0012] The power supply selection module is used to select the corresponding DC / DC module work according to the encoding result.
[0013] Preferably, it further includes filter module, and the filter module is connected with microphone pickup module and audio amplification module respectively.
[0014] Preferably, the audio amplification module comprises an LM386 power amplifier chip; the output end of the microphone pickup module is connected with the third pin of the LM386 power amplifier chip, the second pin and the fourth pin of the LM386 power amplifier chip are grounded respectively; the first pin of the LM386 power amplifier chip is connected with the eighth pin through the resistor R1 and the capacitor C1; the seventh pin of the LM386 power amplifier chip is grounded through the capacitor C2, the sixth pin of the LM386 power amplifier chip is connected with the power supply VCC, the fifth pin of the LM386 power amplifier chip is connected with the anode of the diode D1, the cathode of the diode D1 is connected with the voltage comparator module and one end of the capacitor C5 respectively, the other end of the capacitor C5 is grounded through the resistor R3.
[0015] Preferably, the voltage comparator module comprises a comparator U2 chip, a comparator U3 chip and a comparator U4 chip; the comparator U2 chip, the comparator U3 chip and the comparator U4 chip all adopt an LM393 comparator chip.
[0016] The output end of the audio amplification module is connected with the positive input end of the comparator U2 chip, the comparator U3 chip and the comparator U4 chip respectively.
[0017] The inverting input end of the comparator U2 chip is connected with the power supply through the resistor R2, and the inverting input end of the comparator U2 chip is grounded through the resistor R7; the output end of the comparator U2 chip is connected with the power supply through the resistor R6.
[0018] The inverting input end of the comparator U3 chip is connected with the power supply through the resistor R4, and the inverting input end of the comparator U3 chip is grounded through the resistor R9; the output end of the comparator U3 chip is connected with the power supply through the resistor R8.
[0019] The inverting input end of the comparator U4 chip is connected with the power supply through the resistor R5, and the inverting input end of the comparator U4 chip is grounded through the resistor R11; the output end of the comparator U4 chip is connected with the power supply through the resistor R10.
[0020] The reference voltages of the inverting input ends of the comparator U2 chip, the comparator U3 chip and the comparator U4 chip are sequentially increased.
[0021] Preferably, the encoding conversion module comprises a 74LS138 encoding chip.
[0022] Preferably, the power supply selection module comprises three DC-DC modules, which are a first DC-DC module, a second DC-DC module and a third DC-DC module respectively; the three DC-DC modules are connected with the output end of the encoding conversion module respectively; the voltages output by the three DC-DC modules are different.
[0023] Preferably, the three DC-DC modules respectively comprise CN3903 voltage conversion chips.
[0024] Compared with the prior art, the utility model has the following beneficial effects:
[0025] The transmitting power control device of the anti-recording equipment can be connected with the ultrasonic wave transmitting module of the anti-recording equipment, and comprises a microphone pickup module, an audio amplification module, a voltage comparator module, an encoding conversion module and a power supply selection module connected in sequence.The utility model first collects the voltage value of the input voice signal through the microphone pickup module, and amplifies the voice signal through the audio amplification module; the voltage comparator module judges the distance between the sound source (i.e. the position of the person) and the position of the anti-recording equipment according to the voltage value of the voice signal, and inputs the judgment result into the encoding conversion module; the encoding conversion module encodes, and the power supply selection module selects the output voltage of different power supplies according to the corresponding sound source position of the encoding; if the distance is far, a large power supply is selected for output, and if the distance is short, a small power supply is selected for output.The utility model judges the distance between the sound source and the anti-recording equipment according to the size of the input voice signal, and realizes the output of ultrasonic waves of different sizes according to the distance between the sound source and the anti-recording equipment, so that the power of the ultrasonic waves can be adjusted according to the distance between the sound source and the anti-recording equipment, avoiding the harm to the human body caused by long-time emission of ultrasonic waves with a large range. BRIEF DESCRIPTION OF DRAWINGS
[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. In all the drawings, similar elements or parts are generally identified by similar reference signs. In the drawings, each element or part is not necessarily drawn according to the actual proportion.
