Anti-recording shielding instrument power amplifier transmitting device

Abstract

The utility model discloses an anti-recording shielding instrument power amplifier transmitting device, which comprises a single chip microcomputer, an MOS (metal oxide semiconductor) tube driving circuit, an MOS tube switching circuit, a sampling resistor, a current amplifying circuit and a power supply module, and is characterized in that two input ends of the MOS tube driving circuit are electrically connected with two output ends of the single chip microcomputer respectively; two output ends of the single chip microcomputer respectively output an ultrasonic control signal with the frequency of 40KHz and an ultrasonic control signal with the frequency of 25KHz; the MOS tube switching circuit comprises a first MOS tube switching circuit and a second MOS tube switching circuit; the first MOS tube switching circuit comprises a first MOS tube and a 40KHz ultrasonic transmitter, the grid electrode of the first MOS tube is electrically connected with the output end of the MOS tube driving circuit, the drain electrode of the first MOS tube is electrically connected with the power supply module, and the source electrode of the first MOS tube is electrically connected with the positive electrode of the power supply end of the 40KHz ultrasonic transmitter. According to the utility model, the MOS tube switching circuit is utilized to increase the transmitting power of the shielding instrument and enlarge the shielding distance; and meanwhile, a dual-frequency interference technology is adopted, so that the anti-recording effect is enhanced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to information security technical field, especially is involved in a kind of anti-recording shielding instrument power amplifier transmitting device. BACKGROUND

[0002] In commercial meeting and important occasion, sometimes need to utilize anti-recording interference shielding instrument to interfere with the recording function of recording equipment (such as mobile phone, recording pen), to prevent important information from leaking out.The effective shielding distance of anti-recording interference shielding instrument is proportional to transmitting power, the greater transmitting power, the farther effective shielding distance.Currently anti-recording interference shielding instrument has the following shortcomings:

[0003] 1, transmitting power is small, shielding distance is short;

[0004] 2, interference noise is single, shielding effect is not good. INVENTION CONTENT

[0005] The utility model solves the technical problem to provide a kind of anti-recording shielding instrument power amplifier transmitting device, utilize MOS tube switch circuit to increase the transmitting power of shielding instrument, expand shielding distance;While using double-frequency interference technology, enhance the effect of anti-recording.

[0006] To solve the above technical problem, the utility model adopts the following technical scheme:

[0007] The utility model relates to an anti -recording shield instrument power amplifier emission device, including single -chip microcomputer, MOS pipe drive circuit, MOS pipe switch circuit, sampling resistance, current amplification circuit and power module, wherein, two input ends of MOS pipe drive circuit are connected with two output ends of single -chip microcomputer electricity respectively, and two output ends of single -chip microcomputer respectively output the ultrasonic wave control signal of frequency 40KHz and the ultrasonic wave control signal of frequency 25KHz, MOS pipe switch circuit includes first MOS pipe switch circuit and second MOS pipe switch circuit, first MOS pipe switch circuit includes first MOS pipe and 40KHz ultrasonic wave emitter, and the grid of first MOS pipe is connected with the output of MOS pipe drive circuit electricity, and the drain of first MOS pipe is connected with power module electricity, and the source of first MOS pipe is connected with the power supply end positive pole of 40KHz ultrasonic wave emitter electricity, second MOS pipe switch circuit includes second MOS pipe and 25KHz ultrasonic wave emitter, and the grid of second MOS pipe is connected with the output of MOS pipe drive circuit electricity, and the drain of second MOS pipe is connected with the power supply end negative pole of 25KHz ultrasonic wave emitter electricity, and the power supply end positive pole of 25KHz ultrasonic wave emitter is connected with power module electricity, sampling resistance includes first sampling resistance and second sampling resistance, and one end of first sampling resistance is connected with the power supply end negative pole of 40KHz ultrasonic wave emitter electricity, and the other end is connected with GND end electricity, and one end of second sampling resistance is connected with the source of second MOS pipe electricity, and the other end is connected with GND end electricity, and the input of current amplification circuit is connected with the power supply end negative pole of 40KHz ultrasonic wave emitter and the power supply end negative pole of 25KHz ultrasonic wave emitter electricity respectively, and the output of current amplification circuit is connected with the input of single -chip microcomputer electricity.

