Novel anti-recording device

Abstract

The invention relates to the technical field of information security maintenance, in particular to novel anti-recording equipment which comprises a microphone pickup module, an audio amplification module, a controller module, a clock module, a conversion circuit module, an oscillating circuit module, an AM modulation module, an analog switch module and an ultrasonic transmitting module. According to the invention, the random signal sequence is generated through the conversion circuit module, and the random signal sequence is loaded to a 40KHz carrier wave through the AM modulation module, so that the sound playing and recording effect can be effectively improved. And the transmitting power of the ultrasonic transmitting module can be adaptively controlled, specifically, the controller module judges the distance between a speaker and the recording equipment according to the amplified sound signal, so that the state of the analog switch module is controlled, the ultrasonic power adaptive to the distance is obtained, and the radiation to a human body is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of information security maintenance, and in particular to a novel anti-recording device. Background Art

[0002] At present, with the rapid development of science and technology, more and more digital devices, such as smart phones and digital voice recorders, have recording functions. In order to keep state secrets and protect personal privacy, in some confidential meeting rooms or private places, it is necessary to strictly prevent irrelevant personnel from eavesdropping and leaking secrets, and it is strictly forbidden for participants to use digital devices for recording and videotaping. However, as digital devices are getting smaller and smaller, and eavesdropping and recording equipment are becoming more and more concealed, it is very difficult to completely eliminate the phenomenon of eavesdropping and recording. Therefore, how to effectively keep state secrets and protect personal privacy has become the most important issue in the industry. Innovative methods, devices and systems for preventing recording and eavesdropping are imperative. In business meetings and important occasions, it is also necessary to use anti-recording interference shielding devices to interfere with the recording function of recording equipment (such as mobile phones and voice recorders) to prevent the leakage of important information. However, the current anti-recording equipment has the following shortcomings:

[0003] 1. The interference waveform uses 40KHz ultrasonic wave, which has a single waveform and poor anti-recording effect.

[0004] 2. Prevent recording of all waveforms by using a fixed transmission power or manually adjusting the transmission power to cause radiation to the human body.

[0005] In view of this, a new type of anti-recording device is needed. Summary of the invention

[0006] In view of the problems in the prior art, the present invention provides a new type of anti-recording device. The specific technical scheme is as follows: a new type of anti-recording device, including a microphone pickup module, an audio amplifier module, a controller module, a clock module, a conversion circuit module, an oscillation circuit module, an AM modulation module, an analog switch module, and an ultrasonic emission module;

[0007] The microphone pickup module, audio amplifier module, and controller module are connected in sequence; the clock module, conversion circuit module, and analog switch module are connected to the controller module respectively; the analog switch module is connected to the ultrasonic emission module;

[0008] The conversion circuit module, the oscillation circuit module, and the ultrasonic emission module are respectively connected to the AM modulation module;

[0009] The microphone pickup module is used to collect external sound signals;

[0010] The audio amplification module is used to amplify the collected sound signal to obtain an amplified sound signal;

[0011] The clock module is used to provide a clock source for the control module;

[0012] The controller module is used to detect the size of the amplified sound signal, and output an analog switch control signal according to the size of the sound signal, as well as a random number of the time of the random acquisition clock source;

[0013] The conversion circuit module is used to output a random signal sequence according to the time random number;

[0014] The oscillation circuit module is used to generate a 40KHz ultrasonic transmission carrier;

[0015] The AM modulation module is used to perform AM modulation on the random signal sequence and the 40KHz ultrasonic transmission carrier to generate a random carrier sequence;

[0016] The analog switch module is used to control the state of the analog switch according to the analog switch control signal output by the controller module;

[0017] The ultrasonic transmitting module is used to generate an ultrasonic random interference signal according to a random carrier sequence and a state of an analog switch.

[0018] Preferably, it also includes a filtering module, which is connected to the microphone pickup module and the audio amplification module respectively.

[0019] Preferably, the clock module includes a PCF8563 clock chip.

[0020] Preferably, the conversion circuit module includes a DAC5574 conversion chip.

[0021] Preferably, the method in which the conversion circuit module outputs a random signal sequence according to the time random number is as follows:

[0022] The clock module accumulates time with a period of 1mS;

[0023] The controller module collects the ones and tens digits of the clock module to obtain a value N ranging from 0 to 99;

[0024] The voltage amplitude of the random signal sequence output by the conversion circuit module is calculated as follows:

[0025]

[0026] Among them, A is the set magnification, U DC A power supply voltage input to the conversion circuit module;

[0027] The pulse width T of the random signal sequence output by the conversion circuit module is obtained by the linear congruential formula, which is calculated as follows: T n+1 =(T n×7+8)mod9;

[0028] Among them, T n is the pulse width of the nth random signal sequence, T n+1 is the pulse width of the n+1th random signal sequence.

