An infrared optical communication circuit

Abstract

The present invention provides an infrared light communication circuit, comprising a filter amplifier unit, a signal encoding unit, an infrared light generating unit, an infrared light receiving unit, a signal decoding unit, a power amplifier unit and a plurality of relay units; the filter amplifier unit picks up an audio analog signal, amplifies the audio signal within a specific frequency band and then outputs it; the signal encoding unit encodes the input audio analog signal and then inputs it into the infrared light generating unit; the infrared light generating unit converts the encoded audio signal into a pulse signal and then emits an infrared light signal; the infrared light receiving unit converts the received infrared light into a voltage signal and inputs it into a signal decoding unit, and then outputs an analog signal to the power amplifier unit after decoding; the power amplifier unit amplifies the power of the analog signal and then drives a loudspeaker to emit a voice signal.

Description

Technical Field

[0001] The present invention relates to the field of infrared light communication technology, and in particular to an infrared light communication circuit. Background Art

[0002] Since the early 20th century, wireless communication technology has become the most commonly used means of communication for humans. Compared with traditional optical fiber communication technology, wireless communication technology can transmit large amounts of data, such as voice, data and images, and has the advantages of high flexibility, low maintenance cost and no restrictions on line layout space. Typical wireless communication technologies include Bluetooth technology, NFC, and infrared light communication technology. Bluetooth technology and NFC are both short-range wireless transmission technologies. Although they can achieve wireless data transmission, they are difficult to apply to long-distance wireless communication transmission due to their high cost, short transmission distance, weak anti-interference ability and insufficient information encryption, which limits their large-scale research and development and promotion.

[0003] Infrared optical communication technology transmits audio signals through infrared light as the signal for transmitting information. There is no need to re-establish the frequency band, so infrared optical communication can transmit information within a certain space. Due to the advantages of infrared optical communication technology such as low cost, strong function, high transmission rate, large transmission capacity and high encryption, infrared optical communication is currently widely used in short-distance data and information transmission, or file exchange between single devices. The distance of infrared light transmission of audio signals is relatively limited, which limits its specific application scope. Summary of the invention

[0004] In view of this, the present invention proposes an infrared optical communication circuit with strong anti-interference ability, low power consumption and expandable long-distance audio signal transmission capability.

[0005] The present invention provides an infrared light communication circuit, comprising a filter amplifier unit (1), a signal encoding unit (2), an infrared light generating unit (3), an infrared light receiving unit (4), a signal decoding unit (5), a power amplifier unit (6) and a plurality of relay units (7); the output end of the filter amplifier unit (1) is electrically connected to the input end of the signal encoding unit (2), the output end of the signal encoding unit (2) is electrically connected to the input end of the infrared light generating unit (3), the infrared light receiving unit (4) receives infrared light signals, the output end of the infrared light receiving unit (4) is electrically connected to the input end of the signal decoding unit (5), the output end of the signal decoding unit (5) is electrically connected to the input end of the power amplifier unit (6); the output end of the power amplifier unit (6) is electrically connected to a speaker;

[0006] The filtering and amplifying unit (1) picks up the audio analog signal, amplifies the audio signal within a specific frequency band, and then outputs it;

[0007] The signal encoding unit (2) encodes the input audio analog signal and then inputs the encoded signal into the infrared light generating unit (3);

[0008] The infrared light generating unit (3) converts the encoded audio signal into a pulse signal and then emits an infrared light signal;

[0009] The infrared light receiving unit (4) converts the received infrared light into a voltage signal and inputs the voltage signal into the signal decoding unit (5) for decoding, and then outputs an analog signal to the power amplifying unit (6);

[0010] The power amplifier unit (6) amplifies the power of the analog signal and then drives the loudspeaker to emit a voice signal.

