Free space optical communication audio signal propagation demonstration device

Abstract

The utility model provides a free space optical communication audio signal propagation demonstration device. The demonstration device comprises a transmitting end and a receiving end; the transmitting end comprises a same-direction proportional amplifying circuit, a direct-current biasing circuit, a reverse proportional amplifying circuit, a reverse output circuit and a laser; and the receiving end comprises an optical signal receiving circuit, an amplifying module and an audio playing module. The demonstration device can carry out an optical experiment, an amplification circuit experiment and an active filter circuit experiment based on free space optical communication, the knowledge points covered by the experiment content are rich, the understanding of students on the free space optical communication principle, device and application can be deepened through the operation of the experiment, and the teaching efficiency is improved. And students can be helped to consolidate related circuit knowledge. The demonstration device is designed on a desk, is compact in structure, is high in operability, is suitable for experiment teaching of the free space optical communication technology, and fills the blank of the market.

Description

TECHNICAL FIELD

[0001] The utility model relates to communication technical field, especially is free space optical communication audio signal propagation demonstration device. BACKGROUND

[0002] Traditional optical communication technology guides light beam through optical fiber cable to communicate.Compared with traditional optical communication technology, free space optical communication audio signal propagation demonstration device has many advantages, free space optical communication audio signal propagation demonstration device does not need physical medium, with the progress of science and technology, the performance of free space optical communication is gradually improved, and the application in deep space exploration and other fields will be more and more extensive, free space optical communication audio signal propagation demonstration device has higher cost effectiveness, and the maintenance cost is low, and free space optical communication audio signal propagation demonstration device makes the propagation of audio signal in free space not be limited by distance.Similarly, free space optical communication does not need to apply for spectrum resource.However, the existing colleges and universities do not have such a free space optical communication audio signal propagation demonstration device experimental equipment, so there is an urgent need for a free space optical communication audio signal propagation demonstration device that can solve the above problems. SUMMARY

[0003] The utility model provides free space optical communication audio signal propagation demonstration device in view of the deficiency of prior art, the demonstration device is a kind of device that three kinds of signals of light, sound and electricity are converted to each other.The demonstration device fills the market gap in the teaching experiment of this technology in colleges and universities, provides ideal experimental platform for student to be familiar with and master free space optical communication technology, and free space optical communication audio signal propagation demonstration device has low cost and good experience, can increase the interest of student to experiment.

[0004] The utility model is realized through the following technical schemes, the utility model provides free space optical communication audio signal propagation demonstration device, the demonstration device includes transmitting end and receiving end;The transmitting end includes homodirectional proportional amplification circuit, direct current bias circuit, reverse proportional amplification circuit, reverse output circuit and laser instrument;The receiving end includes optical signal receiving circuit, amplification module and audio play module;

[0005] The audio signal is amplified in the audio signal frequency range after the audio signal is converted into an electric signal in the same direction proportional amplification circuit; the amplified electric signal is input into the reverse proportional amplification circuit for reverse amplification, the reverse proportional amplification circuit is also connected with the direct current bias circuit, the direct current bias circuit is used for ensuring that the reverse amplified electric signal can be correctly amplified without distortion in the audio signal range; the reverse amplified electric signal is input into the reverse output circuit, the reverse output circuit reversely amplifies the electric signal again in the audio signal frequency range, at this time, the electric signal is the same as the voltage direction of the input audio signal, then the amplified electric signal is input into the laser, so that the laser carrying the audio signal is emitted, and the laser is emitted into the free space; the optical signal receiving circuit receives the laser in the free space and converts the optical signal into an electric signal, the electric signal is extracted through the active filter circuit, and then the electric signal is amplified through the amplification module, and the amplified electric signal is input into the audio playing module to output the audio signal.

[0006] Further, the input audio signal acts on the non-inverting input end of the NE5532 chip in the same direction proportional amplification circuit through resistance to amplify the electric signal in the audio signal frequency range.

[0007] Further, the direct current bias circuit adopts the NE5532 chip, and the electric signal can be correctly amplified without distortion in the audio signal frequency range, so that the working point is ensured to be in the linear region of amplification.