[0029] Preferably, the oscillation circuit module includes a NE555 chip; the 3rd pin of the NE555 chip is an output pin, the 4th pin and the 8th pin are connected to the power supply VCC, the 1st pin is grounded, and the 5th pin is grounded through the capacitor C4; the 7th pin is connected to the movable end of the sliding resistor VR1, the 6th pin and the 2nd pin are respectively connected to one end of the capacitor C3 and one end of the sliding resistor VR1, the other end of the capacitor C3 is grounded, the other end of the sliding resistor VR1 is connected to the resistor R3, and the other end of the resistor R3 is connected to the power supply VCC.

[0030] Preferably, the AM modulation module includes an AD633JN multiplier chip.

[0031] Preferably, the analog switch module includes a CH442 analog switch chip, and the ultrasonic emission module includes an OP07 operational amplifier chip; the first pin of the CH442 analog switch chip is connected to the controller module, the fourth pin and the sixth pin are connected to the output end of the OP07 operational amplifier chip, the tenth pin is connected to the power supply VCC, the fifth pin and the ninth pin are grounded, the second pin is connected to the negative feedback end of the OP07 operational amplifier chip through a resistor R18, and the seventh pin is connected to the negative feedback end of the OP07 operational amplifier chip through a resistor R17;

[0032] The negative feedback end of the OP07 operational amplifier chip is grounded through a resistor R14 and connected to the output end of the OP07 operational amplifier chip through a resistor R16. The positive feedback end of the OP07 operational amplifier chip is connected to the AM modulation module through a resistor R5.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention generates a random signal sequence through a conversion circuit module, and loads the random signal sequence onto a 40KHz carrier through an AM modulation module, which can effectively improve the recording effect. Moreover, the transmission power of the ultrasonic transmission module can be adaptively controlled. Specifically, the controller module determines the distance between the speaker and the recording device according to the amplified sound signal, and then controls the state of the analog switch module to obtain ultrasonic power adaptive to the distance, thereby reducing radiation to the human body. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0036] Figure 1 It is the principle diagram of the device of the present invention;

[0037] Figure 2 It is the circuit schematic diagram of microphone pickup module, filter module, amplifier module and controller;

[0038] Figure 3 It is a circuit schematic diagram of a clock module, a controller module, and a conversion circuit module;

[0039] Figure 4 It is the circuit schematic diagram of the oscillation circuit module;

[0040] Figure 5 This is the circuit schematic diagram of the AM modulation module;

[0041] Figure 6 This is the schematic diagram of AM modulation;

[0042] Figure 7 This is the principle diagram of the generation of ultrasonic random interference waveform;

[0043] Figure 8 Schematic diagram for generating random time values ​​for the clock module;

[0044] Fig. 9 is a schematic diagram of the voltage amplitude of a random signal sequence;

[0045] Fig.10 Schematic diagram of the pulse width of a random signal sequence;

[0046] Fig.11 It is the circuit schematic diagram of the analog switch module and the ultrasonic transmitting module;

[0047] Fig.12 This is the schematic diagram of the ultrasonic transmitter module emitting ultrasonic waves. DETAILED DESCRIPTION

[0048] 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 described embodiments are 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 creative work are within the scope of protection of the present invention.

[0049] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0050] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0051] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0052] like Figure 1 As shown, this embodiment provides a new type of anti-recording device, including a microphone pickup module, a filter module, an audio amplification module, a controller module, a clock module, a conversion circuit module, an oscillation circuit module, an AM modulation module, an analog switch module, and an ultrasonic emission module.

[0053] The microphone pickup module, filter module, audio amplifier module, and controller module are connected in sequence; the clock module, conversion circuit module, and analog switch module are respectively connected to the controller module; the analog switch module is connected to the ultrasonic emission module; the conversion circuit module, oscillation circuit module, and ultrasonic emission module are respectively connected to the AM modulation module.

[0054] The specific working principle is: the microphone pickup module collects external sound signals; the audio amplifier module amplifies the collected sound signals to obtain the amplified sound signals; the clock module provides the clock source for the control module; the controller module detects the size of the amplified sound signal, and outputs the analog switch control signal according to the size of the sound signal, as well as the random time number of the random collection clock source; the conversion circuit module outputs a random signal sequence according to the random time number; the oscillation circuit module generates a 40KHz ultrasonic transmission carrier; the AM modulation module AM ​​modulates the random signal sequence with the 40KHz ultrasonic transmission carrier to generate a random carrier sequence; the analog switch module controls the state of the analog switch according to the analog switch control signal output by the controller module; the ultrasonic transmission module generates an ultrasonic random interference signal according to the random carrier sequence and the state of the analog switch.