[0011] On the basis of the above technical solution, preferably, the signal encoding unit (2) includes an encoding chip U1, a capacitor C3 and a transistor Q1. The audio analog signal is converted into a voltage signal through a microphone and flows through the capacitor C3. The capacitor C3 filters the voltage signal and inputs it into the analog signal input end of the encoding chip U1. The digital signal output end of the encoding chip U1 outputs a pulse signal, which is amplified by the transistor Q1 and output to the input end of the infrared light generating unit (3). The filtering and amplifying unit (1) filters the input analog signal and converts it into a signal source baseband signal. The signal source baseband signal is converted into a pulse signal through analog-to-digital conversion by the encoding chip U1.

[0012] Further preferably, the infrared light generating unit (3) comprises a first PMW generator, a first NAND gate, a second NAND gate, a third NAND gate, a transistor Q2, a transistor Q3 and a light emitting diode D4, the first input end of the first NAND gate is electrically connected to the output end of the transistor Q1, the second input end of the first NAND gate is electrically connected to the output end of the third NAND gate, and both input ends of the third NAND gate are electrically connected to the output end of the first PMW generator; the output end of the first NAND gate is connected in parallel to the two input ends of the second NAND gate, and the input end of the second NAND gate is electrically connected to the output end of the first PMW generator. The output end is electrically connected to the base of the transistor Q2, the emitter of the transistor Q2 is electrically connected to the base of the transistor Q3, the emitter of the transistor Q3 is grounded, the collector of the transistor Q3 is respectively connected in parallel with the collector of the transistor Q2 and the cathode of the light-emitting diode D4, the anode of the light-emitting diode D4 and the collector of the transistor Q2 are both electrically connected to the VCC power supply; the PMW signal emitted by the first PMW generator is compounded with the pulse signal output by the encoding chip U1, and is cascaded amplified by the transistors Q2 and Q3 to drive the light-emitting diode D4 to emit infrared light.

[0013] More preferably, the infrared light receiving unit (4) comprises a photosensitive diode D5 and a transistor Q4, the anode of the photosensitive diode is electrically connected to the base of the transistor Q4, the emitter of the transistor Q4 is grounded, and the collector of the transistor Q4 is electrically connected to the input end of the signal decoding unit (5); the anode of the photosensitive diode D5 and the collector of the transistor Q4 are also electrically connected to a +12V power supply.

[0014] More preferably, the signal decoding unit (5) includes a second PMW generator and a decoding chip U4, the PMW emitted by the second PMW generator is input into the clock pin of the decoding chip U4, and the clock frequency of the input decoding chip U4 is the same as the clock frequency of the encoding chip U1; the output end of the infrared light receiving unit (4) is electrically connected to the digital signal input end of the decoding chip U4, and the analog signal output end of the decoding chip U4 is electrically connected to the input end of the power amplifier unit (6) after voltage regulation; the decoding chip U4 performs digital-to-analog conversion on the pulse signal received by the infrared light receiving unit (4), and decodes it to obtain a signal source baseband signal.

[0015] Further preferably, the power amplification unit (6) includes an operational amplifier U6, the analog signal output end of the decoding chip U4 is electrically connected to the in-phase input end of the operational amplifier U6, and the inverting input end of the operational amplifier U6 is grounded via a capacitor C13; the output end of the operational amplifier U6 is connected in parallel with a filter circuit consisting of a capacitor C15 and a resistor R43 connected in series; the output end of the operational amplifier U6 amplifies the power of the source baseband signal and then drives the speaker to emit a voice signal.

[0016] More preferably, the encoding chip U1 and the decoding chip U4 are MC34115P or STM32 single chip microcomputers.

[0017] Further preferably, the filtering and amplifying unit (1) comprises an operational amplifier U6 and an operational amplifier U7, wherein the in-phase input terminal of the operational amplifier U6 is respectively connected in parallel with a resistor R50 and one end of a capacitor C19, the other end of the resistor R50 is electrically connected to the input terminal of the audio analog signal, and the other end of the capacitor C19 is grounded; a capacitor C20 is connected in parallel between the in-phase input terminal and the output terminal of the operational amplifier U6; the inverting input terminal of the operational amplifier U6 is respectively connected in parallel with one end of a resistor R52 and one end of a resistor R53, the other end of the resistor R52 is grounded, and the other end of the resistor R53 is connected to the operational amplifier U6. The output end of the operational amplifier U6 is electrically connected to the non-inverting input end of the operational amplifier U7 through the capacitors C21 and C22 connected in series, a resistor R54 is connected in parallel between the series end of the capacitor C21 and the capacitor C22 and the output end of the operational amplifier U7, a resistor R55 is also connected in parallel to the non-inverting input end of the operational amplifier U7, and the output end of the operational amplifier U7 is connected in parallel with two resistors R56 and R57 connected in series in sequence, and the series end of the resistors R56 and R57 is also electrically connected to the reverse input end of the operational amplifier U7; the output end of the operational amplifier U7 is electrically connected to one end of the capacitor C3.