[0008] Further, the amplified electric signal acts on the inverting input end of the NE5532 chip in the reverse proportional amplification circuit through resistance to reversely amplify the electric signal in the audio signal frequency range.

[0009] Further, the reverse amplified electric signal acts on the inverting input end of the NE5532 chip in the reverse output circuit through resistance to reversely amplify the electric signal again in the audio signal range.

[0010] Further, the optical signal receiving circuit comprises a PN photodiode, the PN photodiode converts the change of received light into the change of current by using the photosensitive characteristic of the PN junction, and the optical signal acts on the non-inverting input end of the NE5532 chip in the optical signal receiving circuit through resistance to realize current-voltage conversion.

[0011] Further, the amplification module adopts the TDA2030A digital power amplifier module to amplify the electric signal.

[0012] Further, the audio playing module adopts a loudspeaker with a power of 0.5 W to output the audio signal.

[0013] The audio signal is amplified in the audio signal frequency range after the audio signal is converted into an electric signal in the same direction proportional amplification circuit; the amplified electric signal is input into the reverse proportional amplification circuit for reverse amplification, the reverse proportional amplification circuit is also connected with the direct current bias circuit, the direct current bias circuit is used for ensuring that the reverse amplified electric signal can be correctly amplified without distortion in the audio signal range; the reverse amplified electric signal is input into the reverse output circuit, the reverse output circuit reversely amplifies the electric signal again in the audio signal frequency range, at this time, the electric signal is the same as the voltage direction of the input audio signal, then the amplified electric signal is input into the laser, so that the laser carrying the audio signal is emitted, and the laser is emitted into the free space; the optical signal receiving circuit receives the laser in the free space and converts the optical signal into an electric signal, the electric signal is extracted through the active filter circuit, and then the electric signal is amplified through the amplification module, and the amplified electric signal is input into the audio playing module to output the audio signal.

[0014] The free space optical communication audio signal propagation demonstration device is a kind of optical signal propagation technology, laser is used as the carrier of sound signal, and is transmitted to the designated position in free space, and is demodulated by the receiving end, so that the stable transmission of sound signal in free space is realized.

[0015] The free space optical communication audio signal propagation demonstration device adopts proportional operation amplification circuit in multiple places, and based on the characteristics of virtual short and virtual break of the operational amplifier and the design of the circuit, the input signal is amplified in proportion, and the free space optical communication audio signal propagation demonstration device can directly amplify the audio signal on the transmission path. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or the prior art description, and obviously, the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of the provided drawings.

[0017] Figure 1 It is the overall structure schematic diagram of the free space optical communication audio signal propagation demonstration device.

[0018] Figure 2 It is the transmitting end structure schematic diagram of the free space optical communication audio signal propagation demonstration device.

[0019] Figure 3 It is the receiving end structure schematic diagram of the free space optical communication audio signal propagation demonstration device. DETAILED DESCRIPTION

[0020] The technical scheme in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application, and obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0021] The utility model provides a free space optical communication audio signal propagation demonstration device, the demonstration device includes emission end and receiving end, the emission end includes homodirectional proportional amplification circuit, direct current bias circuit, reverse proportional amplification circuit, reverse output circuit and laser instrument, the receiving end includes optical signal receiving circuit, amplification module and audio frequency play module,

[0022] The audio signal is converted into an electrical signal in the homodirectional proportional amplification circuit, and the electrical signal is amplified in the audio signal frequency range; the amplified electrical signal is input to the reverse proportional amplification circuit for reverse amplification, and the reverse proportional amplification circuit is also connected with the direct current bias circuit, which is used to ensure that the reverse amplified electrical signal can be correctly amplified without distortion in the audio signal range; the reverse amplified electrical signal is input to the reverse output circuit, which reversely amplifies the electrical signal again in the audio signal frequency range, and at this time, the electrical signal has the same voltage direction as the input audio signal; then the amplified electrical signal is input to the laser instrument, so that the laser instrument emits laser carrying the audio signal, and the laser is emitted into the free space; the optical signal receiving circuit receives the laser in the free space and converts the optical signal into an electrical signal; after the useful electrical signal is extracted by the active filter circuit, the electrical signal is amplified by the amplification module, and the amplified electrical signal is input to the audio frequency play module to output the audio signal.