[0027] Figure 1 is the principle schematic diagram of the utility model.
[0028] Figure 2 is the application principle schematic diagram of the utility model.
[0029] Figure 3 is the circuit principle diagram of the microphone pickup module, the filter module and the audio amplification module of the utility model.
[0030] Figure 4 is the circuit principle diagram of the voltage comparator module.
[0031] Figure 5 is the circuit principle diagram of the encoding conversion module.
[0032] Figure 6 is the circuit principle diagram of the power supply selection module. DETAILED DESCRIPTION
[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0034] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "top", "bottom", "top surface", "bottom surface", "inside", "outside", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.
[0035] In the description of this utility model, "several" means one or more, "more" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The terms "first," "second," and "third" are used solely for descriptive purposes and to distinguish technical features, and are not to be construed as indicating or implying relative importance, or implicitly specifying the number or order of the technical features indicated.
[0036] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," "connected," and "set" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium, or they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances. The following describes an embodiment of the present invention based on its overall structure.
[0037] Example 1
[0038] like Figure 1 As shown, this embodiment provides a transmission power control device for an anti-recording device, including a microphone pickup module, a filter module, an audio amplification module, a voltage comparator module, a coding conversion module, and a power selection module connected in sequence.
[0039] The microphone pickup module is used for collecting voice signals outside the anti-recording device and transmitting the collected voice signals to the audio amplification module.
[0040] The audio amplification module is used for audio amplification of the collected voice signals and transmitting the amplified voice signals to the voltage comparator module.
[0041] The voltage comparator module is used for judging the size relationship between the voltage value of the amplified voice signals and the preset voltage value, outputting the judgment result, and transmitting the judgment result to the encoding conversion module.
[0042] The encoding conversion module is used for encoding according to the judgment result and transmitting the encoding result to the power supply selection module.
[0043] The power supply selection module is used for selecting the working of the corresponding DC / DC module according to the encoding result.
[0044] As shown in Figure 2 The anti-recording device transmitting power control device can be used with the ultrasonic wave transmitting module of the anti-recording device, which comprises microphone pickup module, audio amplification module, voltage comparator module, encoding conversion module and power supply selection module connected in sequence. The voltage value of the input voice signal is collected by the microphone pickup module, and the voice signal is amplified by the audio amplification module. The voltage comparator module judges the distance between the sound source (i.e. the position of the person) and the position of the anti-recording device according to the voltage value of the voice signal, and inputs the judgment result into the encoding conversion module. The encoding conversion module encodes, and the power supply selection module selects the output voltage of different power supplies according to the encoding of the sound source position. If the distance is far, the large power output is selected, and if the distance is near, the small power output is selected. The present application judges the distance between the sound source and the anti-recording device according to the size of the input voice signal, and realizes the output of ultrasonic wave with different power voltage according to the distance between the sound source and the anti-recording device, so as to realize the adjustment of the power of ultrasonic wave according to the distance between the sound source and the anti-recording device, and avoid the harm of long-time emission of strong ultrasonic wave with large range to human body.
[0045] As a preferred embodiment of the present embodiment, as shown in Figure 3 MK1 is a microphone pickup module for collecting original voice signals. The filter module comprises a high-frequency filter capacitor C4, one end of the microphone pickup module, i.e. the output end, is connected with the high-frequency filter capacitor C4 and one end of the capacitor C3 respectively, and the other end of the microphone pickup module and the other end of the high-frequency filter capacitor C4 are grounded.