[0018] On the basis of the above technical solution, preferably, it further includes a relay unit (7), the relay unit (7) includes a photosensitive diode D8, a transistor Q5 and light-emitting diodes D9 and D10, the positive electrode of the photosensitive diode D8 is electrically connected to the base of the transistor Q5, the emitter of the transistor Q5 is grounded, and the collector of the transistor Q5 is provided with light-emitting diodes D9 and D10 in series; the relay unit (7) is located between the infrared light generating unit (3) and the infrared light receiving unit (4), and relays the pulse signal emitted by the infrared light generating unit (3) to the input end of the infrared light receiving unit (4).

[0019] The infrared optical communication circuit provided by the present invention has the following beneficial effects compared with the prior art:

[0020] (1) The present invention can realize the conversion of analog signals by configuring a signal encoding unit and a signal decoding unit, thereby eliminating noise interference in relay transmission as much as possible; the infrared light generating unit and the infrared light receiving unit cooperate with a plurality of relay units, so that the pulse signal emitted by the infrared light generating unit can be transmitted over a long distance without loss, thus overcoming the problem that the existing infrared light communication is limited by distance;

[0021] (2) The filter-amplifier unit performs bandpass filtering on the input audio analog signal, filters out its noise part, retains the main frequency band part of its energy and amplifies it;

[0022] (3) The signal encoding unit performs digital-to-analog conversion on the input analog signal and outputs a pulse signal of a specific signal source baseband for further conversion by the infrared light generating unit;

[0023] (4) The infrared light generating unit combines the PMW signal emitted by the first PMW generator with the pulse signal output by the encoding chip U1, and amplifies it by cascade connection of transistors Q2 and Q3 to improve the load carrying capacity and output an infrared light signal with higher energy;

[0024] (5) The signal decoding unit performs digital-to-analog conversion based on the received pulse signal and restores it to the source baseband signal;

[0025] (6) The power amplifier unit amplifies the power of the source baseband signal and drives the speaker to emit a voice signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A system block diagram of an infrared optical communication circuit of the present invention;

[0028] Figure 2 A wiring diagram of a signal encoding unit of an infrared optical communication circuit of the present invention;

[0029] Figure 3 A wiring diagram of an infrared light generating unit of an infrared light communication circuit of the present invention;

[0030] Figure 4 A wiring diagram of an infrared light receiving unit and a signal decoding unit of an infrared light communication circuit of the present invention;

[0031] Figure 5 A wiring diagram of a power amplification unit of an infrared optical communication circuit of the present invention;

[0032] Figure 6 A wiring diagram of a relay unit of an infrared optical communication circuit of the present invention;

[0033] Figure 7 The present invention is a wiring diagram of a filter amplifier unit of an infrared optical communication circuit. DETAILED DESCRIPTION

[0034] The following will be combined with 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 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 creative work are within the scope of protection of the present invention.