[0055] As a preferred embodiment of the present invention, the controller module of the present invention includes a single-chip microcomputer of the STM32 series, and specifically selects a STM32F103ZET6 single-chip microcomputer chip.

[0056] In addition, the controller module can optionally determine whether the collected external sound signal is a voice signal (when a person is speaking) or a music signal, and set the working mode of the anti-recording device of the present invention according to the type of the recognized sound signal. The working modes include the following three types:

[0057] 1. Mixed mode: The anti-recording function is activated when any sound is detected.

[0058] 2. Voice mode: It has anti-recording function for voice signals, but not for music signals.

[0059] 3. Music mode: It has anti-recording function for music signals, but not for voice signals.

[0060] The sound recognition is realized by the single-chip microcomputer STM32, which mainly identifies whether it is a voice signal (human voice) or an audio signal (music sound) according to the frequency of change of the sound signal; and the device of the present invention is provided with indicator lights for voice signals and audio signals and a setting button for the working mode, and the working mode is set by pressing the button, and the device of the present invention can be switched between the mixed mode, voice mode, and music mode by pressing the button, and the user can select the working mode required by himself. When the control module recognizes the category of the input signal, the corresponding function is started according to the working mode of the shielding instrument:

[0061]

[0062] See also Figure 2 In the figure, MIC is a microphone, the filtering module includes capacitor C12, resistor R11, polarity capacitor C15, and the audio amplification module includes NE5532 amplifier chip.

[0063] One end of the microphone MIC is grounded, and the other end is connected to one end of the capacitor C12, and the other end of the capacitor C12 is connected to the 5th pin of the NE5532 amplifier chip. One end of the polarity capacitor C15 is grounded, and the other end is respectively connected to one end of the resistor R11 and one end of the resistor R12, and the other end of the resistor R11 is connected to the 5th pin of the NE5532 amplifier chip, and the other end of the resistor R12 is connected to the 6th pin of the NE5532 amplifier chip. The 6th pin of the NE5532 amplifier chip is also connected to one end of the resistor R13, and the 7th pin of the NE5532 amplifier chip is respectively connected to the other end of the resistor R13 and the controller module.

[0064] The microphone MIC collects external sound signals, and after filtering the high-frequency noise in the sound signals through the filter module, it is input into the audio amplifier module for amplification. The amplified sound signals are input into the control module STM32 for processing. STM32 uses the internal ADC to convert analog signals into digital signals, detects and determines the size of the sound signals, and outputs the analog switch control signal CH442_IN according to the size of the sound signals. Specifically, when the size of the sound signal is less than the set threshold, it means that the device is far away from the sound source, and the output analog switch control signal CH442_IN is high level. When the size of the sound signal is greater than or equal to the set threshold, it means that the device is close to the sound source, and the output analog switch control signal CH442_IN is low level.

[0065] See also Figure 3 As a preferred embodiment of the present invention, the clock module includes a PCF8563 clock chip. The conversion circuit module includes a DAC5574 conversion chip. Among them, the first pin of the PCF8563 clock is respectively connected to one end of the crystal oscillator Y1 and one end of the capacitor C1, and the other end of the capacitor C1 is grounded. The second pin of the PCF8563 clock is respectively connected to the other end of the crystal oscillator Y1 and one end of the capacitor C2, and the other end of the capacitor C2 is grounded.

[0066] See also Figure 4 As a preferred embodiment of the present invention, the 40KHz ultrasonic transmission carrier wave is realized by an oscillation circuit module, and the oscillation circuit module includes a NE555 chip; the third pin of the NE555 chip is an output pin, the fourth pin and the eighth pin are connected to the power supply VCC, the first pin is grounded, and the fifth pin is grounded through a capacitor C4; the seventh pin is connected to the movable end of the sliding resistor VR1, the sixth pin and the second pin are respectively connected to one end of the capacitor C3 and one end of the sliding resistor VR1, the other end of the capacitor C3 is grounded, the other end of the sliding resistor VR1 is connected to the resistor R3, and the other end of the resistor R3 is connected to the power supply VCC. The output center frequency of the carrier wave is adjusted by the charge and discharge circuit composed of R3, VR1, and C3.