[0046] The audio amplification module comprises an LM386 power amplifier chip; one end of a capacitor C3 is connected with a third pin of the LM386 power amplifier chip, a second pin and a fourth pin of the LM386 power amplifier chip are grounded respectively; a first pin of the LM386 power amplifier chip is connected with an eighth pin through a resistor R1 and a capacitor C1; a seventh pin of the LM386 power amplifier chip is grounded through a capacitor C2, a sixth pin of the LM386 power amplifier chip is connected with a power supply VCC, a fifth pin of the LM386 power amplifier chip is connected with an anode of a diode D1, a cathode of the diode D1 is connected with the voltage comparator module and one end of a capacitor C5 respectively, and the other end of the capacitor C5 is grounded through a resistor R3. The resistor R1 and the capacitor C1 constitute an integration circuit, which is used for adjusting an amplification multiple of the audio amplification module LM386.
[0047] As a preferred embodiment of the present embodiment, as shown in Figure 4 The voltage comparator module comprises a comparator U2 chip, a comparator U3 chip and a comparator U4 chip; the comparator U2 chip, the comparator U3 chip and the comparator U4 chip all adopt LM393 comparator chips.
[0048] The output end of the audio amplification module is connected with positive input ends of the comparator U2 chip, the comparator U3 chip and the comparator U4 chip respectively; positive power supply ends of the comparator U2 chip, the comparator U3 chip and the comparator U4 chip are connected with a power supply respectively, the power supply outputs a 5V voltage, and negative power supply ends of the comparator U2 chip, the comparator U3 chip and the comparator U4 chip are grounded respectively.
[0049] The inverse input end of the comparator U2 chip is connected with the power supply through a resistor R2, and the inverse input end of the comparator U2 chip is grounded through a resistor R7; the output end of the comparator U2 chip is connected with the power supply through a resistor R6.
[0050] The inverse input end of the comparator U3 chip is connected with the power supply through a resistor R4, and the inverse input end of the comparator U3 chip is grounded through a resistor R9; the output end of the comparator U3 chip is connected with the power supply through a resistor R8.
[0051] The inverse input end of the comparator U4 chip is connected with the power supply through a resistor R5, and the inverse input end of the comparator U4 chip is grounded through a resistor R11; the output end of the comparator U4 chip is connected with the power supply through a resistor R10.
[0052] The reference voltages of the inverse input ends of the comparator U2 chip, the comparator U3 chip and the comparator U4 chip are sequentially increased.
[0053] In the present embodiment, the reference voltage U ref1 of the comparator U2 chip is calculated as follows:
[0054] In the embodiment, the reference voltage U ref1 is 1V.
[0055] In the embodiment, the reference voltage U ref2 of the comparator U3 chip is calculated as follows:
[0056] In the embodiment, the reference voltage U ref2 is 2V.
[0057] In the embodiment, the reference voltage U ref3 of the comparator U4 chip is calculated as follows:
[0058] In the embodiment, the reference voltage U ref3 is 3V.
[0059] The voltage comparator module perceives the distance of the sound source by comparing the outputs of the comparator U2 chip, the comparator U3 chip and the comparator U4 chip, and the specific output results are shown in Table 1 as follows:
[0060] Table 1 Output table of the voltage comparator module
[0061] U2 output (Ctrl 1) U3 output (Ctrl 2) U4 output (Ctrl 3) Audio signal Sound source distance 5V 5V 5V Greater than or equal to 3V Close distance 5V 5V 0V Greater than or equal to 2V and less than 3V Medium distance 5V 0 0 Greater than or equal to 1V and less than 2V Far distance 0V 0V 0V Less than 1V Farthest distance
[0062] That is, when the output of the comparator U2 chip is 5V, the output of the comparator U3 chip is 5V, and the output of the comparator U4 chip is 5V, it indicates that the voice signal voltage output by the audio amplification module is greater than or equal to 3V, and it indicates that the position of the sound source (i.e. the position of the person) is close to the position of the anti-recording device.
[0063] When the output of the comparator U2 chip is 5V, the output of the comparator U3 chip is 5V, and the output of the comparator U4 chip is 0V, it indicates that the voice signal voltage output by the audio amplification module is greater than or equal to 2V and less than 3V, and it indicates that the position of the sound source (i.e. the position of the person) is medium distance from the position of the anti-recording device.