[0008] Further, the single-chip microcomputer is an STM32F103 type single-chip microcomputer.

[0009] Further, the MOS pipe drive circuit includes an IR2102 drive chip, a Hin pin of the IR2102 drive chip is electrically connected with a PA0 pin of the single-chip microcomputer, a Lin pin is electrically connected with a PA1 pin of the single-chip microcomputer, a Ho pin is electrically connected with a grid of the first MOS pipe, a Vs pin is electrically connected with a source of the first MOS pipe, and a Lo pin is electrically connected with a grid of the second MOS pipe.

[0010] The utility model has the advantages of:

[0011] The utility model provides a kind of anti-recording shielding instrument power amplifier launch device, two different frequency ultrasonic wave control signals (40KHz and 25KHz) are sent by single-chip microcontroller, and interference effect is enhanced using double-frequency interference waveform;The control signal of output is controlled after MOS tube drive circuit the on-off of corresponding MOS tube, and ultrasonic wave interference source is emitted by 40KHz ultrasonic wave emitter and 25KHz ultrasonic wave emitter, since the internal resistance of MOS tube is small, can be amplified to output power, realize the high-power emission of ultrasonic wave, enhance emission distance;Finally, the working current of two ultrasonic wave emitters is collected by sampling resistance and current amplification circuit, and acquisition signal is sent to single-chip microcontroller, and single-chip microcontroller adjusts the PWM value of ultrasonic wave emission control signal according to sampling signal, realizes constant-power emission. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 It is the principle block diagram of the utility model embodiment.

[0013] Figure 2 It is the circuit diagram of the single-chip microcontroller of the utility model embodiment.

[0014] Figure 3 It is the circuit diagram of MOS tube drive circuit, MOS tube switch circuit and sampling resistance of the utility model embodiment.

[0015] Figure 4 It is the circuit diagram of current amplification circuit of the utility model embodiment.

[0016] Figure 5 It is the adjustment schematic diagram of 40KHz output waveform duty cycle according to current size of single-chip microcomputer of the utility model embodiment. DETAILED DESCRIPTION

[0017] The utility model is described below in conjunction with the drawings, the specific embodiment described here is only used to explain and interpret the utility model, and is not used to limit the utility model, on the premise that not departing from the design spirit of the utility model, the various deformation and improvement of the technical scheme of the utility model of ordinary skill to the utility model, all should fall into the protection scope of the utility model.

[0018] As Figures 1 to 5 Shown, the anti-recording shielding instrument power amplifier launch device of the utility model embodiment, including single-chip microcontroller, MOS tube drive circuit, MOS tube switch circuit, sampling resistance, current amplification circuit and power module.

[0019] The MOSFET driver circuit has two input terminals electrically connected to the two output terminals of the microcontroller, which output ultrasonic control signals at frequencies of 40kHz and 25kHz, respectively. The MOSFET switching circuit includes a first MOSFET switching circuit and a second MOSFET switching circuit. The first MOSFET switching circuit includes a first MOSFET and a 40kHz ultrasonic transmitter. The gate of the first MOSFET is electrically connected to the output terminal of the MOSFET driver circuit, the drain of the first MOSFET is electrically connected to the power supply module, and the source of the first MOSFET is electrically connected to the positive terminal of the 40kHz ultrasonic transmitter's power supply. The second MOSFET switching circuit includes a second MOSFET and a 25kHz ultrasonic transmitter. The gate of the second MOSFET is electrically connected to the output terminal of the MOSFET driver circuit, the drain of the second MOSFET is electrically connected to the negative terminal of the 25kHz ultrasonic transmitter's power supply, and the positive terminal of the 25kHz ultrasonic transmitter's power supply is electrically connected to the power supply module. The sampling resistors include a first sampling resistor and a second sampling resistor. One end of the first sampling resistor is electrically connected to the negative terminal of the power supply of the 40kHz ultrasonic transmitter, and the other end is electrically connected to the GND terminal. One end of the second sampling resistor is electrically connected to the source of the second MOSFET, and the other end is electrically connected to the GND terminal. The input terminals of the current amplifier circuit are electrically connected to the negative terminals of the power supply of both the 40kHz and 25kHz ultrasonic transmitters, respectively. The output terminal of the current amplifier circuit is electrically connected to the input terminal of the microcontroller.