[0067] See also Figure 5 As a preferred embodiment of the present invention, the AM modulation module includes an AD633JN multiplier chip. The random signal sequence and the 40KHz ultrasonic transmission carrier sequence are respectively input into the AD633JN multiplier chip for AM modulation to generate a random carrier sequence. The specific principle diagram is as follows Figure 6 shown.

[0068] See also Figure 7 , the principle of ultrasonic random interference waveform is:

[0069] The STM32 controller of the present invention reads the PCF8536 clock chip through the IIC bus to obtain a random time value, and controls the DAC5575 conversion chip to generate a random signal sequence according to the obtained random time value, so as to obtain a random sequence that changes randomly in both value and time; at the same time, the NE555 chip generates a 40KHz ultrasonic transmission carrier; AM modulation is performed on the random signal sequence and the 40KHz ultrasonic transmission carrier sequence to generate a random carrier sequence, so as to control the ultrasonic wave shape emitted by the ultrasonic transmission module.

[0070] Specifically, the method for the conversion circuit module to output a random signal sequence according to the time random number is as follows:

[0071] like Figure 8 As shown, the clock module uses the PCF8536 clock chip to accumulate time with a period of 1mS;

[0072] The controller module collects the units and tens digits of the clock module to obtain a value N of 0 to 99 mS;

[0073] like Fig. 9 As shown, the voltage amplitude of the random signal sequence output by the conversion circuit module is calculated as follows:

[0074]

[0075] Wherein, A is the reference voltage, which is set to 2.5 in this embodiment, and U DC The power supply voltage input to the conversion circuit module is set to 3.3V in this embodiment.

[0076] When N=0, the output voltage is the minimum, Uo=0V; when N=99, the output voltage is the maximum, Uo=3.2V.

[0077] Since there is a certain randomness in time when the controller reads the time value of the PCF8536 time chip, the voltage amplitude of the output random signal sequence is also random in value.

[0078] The pulse width T of the random signal sequence is also a random width, such as Fig.10 As shown, the pulse width T of the random signal sequence output by the conversion circuit module is obtained by the linear congruential formula, and the specific calculation is as follows:

[0079] T n+1 =(T n ×7+8)mod9;

[0080] Among them, T n is the pulse width of the nth random signal sequence, T n+1 is the pulse width of the n+1th random signal sequence. T is between [0 and 9].

[0081] T0=8, the current pulse width T is 8mS;

[0082] T1=(8*7+8)mod9=1, the current pulse width T is 1mS;

[0083] T2=(1*7+8)mod9=6, the current pulse width T is 6mS;

[0084] And so on.

[0085] T9=(4*7+8)mod9=0, the current pulse width T is 0mS.

[0086] See also Fig.11 , the analog switch module includes a CH442 analog switch chip, and the ultrasonic emission module includes an OP07 operational amplifier chip; the first pin of the CH442 analog switch chip is connected to the controller module to receive the CH442_IN control signal, the fourth pin and the sixth pin are connected to the output end of the OP07 operational amplifier chip, the tenth pin is connected to the power supply VCC, the fifth pin and the ninth pin are grounded, the second pin is connected to the negative feedback end of the OP07 operational amplifier chip through a resistor R18, and the seventh pin is connected to the negative feedback end of the OP07 operational amplifier chip through a resistor R17;

[0087] The negative feedback end of the OP07 operational amplifier chip is grounded through a resistor R14 and connected to the output end of the OP07 operational amplifier chip through a resistor R16. The positive feedback end of the OP07 operational amplifier chip is connected to the AM modulation module through a resistor R5.

[0088] See also Fig.12 ,The device judges the distance of the speaker by collecting the size of the surrounding voice ,signals. The STM32 controller obtains the amplitude of the voice ,signal through the internal DAC and controls the switch state of the CH442 analog ,switch chip in the analog switch module, thereby realizing different feedback resistances of the ,op amplifier OP07 and achieving different powers of ultrasonic ,transmission.

[0089] Specifically, the OP07 operational amplifier chip forms a common-mode proportional amplifier circuit, and the output voltage satisfies the following formula:

[0090]

[0091] Among them, U o ' is the output voltage of the OP07 operational amplifier chip, A o is the gain of the OP07 operational amplifier chip, R f is the equivalent feedback resistance of the OP07 operational amplifier chip, U in It is the voltage output by the AM modulation module.