[0035] like Figure 1 As shown, the figure shows an infrared light communication circuit, including a filter amplifier unit 1, a signal encoding unit 2, an infrared light generating unit 3, an infrared light receiving unit 4, a signal decoding unit 5, a power amplifier unit 6 and a plurality of relay units 7; the output end of the filter amplifier unit 1 is electrically connected to the input end of the signal encoding unit 2, the output end of the signal encoding unit 2 is electrically connected to the input end of the infrared light generating unit 3, the infrared light receiving unit 4 receives the infrared light signal, the output end of the infrared light receiving unit 4 is electrically connected to the input end of the signal decoding unit 5, the output end of the signal decoding unit 5 is electrically connected to the input end of the power amplifier unit 6; the output end of the power amplifier unit 6 is electrically connected to the speaker; wherein:

[0036] The filtering and amplifying unit 1 picks up the audio analog signal, amplifies the audio signal within a specific frequency band and then outputs it;

[0037] The signal encoding unit 2 encodes the input audio analog signal and then inputs it into the infrared light generating unit 3;

[0038] The infrared light generating unit 3 converts the encoded audio signal into a pulse signal and then emits an infrared light signal;

[0039] The infrared light receiving unit 4 converts the received infrared light into a voltage signal and inputs the voltage signal into the signal decoding unit 5, and then outputs an analog signal to the power amplifying unit 6 after decoding;

[0040] The signal decoding unit 5 converts the received pulse signal into an analog signal;

[0041] The power amplifier unit 6 amplifies the analog signal and drives the speaker to emit a voice signal.

[0042] like Figure 2 As shown, the figure shows a wiring diagram of a signal encoding unit 2. The signal encoding unit 2 includes an encoding chip U1, a capacitor C3 and a transistor Q1. The audio analog signal is changed into a voltage signal through a microphone and flows through the capacitor C3. The capacitor C3 filters the voltage signal and inputs it into the analog signal input end of the encoding chip U1. The digital signal output end of the encoding chip U1 outputs a pulse signal, which is amplified by the transistor Q1 and output to the input end of the infrared light generating unit 3; the filter amplifier unit 1 filters the input analog signal and converts it into a source baseband signal. The source baseband signal is converted into a pulse signal through analog-to-digital conversion by the encoding chip U1. The encoding chip U1 shown in the figure is MC34115P, which is a modem that can realize both modulation and demodulation functions. The analog signal input by capacitor C3 is input into pin 1 of encoding chip U1; pin 2 is the feedback input terminal. When encoding is working, the local analog signal is input from this terminal into the comparator in encoding chip U1. When decoding is working, this pin is left floating or connected to pin 10; pin 9 of encoding chip U1 is the digital output terminal, which is also the encoding output. It is compatible with TTL or CMOS and has a relatively low level. Therefore, transistor Q1 is used for amplification and output, and the output voltage is V1. Pin 10 is the reference voltage output terminal. Pin 14 is the encoding clock input terminal, which determines the working rate of the chip. 8KHz, 16KHz, 32KHz or 64KHz can be selected. Pin 15 is the encoding and decoding selection function. When the level is high, it is the encoding function, and when the level is low, it is the decoding function. Pin 1 shown in the figure is also connected in parallel with the in-phase input terminal of an op amp, and the output terminal of the op amp is used as the input signal of the incremental control input terminal of pin 4.

[0043] like Figure 7As shown, the filtering and amplifying unit 1 includes an operational amplifier U6 and an operational amplifier U7. The in-phase input terminal of the operational amplifier U6 is connected in parallel with one end of the resistor R50 and the capacitor C19, respectively. The other end of the resistor R50 is electrically connected to the input end of the audio analog signal, and the other end of the capacitor C19 is grounded. A capacitor C20 is connected in parallel between the in-phase input terminal and the output terminal of the operational amplifier U6. The inverting input terminal of the operational amplifier U6 is connected in parallel with one end of the resistor R52 and the resistor R53, respectively. The other end of the resistor R52 is grounded, and the other end of the resistor R53 is connected to the output terminal of the operational amplifier U6. The output end of the operational amplifier U6 is electrically connected to the in-phase input end of the operational amplifier U7 through the capacitors C21 and C22 connected in series, a resistor R54 is connected in parallel between the series end of the capacitors C21 and C22 and the output end of the operational amplifier U7, a resistor R55 is also connected in parallel to the in-phase input end of the operational amplifier U7, and the output end of the operational amplifier U7 is connected in parallel to two resistors R56 and R57 connected in series in sequence, and the series end of the resistors R56 and R57 is also electrically connected to the reverse input end of the operational amplifier U7; the output end of the operational amplifier U7 is electrically connected to one end of the capacitor C3. The filtering and amplifying unit 1 realizes bandpass filtering through a two-stage operational amplifier to filter the sound frequency between 340Hz-3KHz.