[0020] like Figure 2 As shown, this embodiment uses an STM32F103 microcontroller to generate ultrasonic control signals with frequencies of 40kHz and 25kHz, representing two different frequency ultrasonic interference waveforms. The 40kHz ultrasonic control signal is output from pin PA0, and the 25kHz ultrasonic control signal is output from pin PA1. Due to the mutual diffraction of the two different waveforms, the shielding effect of the shielding device can be effectively improved.

[0021] The power module in this embodiment can provide 5V DC power and 12V DC power to provide operating voltage to each component.

[0022] like Figure 3 As shown, the MOS transistor driving circuit of this embodiment includes an IR2102 driver chip U2. In the circuit, the first MOS transistor is represented by Q1, the second MOS transistor is represented by Q2, the 40KHz ultrasonic transmitter is represented by LS1, the 25KHz ultrasonic transmitter is represented by LS2, the first sampling resistor is represented by resistor R5, and the second sampling resistor is represented by resistor R6.

[0023] The Vcc pin of the IR2102 drive chip of the embodiment is electrically connected with a 12V DC power supply; the Hin pin is electrically connected with the PA0 pin of the single-chip microcomputer; the Lin pin is electrically connected with the PA1 pin of the single-chip microcomputer; the Com pin is electrically connected with the GND terminal; the Vb pin is electrically connected with a 12V DC voltage, and a diode D1 is arranged on the line; the Ho pin is electrically connected with the gate of the first MOS tube, and a resistor R3 is arranged on the line; the Vs pin is electrically connected with the source of the first MOS tube; and the Lo pin is electrically connected with the gate of the second MOS tube, and a resistor R4 is arranged on the line.

[0024] Since the control signal generated by the single-chip microcomputer has weak driving capability and cannot normally drive the switch of the MOS tube, the IR2102 chip is needed to drive the switch state of the MOS tube. When the Ho pin of the U2 chip outputs a high level, the first MOS tube Q1 is turned on, the 12V power supply supplies power to the 40KHz ultrasonic wave emitter LS1, and the vibration piece inside the 40KHz ultrasonic wave emitter LS1 contracts; when the Ho pin of the U2 chip outputs a low level, the first MOS tube Q1 is cut off, the 12V power supply is disconnected from the 40KHz ultrasonic wave emitter LS1, and the vibration piece inside the 40KHz ultrasonic wave emitter LS1 relaxes; by controlling the level state (40KHz control signal) of the Ho pin of the U2 chip, the LS1 can emit 40KHz ultrasonic wave signals to interfere with the normal work of the sound recorder. At this time, the first sampling resistor R5 collects the working current flowing through the 40KHz ultrasonic wave emitter LS1.

[0025] When the Lo pin of the U2 chip outputs a high level, the second MOS tube Q2 is turned on, the 12V power supply supplies power to the 25KHz ultrasonic wave emitter LS2, and the vibration piece inside the 25KHz ultrasonic wave emitter LS2 contracts; when the Lo pin of the U2 chip outputs a low level, the second MOS tube Q2 is cut off, the 12V power supply is disconnected from the 25KHz ultrasonic wave emitter LS2, and the vibration piece inside the 25KHz ultrasonic wave emitter LS2 relaxes; by controlling the level state (25KHz control signal) of the Lo pin of the U2 chip, the 25KHz ultrasonic wave emitter LS2 can emit 25KHz ultrasonic wave signals to interfere with the normal work of the sound recorder. At this time, the second sampling resistor R6 collects the working current flowing through the emission head of the 25KHz ultrasonic wave emitter LS2.