[0023] The input audio signal is amplified in the audio signal frequency range by acting on the in-phase input end of the NE5532 chip in the homodirectional proportional amplification circuit through resistance.

[0024] The direct current bias circuit is a technology for setting the static working point of the circuit, ensuring that the circuit operates stably and reliably in the normal working range, adding appropriate direct current voltage to shift the working point of the circuit to the appropriate range; the direct current bias circuit adopts the NE5532 chip, which ensures that the electrical signal can be correctly amplified without distortion in the audio signal frequency range, and ensures that the working point is in the linear region of amplification.

[0025] The amplified electrical signal is reverse amplified in the audio signal frequency range by acting on the inverting input end of the NE5532 chip in the reverse proportional amplification circuit through resistance.

[0026] The reverse amplified electrical signal is reverse amplified again in the audio signal range by acting on the inverting input end of the NE5532 chip in the reverse output circuit through resistance.

[0027] The light signal receiving circuit comprises a PN photodiode, which is a far infrared receiving tube and a device for converting optical energy into electrical energy; the photodiode utilizes the photosensitive property of a PN junction to convert the change of the received light into the change of the current, and the light signal is applied to the non-inverting input end of the NE5532 chip in the light signal receiving circuit through resistance, so as to realize the conversion of current and voltage.

[0028] The amplification module adopts a TDA2030A digital power amplifier module to amplify the electrical signal.

[0029] The audio playing module adopts a loudspeaker with a power of 0.5 W to output the audio signal.

[0030] The demonstration device can carry out optical experiments, amplification circuit experiments and active filter circuit experiments based on free space optical communication, the knowledge points covered by the experiment contents are rich, and through the operation of the experiment, the students can deepen the understanding of the principle, device and application of free space optical communication, and can help the students to consolidate the related circuit knowledge.

[0031] Embodiment

[0032] The demonstration device comprises Figure 1 a whole structure as shown in the figure, Figure 2 a transmitting end structure as shown in the figure, Figure 3 a receiving end structure as shown in the figure.

[0033] As Figure 1 shown, the demonstration device comprises a transmitting end and a receiving end, wherein the transmitting end comprises a same-direction proportional amplification circuit, a direct current bias circuit, a reverse proportional amplification circuit, a reverse output circuit and a laser; the receiving end comprises a light signal receiving circuit, an amplification module and an audio playing module.

[0034] As Figure 2As shown, the transmitting end's same direction proportional amplification circuit, reverse proportional amplification circuit, reverse output circuit, laser are sequentially connected, the input audio signal is modulated into an electric signal in the same direction proportional amplification circuit, the electric signal acts on the non-inverting input terminal of the NE5532 chip through resistance, forming a non-inverting proportional amplification circuit, amplifying the electric signal in the frequency range of the audio signal, the direct current bias circuit adopts the NE5532 chip, ensuring that the amplified electric signal can be correctly inversely amplified and not distorted in the frequency range of the audio signal, and at the same time, the working point is in the linear region of amplification, at the same time, the amplified electric signal acts on the inverting input terminal of the NE5532 chip through resistance, forming an inverting proportional amplification circuit, however, the voltage of the electric signal at this time is a reverse voltage, and then the electric signal is inversely amplified in the frequency range of the audio signal by the NE5532 chip through the reverse output circuit, the electric signal at this time is the same as the voltage direction of the input audio signal, and the electric signal is connected to the laser, so that the laser emits a laser carrying the audio signal, and the laser is emitted into the free space.

[0035] As shown in the figure, Figure 3 As shown, the receiving end's optical signal receiving circuit, amplification module, audio playing module are sequentially connected, the photodiode of the receiving circuit receives the optical signal in the free space and converts the optical signal into an electric signal, an active filter circuit is adopted, useful electric signals are extracted, and then the electric signal is amplified through the TDA2030A digital power amplifier module, the TDA2030A digital power amplifier module is a 18W single-channel power amplifier, which is suitable for 2-8Ω power 30W or less loudspeaker, and the power supply power of the TDA2030A digital power amplifier module is equal to the output voltage multiplied by the output current, and the electric signal amplified by the TDA2030A digital power amplifier module is directly connected to the loudspeaker to output the audio signal.