[0044] like Figure 3 As shown, the infrared light generating unit 3 includes a first PMW generator, a first NAND gate, a second NAND gate, a third NAND gate, a transistor Q2, a transistor Q3 and a light emitting diode D4, the first input end of the first NAND gate is electrically connected to the output end of the transistor Q1, the second input end of the first NAND gate is electrically connected to the output end of the third NAND gate, and both input ends of the third NAND gate are electrically connected to the output end of the first PMW generator; the output end of the first NAND gate is connected in parallel with the two input ends of the second NAND gate, and the output end of the second NAND gate is connected to the output end of the third NAND gate. The base of transistor Q2 is electrically connected, the emitter of transistor Q2 is electrically connected to the base of transistor Q3, the emitter of transistor Q3 is grounded, the collector of transistor Q3 is respectively connected in parallel with the collector of transistor Q2 and the negative electrode of light-emitting diode D4, and the positive electrode of light-emitting diode D4 and the collector of transistor Q2 are both electrically connected to the VCC power supply; the PMW signal emitted by the first PMW generator is compounded with the pulse signal output by the encoding chip U1, and the light-emitting diode D4 is driven to emit infrared light after cascade amplification by transistors Q2 and Q3. The first PMW generator can be generated by a common PMW wave generating chip, or it can be realized by the PMW output end of the STM32 microcontroller. The first NAND gate, the second NAND gate and the third NAND gate can be realized by an integrated chip U3 CD4011B. The conditioned pulse waveform is input into the cascaded transistors Q2 and Q3. The light emitting diode D3 is arranged on the collector of the transistor Q2 and can be used as a working indication signal. The light emitting diode D4 emits infrared light.

[0045] like Figure 4As shown, the infrared light receiving unit 4 includes a photosensitive diode D5 and a transistor Q4, the anode of the photosensitive diode is electrically connected to the base of the transistor Q4, the emitter of the transistor Q4 is grounded, and the collector of the transistor Q4 is electrically connected to the input end of the signal decoding unit 5; the anode of the photosensitive diode D5 and the collector of the transistor Q4 are also electrically connected to the +12V power supply. After receiving the infrared light signal, the photosensitive diode D5 will generate a corresponding signal, which is amplified by the transistor Q4 and input into the input end of the signal decoding unit 5.

[0046] Likewise Figure 4 As shown, the signal decoding unit 5 includes a second PMW generator and a decoding chip U4. The PMW emitted by the second PMW generator is input to the clock pin of the decoding chip U4, and the clock frequency of the input decoding chip U4 is the same as the clock frequency of the encoding chip U1; the output end of the infrared light receiving unit 4 is electrically connected to the digital signal input end of the decoding chip U4, and the analog signal output end of the decoding chip U4 is electrically connected to the input end of the power amplifier unit 6 after voltage regulation; the decoding chip U4 performs digital-to-analog conversion on the pulse signal received by the infrared light receiving unit 4, and decodes to obtain the source baseband signal. The decoding chip U4 can also use MC34115P, which works in the decoding state at this time. The signal is input by pin 13, and the decoded signal is output by pin 7. The second PMW generator generates a PMW waveform correspondingly as the clock signal of the decoding chip U4.

[0047] like Figure 5 As shown, the power amplifier unit 6 includes an operational amplifier U6, the analog signal output end of the decoding chip U4 is electrically connected to the in-phase input end of the operational amplifier U6, and the inverting input end of the operational amplifier U6 is grounded via a capacitor C13; the output end of the operational amplifier U6 is connected in parallel with a filter circuit composed of a capacitor C15 and a resistor R43 in series; the output end of the operational amplifier U6 amplifies the power of the source baseband signal and then drives the speaker to emit a voice signal.