[0064] When the output of the comparator U2 chip is 5V, the output of the comparator U3 chip is 0V, and the output of the comparator U4 chip is 0V, it indicates that the voice signal voltage output by the audio amplification module is greater than or equal to 1V and less than 2V, and it indicates that the position of the sound source (i.e. the position of the person) is far from the position of the anti-recording device.
[0065] When the output of the comparator U2 chip is 0V, the output of the comparator U3 chip is 0V, and the output of the comparator U4 chip is 0V, it indicates that the voice signal voltage output by the audio amplification module is less than 1V, and it indicates that the position of the sound source (i.e. the position of the person) is the farthest from the position of the anti-recording device.
[0066] As a preferred embodiment of the embodiment, asFigure 5 As shown in the figure, the encoding conversion module includes a 74LS138 encoding chip. The pin A, pin B and pin C of the 74LS138 encoding chip are connected with the output terminals of the comparator U2 chip, the comparator U3 chip and the comparator U4 chip respectively. The 74LS138 encoding chip encodes the output signals of the comparator U2 chip, the comparator U3 chip and the comparator U4 chip, and the encoding result is used for the power supply selection module to select the corresponding DC-DC module to be turned on, so as to ensure that only one power supply module is turned on at a certain moment.
[0067] As a preferred embodiment of the present embodiment, as shown in the figure, Figure 6 As shown in the figure, the power supply selection module includes three DC-DC modules, which are a first DC-DC module, a second DC-DC module and a third DC-DC module respectively. The three DC-DC modules are connected with the output terminals of the encoding conversion module respectively. The voltages output by the three DC-DC modules are different from each other. The 74LS138 encoding chip has three output terminals, which are connected with the input terminals of the first DC-DC module, the second DC-DC module and the third DC-DC module respectively.
[0068] Specifically, as shown in the figure, Figure 6 As shown in the figure, the three DC-DC modules respectively include CN3903 voltage conversion chips.
[0069] The second pin of the CN3903 chip U6 of the first DC-DC module is connected with a power supply, the power supply outputs a 12V voltage, the seventh pin is connected with the first output terminal DC-DC1 of the 74LS138 encoding chip, the ninth pin and the fourth pin are grounded respectively, the eighth pin is grounded through the resistor R15, the first pin is connected with the third pin through the capacitor C6, the sixth pin is grounded through the capacitor C7 and the resistor R12, the third pin is connected with one end of the inductor L1, the other end of the inductor L1 is connected with one end of the capacitor C9, one end of the capacitor C8 and one end of the resistor R13 respectively, the other end of the capacitor C9 is grounded, the other end of the capacitor C8 and the other end of the resistor R13 are connected with one end of the resistor R14 respectively, and the other end of the resistor R14 is grounded.
[0070] The voltage output by the CN3903 chip U6 is:
[0071]
[0072] The CN3903 chip U6 is controlled by the DC-DC1 signal of the first output terminal of the 74LS138 encoding chip, and outputs a voltage when the DC-DC1 signal is at a high level. Among them, 0.925 is a reference voltage value generated inside the CN3903 chip.
[0073] The 2nd pin of the CN3903 chip U7 of the second DC-DC module is connected with a power supply, the power supply outputs 12V voltage, the 7th pin is connected with the second output end DC-DC2 of the 74LS138 encoding chip, the 9th pin and the 4th pin are grounded respectively, the 8th pin is grounded through the resistor R19, the 1st pin is connected with the 3rd pin through the capacitor C10, the 6th pin is grounded through the capacitor C11 and the resistor R16, the 3rd pin is connected with one end of the inductor L2, the other end of the inductor L2 is connected with one end of the capacitor C13, one end of the capacitor C12 and one end of the resistor R17 respectively, the other end of the capacitor C13 is grounded, the other end of the capacitor C12 and the other end of the resistor R17 are connected with one end of the resistor R18 respectively, and the other end of the resistor R18 is grounded.