[0036] The utility model provides a kind of free space optical communication audio signal propagation demonstration device, and the demonstration device combines laser and optical element such as photodiode, realizes the mutual conversion between audio signal and optical signal, and then combines same direction proportional amplification circuit, direct current bias circuit, reverse proportional amplification circuit, reverse output circuit, optical signal receiving circuit, amplification module and audio playing module to realize optical communication demonstration based on free space light.The same direction proportional amplification circuit, direct current bias circuit, reverse proportional amplification circuit, reverse output circuit, laser need complete the conversion of audio signal to electric signal and then to optical signal, and the above-mentioned receiving circuit, amplification module and audio playing module sequentially convert optical signal to electric signal, amplify electric signal and play audio.The utility model explores free space optical communication technology to enable user to obtain practical operation and good interactive experience, improve user's interest and learning initiative to communication technology, which is conducive to deepening understanding of optical communication technology and exploring the application potential of optical communication in the field of Internet of Things and wireless transmission.

[0037] The free space optical communication audio signal propagation demonstration device is described in detail above, the principle and implementation mode of the free space optical communication audio signal propagation demonstration device are described by applying specific examples in the paper, the description of the above examples is only used for helping to understand the method and core idea of the free space optical communication audio signal propagation demonstration device; meanwhile, for the general technical personnel in the field, the specific implementation mode and application range will be changed according to the idea of the free space optical communication audio signal propagation demonstration device, and the above is not understood as the limitation of the free space optical communication audio signal propagation demonstration device.

Claims

1. A free space optical communication audio signal propagation demonstration apparatus, characterized by, The demonstration device comprises a transmitting end and a receiving end; the transmitting end comprises a same-direction proportional amplification circuit, a direct current bias circuit, a reverse proportional amplification circuit, a reverse output circuit and a laser; the receiving end comprises an optical signal receiving circuit, an amplification module and an audio playing module; After the externally input audio signal is converted into an electric signal in the same-direction proportional amplification circuit, the electric signal is amplified in the audio signal frequency range; the amplified electric signal is input into the reverse proportional amplification circuit for reverse amplification, and the reverse proportional amplification circuit is also connected with the direct current bias circuit, which is used to ensure that the reverse amplified electric signal can be correctly amplified without distortion in the audio signal range; the reverse amplified electric signal is input into the reverse output circuit, which reversely amplifies the electric signal again in the audio signal frequency range, at this time, the electric signal has the same voltage direction as the input audio signal, and then the amplified electric signal is input into the laser, so that the laser carrying the audio signal is emitted, and the laser is emitted into the free space; the optical signal receiving circuit receives the laser in the free space and converts the optical signal into an electric signal, the electric signal is extracted by the active filter circuit, and then the electric signal is amplified by the amplification module, and the amplified electric signal is input into the audio playing module to output the audio signal.

2. The presentation device of claim 1, wherein, The input audio signal is applied to the non-inverting input end of the NE5532 chip in the same-direction proportional amplification circuit through resistance to amplify the electric signal in the audio signal frequency range.

3. The presentation device of claim 1, wherein, The direct current bias circuit adopts the NE5532 chip to ensure that the electric signal can be correctly amplified without distortion in the audio signal frequency range, and ensure that the working point is in the linear region of amplification.

4. The presentation device of claim 1, wherein, The amplified electric signal is applied to the inverting input end of the NE5532 chip in the reverse proportional amplification circuit through resistance to reversely amplify the electric signal in the audio signal frequency range.

5. The presentation device of claim 1, wherein, The reverse amplified electric signal is applied to the inverting input end of the NE5532 chip in the reverse output circuit through resistance to reversely amplify the electric signal again in the audio signal range.

6. The presentation device of claim 1, wherein, The optical signal receiving circuit comprises a PN photodiode, which converts the change of received light into the change of current by using the photosensitive property of the PN junction, and the optical signal is applied to the non-inverting input end of the NE5532 chip in the optical signal receiving circuit through resistance to realize the conversion of current and voltage.

7. The presentation device of claim 1, wherein, The amplification module adopts the TDA2030A digital power amplifier module to amplify the electric signal.

8. The presentation device of claim 1, wherein, The audio playing module adopts a 0.5W loudspeaker to output the audio signal.

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