[0048] like Figure 6 As shown, the relay unit 7 includes a photosensitive diode D8, a transistor Q5, and light-emitting diodes D9 and D10, the positive electrode of the photosensitive diode D8 is electrically connected to the base of the transistor Q5, the emitter of the transistor Q5 is grounded, and the collector of the transistor Q5 is provided with light-emitting diodes D9 and D10 in series; the relay unit 7 is located between the infrared light generating unit 3 and the infrared light receiving unit 4, and relays the pulse signal emitted by the infrared light generating unit 3 to the input end of the infrared light receiving unit 4. The relay units 7 are arranged at equal intervals to ensure that the signal does not attenuate due to the extension of the distance.

[0049] Of course, the encoding chip U1 and the decoding chip U4 of the present invention can also adopt an STM32 single-chip microcomputer, which has an ADC function and a PMW output function, has a higher degree of integration, and can simplify the circuit structure.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An infrared optical communication circuit, characterized in that: The invention comprises a filter amplifier unit (1), a signal encoding unit (2), an infrared light generating unit (3), an infrared light receiving unit (4), a signal decoding unit (5), a power amplifier unit (6) and a plurality of relay units (7); the output end of the filter amplifier unit (1) is electrically connected to the input end of the signal encoding unit (2), the output end of the signal encoding unit (2) is electrically connected to the input end of the infrared light generating unit (3), the infrared light receiving unit (4) receives the infrared light signal, the output end of the infrared light receiving unit (4) is electrically connected to the input end of the signal decoding unit (5), the output end of the signal decoding unit (5) is electrically connected to the input end of the power amplifier unit (6); the output end of the power amplifier unit (6) is electrically connected to an external speaker; The filtering and amplifying unit (1) picks up the audio analog signal, amplifies the audio signal within a specific frequency band, and then outputs it; The signal encoding unit (2) encodes the input audio analog signal and then inputs the encoded signal into the infrared light generating unit (3); The infrared light generating unit (3) converts the encoded audio signal into a pulse signal and then emits an infrared light signal; A plurality of relay units (7) are equidistantly distributed between the infrared light generating unit (3) and the infrared light receiving unit (4) to transmit the infrared light emitted by the infrared light generating unit (3) to the input end of the infrared light receiving unit (4); The infrared light receiving unit (4) converts the received infrared light into a voltage signal and inputs the voltage signal into the signal decoding unit (5), and then outputs an analog signal to the power amplifying unit (6) after decoding; The power amplifier unit (6) amplifies the analog signal and drives the loudspeaker to emit a voice signal; The signal encoding unit (2) comprises an encoding chip U1, a capacitor C3 and a transistor Q1. The audio analog signal is converted into a voltage signal by a microphone and flows through the capacitor C3. The capacitor C3 filters the voltage signal and then inputs it into the analog signal input end of the encoding chip U1. The digital signal output end of the encoding chip U1 outputs a pulse signal. The pulse signal is amplified by the transistor Q1 and then output to the input end of the infrared light generating unit (3). The filtering and amplifying unit (1) filters the input analog signal and then converts it into a signal source baseband signal. The signal source baseband signal is converted into a pulse signal by analog-to-digital conversion by the encoding chip U1. The infrared light generating unit (3) comprises a first PMW generator, a first NAND gate, a second NAND gate, a third NAND gate, a transistor Q2, a transistor Q3 and a light emitting diode D4, wherein the first input end of the first NAND gate is electrically connected to the output end of the transistor Q1, the second input end of the first NAND gate is electrically connected to the output end of the third NAND gate, and both input ends of the third NAND gate are electrically connected to the output end of the first PMW generator; the output end of the first NAND gate is connected in parallel to the two input ends of the second NAND gate, and the output end of the second NAND gate is connected to the output end of the third NAND gate. The base of transistor Q2 is electrically connected, the emitter of transistor Q2 is electrically connected to the base of transistor Q3, the emitter of transistor Q3 is grounded, the collector of transistor Q3 is connected in parallel with the collector of transistor Q2 and the cathode of light-emitting diode D4 respectively, the anode of light-emitting diode D4 and the collector of transistor Q2 are both electrically connected to the VCC power supply; the PMW signal emitted by the first PMW generator is compounded with the pulse signal output by the encoding chip U1, and is cascaded amplified by transistors Q2 and Q3 to drive the light-emitting diode D4 to emit infrared light; The infrared light receiving unit (4) comprises a photosensitive diode D5 and a transistor Q4, wherein the anode of the photosensitive diode is electrically connected to the base of the transistor Q4, the emitter of the transistor Q4 is grounded, and the collector of the transistor Q4 is electrically connected to the input end of the signal decoding unit (5); the anode of the photosensitive diode D5 and the collector of the transistor Q4 are also electrically connected to a +12V power supply; The signal decoding unit (5) comprises a second PMW generator and a decoding chip U4, the PMW emitted by the second PMW generator is input into the clock pin of the decoding chip U4, and the clock frequency input into the decoding chip U4 is the same as the clock frequency of the encoding chip U1; the output end of the infrared light receiving unit (4) is electrically connected to the digital signal input end of the decoding chip U4, and the analog signal output end of the decoding chip U4 is electrically connected to the input end of the power amplification unit (6) after voltage regulation; the decoding chip U4 performs digital-to-analog conversion on the pulse signal received by the infrared light receiving unit (4), and decodes to obtain a signal source baseband signal.