[0026] The on-off of the corresponding MOS tube is controlled by the MOS tube switch circuit to drive the emission of the ultrasonic wave control signal. Since the internal resistance of the MOS tube is small, the large-power emission of the ultrasonic wave can be realized, and the emission distance is enhanced.

[0027] As Figure 4As shown, the current amplification circuit of the embodiment includes an LM358 chip, a resistor R1, a resistor R2, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a capacitor C1 and a capacitor C2, wherein the IN1+ pin of the LM358 chip is electrically connected with the negative pole of the power supply end of the 40KHz ultrasonic wave transmitter and the GND end respectively; the IN1- pin of the LM358 chip is electrically connected with the OUT1 pin and the GND end thereof respectively; the IN2+ pin of the LM358 chip is electrically connected with the source electrode of the second MOS tube; the IN2- pin of the LM358 chip is electrically connected with the OUT2 pin and the IN2+ pin thereof respectively; the OUT1 pin of the LM358 chip is electrically connected with the PA2 pin of the single-chip microcomputer; the OUT2 pin of the LM358 chip is electrically connected with the PA3 pin of the single-chip microcomputer; the resistor R1 is arranged on the line between the IN1- pin and the GND end of the LM358 chip; the resistor R2 is arranged on the line between the IN1- pin of the LM358 chip and the OUT1 pin of the LM358 chip; the resistor R7 and the capacitor C2 are arranged on the line between the IN2- pin and the IN2+ pin of the LM358 chip; the resistor R8 is arranged on the line between the IN2- pin and the OUT2 pin of the LM358 chip; the resistor R9 is arranged on the line between the IN1+ pin of the LM358 chip and the negative pole of the power supply end of the 40KHz ultrasonic wave transmitter; the resistor R10 is arranged on the line between the IN2+ pin of the LM358 chip and the source electrode of the second MOS tube; and the capacitor C1 is arranged on the line between the IN1+ pin and the GND end of the LM358 chip.

[0028] In the current amplification circuit, the resistors R9, R1 and R2 are the current amplification proportional resistors of the 40KHz ultrasonic wave transmitter, and the amplification multiple thereof is:

[0029]

[0030] The resistors R10, R7 and R8 are the current amplification proportional resistors of the 25KHz ultrasonic wave transmitter, and the amplification multiple thereof is:

[0031]

[0032] The current amplification circuit amplifies the sampling signal on the sampling resistor, and improves the sampling precision.

[0033] With the change of temperature, the conduction resistance of the MOS tubes Q1 and Q2 will change, which affects the size of the output power. The single-chip microcomputer is used to perform AD conversion on the output current of the operational amplifier, the duty cycle of the output waveform is adjusted according to the size of the sampled current, and constant power output is realized. Taking the 40KHz output waveform as an example, the adjustment mode is as shown in Figure 5

[0034] ​The utility model discloses a use principle is: through the singlechip emission two different frequency ultrasonic wave emission control signal (40KHz with 25KHz), utilize double -frequency interference waveform can enhance the interference effect, and the control signal of output is controlled the on -off of corresponding MOS pipe after MOS pipe drive circuit, and through 40KHz ultrasonic wave emitter and 25KHz ultrasonic wave emitter emit ultrasonic wave interference source, because the internal resistance of MOS pipe is small, can amplify the output power, realize ultrasonic wave's high -power emission, enhance the emission distance, finally through sampling resistance and current amplification circuit gather two ultrasonic wave emitter's working current, and will gather signal send to singlechip, and singlechip adjusts the PWM value of ultrasonic wave emission control signal according to sampling signal, realizes constant -power emission.