[0074] The voltage output by the CN3903 chip U7 is:
[0075]
[0076] The CN3903 chip U7 is controlled by the DC-DC2 signal of the second output end of the 74LS138 encoding chip, and the voltage is output when the DC-DC2 signal is at a high level.
[0077] The 2nd pin of the CN3903 chip U8 of the third DC-DC module is connected with a power supply, the power supply outputs 12V voltage, the 7th pin is connected with the third output end DC-DC3 of the 74LS138 encoding chip, the 9th pin and the 4th pin are grounded respectively, the 8th pin is grounded through the resistor R23, the 1st pin is connected with the 3rd pin through the capacitor C14, the 6th pin is grounded through the capacitor C15 and the resistor R20, the 3rd pin is connected with one end of the inductor L3, the other end of the inductor L3 is connected with one end of the capacitor C17, one end of the capacitor C16 and one end of the resistor R21 respectively, the other end of the capacitor C17 is grounded, the other end of the capacitor C16 and the other end of the resistor R21 are connected with one end of the resistor R22 respectively, and the other end of the resistor R22 is grounded.
[0078] The voltage output by the CN3903 chip U7 is:
[0079]
[0080] The CN3903 chip U8 is controlled by the DC-DC3 signal of the third output end of the 74LS138 encoding chip, and the voltage is output when the DC-DC3 signal is at a high level.
[0081] The power supply selection module can obtain different output voltages according to different voltage output control signals of the encoding conversion module, so that the emissivity is adaptively adjusted.
[0082] The voltage output comprehensive table of the utility model is obtained as follows, as shown in Table 2:
[0083] Table 2 Voltage output comprehensive table
[0084]
[0085] Next, the working principle of this embodiment is described in detail to enable those skilled in the art to better understand the present invention:
[0086] When the comparator U2 chip outputs 5V, the comparator U3 chip outputs 5V, and the comparator U4 chip outputs 5V, the audio amplifier module outputs a voice signal voltage greater than or equal to 3V, indicating that the sound source (i.e., the person's location) is close to the anti-recording device. The DC-DC1 signal output by the transcoding module is high, while the DC-DC2 and DC-DC3 signals are low. The power selection module then turns on the first DC-DC module, outputting a 3V voltage for transmitting ultrasonic waves.
[0087] When the comparator U2 chip output is 5V, the comparator U3 chip output is 5V, and the comparator U4 chip output is 0V, it indicates that the voice signal voltage output by the audio amplifier module is greater than or equal to 2V and less than 3V, indicating that the sound source (i.e., the person's location) is within the distance of the anti-recording device. The DC-DC2 signal output by the transcoding module is high, while the DC-DC1 and DC-DC3 signals are low. The power selection module then turns on the second DC-DC module, outputting a 6V voltage for transmitting ultrasonic waves.
[0088] When comparator U2 outputs 5V, comparator U3 outputs 0V, and comparator U4 outputs 0V, the audio amplifier module outputs a voice signal voltage greater than or equal to 1V and less than 2V, indicating that the sound source (i.e., the person's location) is far from the anti-recording device. The DC-DC3 signal output by the transcoding module is high, while the DC-DC1 and DC-DC2 signals are low. The power selection module then turns on the third DC-DC module, generating a 9V output voltage for ultrasonic transmission.
[0089] When the output of comparator U2, comparator U3, and comparator U4 is 0V, the audio signal voltage output by the audio amplifier module is less than 1V, indicating that the sound source (i.e., the person's location) is the farthest from the anti-recording device. The DC-DC1, DC-DC2, and DC-DC3 signals output by the transcoding module are all low levels, and the 12V voltage from the anti-recording device's power adapter is directly used to transmit ultrasonic waves.
[0090] The foregoing description of the specific exemplary embodiments of the present application is for the purpose of illustrating and describing, rather than limiting the application, and it will be apparent to those of ordinary skill in the art that many changes and modifications can be made to the embodiments with the foregoing teaching, notwithstanding what can be suggested above and although only a few of the exemplary embodiments of the present application have been described. Although the embodiments of the present application have been described, the specific embodiments are merely illustrative of the present application and are not intended to limit the present application, and the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner, and the exemplary embodiments are selected and described for the purpose of explaining the specific principles of the present application and its practical application, so that those skilled in the art can make modifications, replacements, variations and various different selections and changes to the embodiments without creative contribution after reading the specification, as long as they are within the scope of the claims of the present application.