2. An infrared optical communication circuit as claimed in claim 1, characterized in that: The power amplification unit (6) comprises an operational amplifier U6, the analog signal output end of the decoding chip U4 is electrically connected to the in-phase input end of the operational amplifier U6, and the inverting input end of the operational amplifier U6 is grounded via a capacitor C13; the output end of the operational amplifier U6 is connected in parallel with a filter circuit consisting of a capacitor C15 and a resistor R43 connected in series; the output end of the operational amplifier U6 amplifies the power of the signal source baseband signal and then drives the speaker to emit a voice signal.

3. An infrared optical communication circuit as claimed in claim 2, characterized in that: The encoding chip U1 and the decoding chip U4 are MC34115P or STM32 single-chip microcomputers.

4. An infrared optical communication circuit as claimed in claim 1, characterized in that: The filtering and amplifying unit (1) comprises an operational amplifier U6 and an operational amplifier U7, wherein the in-phase input terminal of the operational amplifier U6 is respectively connected in parallel with a resistor R50 and one end of a capacitor C19, the other end of the resistor R50 is electrically connected to the input terminal of the audio analog signal, and the other end of the capacitor C19 is grounded; a capacitor C20 is connected in parallel between the in-phase input terminal and the output terminal of the operational amplifier U6; the inverting input terminal of the operational amplifier U6 is respectively connected in parallel with one end of a resistor R52 and one end of a resistor R53, the other end of the resistor R52 is grounded, and the other end of the resistor R53 is connected to the output terminal of the operational amplifier U6. In parallel; the output end of the operational amplifier U6 is electrically connected to the non-inverting input end of the operational amplifier U7 through the series capacitors C21 and C22, a resistor R54 is connected in parallel between the series end of the capacitors C21 and C22 and the output end of the operational amplifier U7, a resistor R55 is also connected in parallel to the non-inverting input end of the operational amplifier U7, and the output end of the operational amplifier U7 is connected in parallel with two resistors R56 and R57 connected in series in sequence, and the series end of the resistors R56 and R57 is also electrically connected to the reverse input end of the operational amplifier U7; the output end of the operational amplifier U7 is electrically connected to one end of the capacitor C3.

5. An infrared optical communication circuit as claimed in claim 1, characterized in that: The relay unit (7) comprises a photosensitive diode D8, a transistor Q5, and light-emitting diodes D9 and D10; the positive electrode of the photosensitive diode D8 is electrically connected to the base of the transistor Q5, the emitter of the transistor Q5 is grounded, and the collector of the transistor Q5 is provided with light-emitting diodes D9 and D10 in series; the relay unit (7) relays the pulse signal emitted by the infrared light generating unit (3) step by step to the input end of the infrared light receiving unit (4).

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