Claims

1. A kind of anti-recording shield instrument power amplifier emission device, it is characterized by: The ultrasonic wave generator comprises a single-chip microcomputer, a MOS tube driving circuit, a MOS tube switching circuit, a sampling resistor, a current amplification circuit and a power module, wherein, Two input ends of the MOS tube driving circuit are electrically connected with two output ends of the single-chip microcomputer respectively, and the two output ends of the single-chip microcomputer respectively output an ultrasonic wave control signal with a frequency of 40KHz and an ultrasonic wave control signal with a frequency of 25KHz; The MOS tube switching circuit comprises a first MOS tube switching circuit and a second MOS tube switching circuit; the first MOS tube switching circuit comprises a first MOS tube and a 40KHz ultrasonic wave transmitter, a gate of the first MOS tube is electrically connected with an output end of the MOS tube driving circuit, a drain of the first MOS tube is electrically connected with the power module, and a source of the first MOS tube is electrically connected with a positive power supply end of the 40KHz ultrasonic wave transmitter; the second MOS tube switching circuit comprises a second MOS tube and a 25KHz ultrasonic wave transmitter, a gate of the second MOS tube is electrically connected with an output end of the MOS tube driving circuit, a drain of the second MOS tube is electrically connected with a negative power supply end of the 25KHz ultrasonic wave transmitter, and a positive power supply end of the 25KHz ultrasonic wave transmitter is electrically connected with the power module; The sampling resistor comprises a first sampling resistor and a second sampling resistor, one end of the first sampling resistor is electrically connected with the negative power supply end of the 40KHz ultrasonic wave transmitter, and the other end is electrically connected with a GND end; one end of the second sampling resistor is electrically connected with the source of the second MOS tube, and the other end is electrically connected with the GND end; Input ends of the current amplification circuit are electrically connected with the negative power supply end of the 40KHz ultrasonic wave transmitter and the negative power supply end of the 25KHz ultrasonic wave transmitter respectively, and an output end of the current amplification circuit is electrically connected with an input end of the single-chip microcomputer.

2. The anti-recording shield instrument power amplifier transmitting device according to claim 1, characterized in that: The single-chip microcomputer adopts an STM32F103 type single-chip microcomputer.

3. The anti-recording shield instrument power amplifier transmitting device according to claim 2, characterized in that: The MOS tube driving circuit comprises an IR2102 driving chip, a Hin pin of the IR2102 driving chip is electrically connected with a PA0 pin of the single-chip microcomputer, a Lin pin is electrically connected with a PA1 pin of the single-chip microcomputer, a Ho pin is electrically connected with the gate of the first MOS tube, a Vs pin is electrically connected with the source of the first MOS tube, and a Lo pin is electrically connected with the gate of the second MOS tube.

4. The anti-recording shield instrument power amplifier transmitting device according to claim 2, characterized in that: The current amplification circuit comprises an LM358 chip, a resistor R1, a resistor R2, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a capacitor C1 and a capacitor C2, wherein, an IN1+ pin of the LM358 chip is electrically connected with the negative power supply end of the 40KHz ultrasonic wave transmitter and the GND end respectively; an IN1- pin of the LM358 chip is electrically connected with an OUT1 pin and the GND end respectively; an IN2+ pin of the LM358 chip is electrically connected with the source of the second MOS tube; an IN2- pin of the LM358 chip is electrically connected with an OUT2 pin and the IN2+ pin respectively; the OUT1 pin of the LM358 chip is electrically connected with a PA2 pin of the single-chip microcomputer; the OUT2 pin of the LM358 chip is electrically connected with a PA3 pin of the single-chip microcomputer; the resistor R1 is arranged on a line between the IN1- pin of the LM358 chip and the GND end. The resistor R2 is arranged on the line between the IN1-pin of the LM358 chip and the OUT1-pin of the LM358 chip; The resistor R7 and the capacitor C2 are arranged on the line between the IN2-pin and the IN2+ pin of the LM358 chip; The resistor R8 is arranged on the line between the IN2-pin and the OUT2 pin of the LM358 chip; The resistor R9 is arranged on the line between the IN1+ pin of the LM358 chip and the negative pole of the power supply of the 40KHz ultrasonic wave transmitter; The resistor R10 is arranged on the line between the IN2+ pin of the LM358 chip and the source of the second MOS tube; The capacitor C1 is arranged on the line between the IN1+ pin of the LM358 chip and the GND terminal.

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