Claims
1. A transmission power control device for an anti-recording device, characterized in that: It includes a microphone pickup module, an audio amplifier module, a voltage comparator module, a code conversion module, and a power selection module connected in sequence; The microphone pickup module is used to collect voice signals outside the anti-recording device and transmit the collected voice signals to the audio amplification module; The audio amplification module is used to amplify the collected voice signal and transmit the amplified voice signal to the voltage comparator module; The voltage comparator module is used to determine the magnitude relationship between the voltage value of the amplified voice signal and the preset voltage value, output the determination result, and transmit the determination result to the encoding conversion module; The encoding conversion module is used to encode according to the judgment result and transmit the encoding result to the power selection module; The power selection module is used to select and control the operation of the corresponding DC / DC module according to the encoding result.
2. The transmission power control device for anti-recording equipment according to claim 1, characterized in that: It also includes a filtering module, which is connected to the microphone pickup module and the audio amplification module respectively.
3. The transmission power control device for anti-recording equipment according to claim 1, characterized in that: The audio amplifier module includes an LM386 power amplifier chip; the output end of the microphone pickup module is connected to the third pin of the LM386 power amplifier chip, and the second and fourth pins of the LM386 power amplifier chip are grounded respectively; the first pin of the LM386 power amplifier chip is connected to the eighth pin through a resistor R1 and a capacitor C1; the seventh pin of the LM386 power amplifier chip is grounded through a capacitor C2, the sixth pin of the LM386 power amplifier chip is connected to a power supply VCC, the fifth pin of the LM386 power amplifier chip is connected to the anode of a diode D1, the cathode of the diode D1 is connected to the voltage comparator module and one end of a capacitor C5 respectively, and the other end of the capacitor C5 is grounded through a resistor R3.
4. The transmission power control device for anti-recording equipment according to claim 1, characterized in that: The voltage comparator module includes a comparator U2 chip, a comparator U3 chip, and a comparator U4 chip; the comparator U2 chip, the comparator U3 chip, and the comparator U4 chip all use LM393 comparator chips; The output end of the audio amplifier module is connected to the non-inverting input end of the comparator U2 chip, the comparator U3 chip, and the comparator U4 chip respectively; The inverting input terminal of the comparator U2 chip is connected to the power supply through the resistor R2, and the inverting input terminal of the comparator U2 chip is grounded through the resistor R7; the output terminal of the comparator U2 chip is connected to the power supply through the resistor R6; The inverting input terminal of the comparator U3 chip is connected to the power supply through the resistor R4, and the inverting input terminal of the comparator U3 chip is grounded through the resistor R9; the output terminal of the comparator U3 chip is connected to the power supply through the resistor R8; The inverting input terminal of the comparator U4 chip is connected to the power supply through the resistor R5, and the inverting input terminal of the comparator U4 chip is grounded through the resistor R11; the output terminal of the comparator U4 chip is connected to the power supply through the resistor R10; The reference voltages of the inverting input terminals of the comparator U2 chip, the comparator U3 chip, and the comparator U4 chip increase in sequence.
5. The transmission power control device for anti-recording equipment according to claim 1, characterized in that: The encoding conversion module includes a 74LS138 encoding chip.
6. The transmission power control device for anti-recording equipment according to claim 1, characterized in that: The power selection module includes three DC-DC modules, namely a first DC-DC module, a second DC-DC module, and a third DC-DC module; the three DC-DC modules are respectively connected to the output end of the encoding conversion module; and the voltages output by the three DC-DC modules are different.
7. The transmission power control device for anti-recording equipment according to claim 6, characterized in that: The three DC-DC modules each include a CN3903 voltage conversion chip.