[0092] When the analog switch control signal CH442_IN output by the controller module is at a low level, the resistor R18 in the analog switch module is turned on, the resistor R17 is turned off, and the equivalent feedback resistor R f It is equal to the parallel value of resistor R18 and resistor R16, calculated as follows:

[0093]

[0094] When the analog switch control signal CH442_IN output by the controller module is at a high level, the resistor R18 in the analog switch module is disconnected, the resistor R17 is turned on, and the equivalent feedback resistor R f It is equal to the parallel value of resistor R17 and resistor R16, calculated as follows:

[0095]

[0096] In this embodiment, the details are shown in Table 1 below:

[0097] Table 1 Parameters of ultrasonic transmitter module and analog switch module

[0098]

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A new type of anti-recording device, characterized in that: It includes a microphone pickup module, an audio amplifier module, a controller module, a clock module, a conversion circuit module, an oscillation circuit module, an AM modulation module, an analog switch module, and an ultrasonic emission module; The microphone pickup module, audio amplifier module, and controller module are connected in sequence; the clock module, conversion circuit module, and analog switch module are connected to the controller module respectively; the analog switch module is connected to the ultrasonic emission module; The conversion circuit module, the oscillation circuit module, and the ultrasonic emission module are respectively connected to the AM modulation module; The microphone pickup module is used to collect external sound signals; The audio amplification module is used to amplify the collected sound signal to obtain an amplified sound signal; The clock module is used to provide a clock source for the control module; The controller module is used to detect the size of the amplified sound signal, and output an analog switch control signal according to the size of the sound signal, as well as a random number of the time of the random acquisition clock source; The conversion circuit module is used to output a random signal sequence according to the time random number; The oscillation circuit module is used to generate a 40KHz ultrasonic transmission carrier; The AM modulation module is used to perform AM modulation on the random signal sequence and the 40KHz ultrasonic transmission carrier to generate a random carrier sequence; The analog switch module is used to control the state of the analog switch according to the analog switch control signal output by the controller module; The ultrasonic transmitting module is used to generate an ultrasonic random interference signal according to a random carrier sequence and a state of an analog switch.

2. A novel anti-recording device 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. A novel anti-recording device according to claim 1, characterized in that: The clock module includes a PCF8563 clock chip.

4. A novel anti-recording device according to claim 1, characterized in that: The conversion circuit module includes a DAC5574 conversion chip.

5. A novel anti-recording device according to claim 1, characterized in that: The method in which the conversion circuit module outputs a random signal sequence according to a time random number is as follows: The clock module accumulates time with a period of 1mS; The controller module collects the ones and tens digits of the clock module to obtain a value N ranging from 0 to 99; The voltage amplitude of the random signal sequence output by the conversion circuit module is calculated as follows: Among them, A is the set magnification, U DC A power supply voltage input to the conversion circuit module; The pulse width T of the random signal sequence output by the conversion circuit module is obtained by the linear congruential formula, and the specific calculation is as follows: T n+1 =(T n ×7+8)mod9; Among them, T n is the pulse width of the nth random signal sequence, T n+1 is the pulse width of the n+1th random signal sequence.

6. A novel anti-recording device according to claim 1, characterized in that: The oscillation circuit module includes a NE555 chip; the 3rd pin of the NE555 chip is an output pin, the 4th pin and the 8th pin are connected to the power supply VCC, the 1st pin is grounded, and the 5th pin is grounded through a capacitor C4; the 7th pin is connected to the movable end of the sliding resistor VR1, the 6th pin and the 2nd pin are respectively connected to one end of the capacitor C3 and one end of the sliding resistor VR1, the other end of the capacitor C3 is grounded, the other end of the sliding resistor VR1 is connected to the resistor R3, and the other end of the resistor R3 is connected to the power supply VCC.

7. A novel anti-recording device according to claim 1, characterized in that: The AM modulation module includes an AD633JN multiplier chip.

8. A novel anti-recording device according to claim 1, characterized in that: The analog switch module includes a CH442 analog switch chip, and the ultrasonic emission module includes an OP07 operational amplifier chip; the first pin of the CH442 analog switch chip is connected to the controller module, the fourth pin and the sixth pin are connected to the output end of the OP07 operational amplifier chip, the tenth pin is connected to the power supply VCC, the fifth pin and the ninth pin are grounded, the second pin is connected to the negative feedback end of the OP07 operational amplifier chip through a resistor R18, and the seventh pin is connected to the negative feedback end of the OP07 operational amplifier chip through a resistor R17; the negative feedback end of the OP07 operational amplifier chip is grounded through a resistor R14, and is connected to the output end of the OP07 operational amplifier chip through a resistor R16, and the positive feedback end of the OP07 operational amplifier chip is connected to the AM modulation module through a resistor R5.

Images