CN215420246U - Stereo audio signal emission equipment circuit - Google Patents
Stereo audio signal emission equipment circuit Download PDFInfo
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- CN215420246U CN215420246U CN202121493271.7U CN202121493271U CN215420246U CN 215420246 U CN215420246 U CN 215420246U CN 202121493271 U CN202121493271 U CN 202121493271U CN 215420246 U CN215420246 U CN 215420246U
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Abstract
The utility model provides a stereo audio signal transmitting device circuit, which comprises an audio compression circuit, a stereo composite signal generating circuit, a singlechip, a set frequency oscillation and frequency modulation circuit and a power amplifying circuit, wherein stereo audio signals are input at the input end of the audio compression circuit, the output end of the audio compression circuit is connected with the input end of the stereo composite signal generating circuit, the output end of the stereo composite signal generating circuit is connected with the input end of the set frequency oscillation and frequency modulation circuit, the output end of the set frequency oscillation and frequency modulation circuit is connected with the input end of the power amplifying circuit, the singlechip is respectively connected with the second input end of the stereo composite signal generating circuit and the second input end of the set frequency oscillation and frequency modulation circuit, the set frequency oscillation and frequency modulation circuit modulates the stereo composite signals and the signals with the set frequency, and outputting the output to a power amplifying circuit. The utility model can effectively improve the signal-to-noise ratio of the audio signal.
Description
Technical Field
The present invention relates to a transmitter circuit, and more particularly, to a circuit for a stereo audio signal transmitting apparatus.
Background
The existing transmitter is generally a single-channel signal, and cannot transmit a stereo composite signal, so that a good tone quality effect cannot be achieved.
SUMMERY OF THE UTILITY MODEL
To solve the problems in the prior art, the present invention provides a stereo audio signal transmitting apparatus circuit.
The utility model comprises an audio compression circuit, a stereo composite signal generating circuit, a singlechip, a set frequency oscillation and frequency modulation circuit and a power amplifying circuit, wherein the input end of the audio compression circuit inputs stereo audio signals, the output end of the audio compression circuit is connected with the input end of the stereo composite signal generating circuit, the output end of the stereo composite signal generating circuit is connected with the input end of the set frequency oscillation and frequency modulation circuit, the output end of the set frequency oscillation and frequency modulation circuit is connected with the input end of the power amplifying circuit, the singlechip is respectively connected with the second input end of the stereo composite signal generating circuit and the second input end of the set frequency oscillation and frequency modulation circuit, the set frequency oscillation and frequency modulation circuit modulates the stereo composite signals and the signals with the set frequency and outputs the signals to the power amplifying circuit, and the power amplifying circuit processes the signals, reflected by the transmitting antenna.
The utility model is further improved, the set frequency oscillation and frequency modulation circuit generates an ultrahigh frequency UHF signal, the stereo audio signal transmitting equipment circuit also comprises a phase-locked loop control circuit, the output end of the phase-locked loop control circuit is connected with the input end of the set frequency oscillation and frequency modulation circuit, and the input end of the phase-locked loop control circuit is connected with the crystal oscillator output end of the singlechip.
The utility model is further improved, the phase-locked loop control circuit comprises a control chip IC5, wherein a pin 11 of the control chip IC5 is connected with a crystal oscillator output end of the singlechip and is used as an external input reference signal, an output end of a pin 3 of the control chip IC5 is connected with an input end of a set frequency oscillation and frequency modulation circuit, and a pin 1 of the control chip IC5 receives a feedback signal of the set frequency oscillation and frequency modulation circuit.
The utility model is further improved, the set frequency oscillation and frequency modulation circuit comprises a triode T12, the base electrode of the triode T12 is respectively connected with the pin 3 of a control chip IC5 of the phase-locked loop control circuit and the output end of the stereo composite signal generating circuit, the emitter electrode of the triode T12 is respectively connected with the pin 1 of a grounding resistor R41 and a control chip IC5, and the collector electrode of the triode T12 outputs the modulated UHF oscillation signal.
The utility model is further improved by including an audio filter circuit disposed between the audio compression circuit and the stereo multiplex signal generating circuit.
The utility model is further improved and also comprises a power supply circuit and a power switching circuit connected with the power supply circuit, wherein the power switching circuit regulates the output power of the power amplifying circuit.
The utility model is further improved, and the power amplifier further comprises a power switching switch SW1 connected with the power switching circuit, wherein the power switching circuit comprises a switching tube T2 and an adjustable resistor W3, wherein the control end of the switching tube T2 is connected with the power switching switch SW1, one end of the switching tube T2 is grounded, the other end of the switching tube T2 is connected with an adjustable end and a normally connected end of the adjustable resistor W3, and the other normally connected end of the adjustable resistor W3 provides power for the power amplifying circuit.
The utility model is further improved and also comprises a radio frequency RF amplifying circuit arranged between the set frequency oscillating and frequency modulating circuit and the power amplifying circuit.
The utility model is further improved, the power amplification module comprises a primary power amplification tube T15, a secondary power amplification tube T16 and a filtering matching module connected with the output end of the secondary power amplification tube T16, the base of the primary power amplification tube T15 is connected with the output end of the radio frequency RF amplification circuit, the emitter of the primary power amplification tube T15 is grounded, the base of the power amplification tube T16 is connected with the collector of the primary power amplification tube T15, the emitter of the power amplification tube T16 is grounded, the collector of the power amplification tube T16 is respectively connected with the output end of the power switching circuit and the filtering matching module, and the filtering matching module is used for filtering an output signal and adjusting output power so that the output power is consistent with the transmitting power of an antenna.
The utility model is further improved by further comprising an automatic level control circuit arranged between the audio compression circuit and the audio signal input end.
Compared with the prior art, the utility model has the beneficial effects that: the compression circuit is adopted, so that the noise in the wireless transmission process can be effectively reduced, the tone quality is purer, and the interference caused in the wireless transmission process can be greatly reduced by modulating the stereo signal into a set frequency; the automatic level control circuit can flexibly adjust the time delay, the limited amplitude and the like according to the requirements, and is convenient to apply; the normal work of the whole circuit is ensured, the potential burning possibility is avoided, and the input audio signal can reach the ideal adjustable range.
Drawings
FIG. 1 is a block diagram of the present invention;
FIG. 2 is a schematic diagram of the switch/key circuit of the present invention;
FIG. 3 is a schematic diagram of an automatic level control circuit;
FIG. 4 is a circuit diagram of an embodiment of an audio compression circuit;
FIG. 5 is a circuit schematic of another embodiment of an audio compression circuit;
FIG. 6 is a schematic diagram of an audio filter circuit;
FIG. 7 is a schematic diagram of a stereo composite signal generating circuit, a large power switching circuit, a small power switching circuit, and a power supply circuit;
FIG. 8 is a schematic diagram of a UHF oscillation and frequency modulation circuit and an RF amplification circuit;
FIG. 9 is a schematic diagram of a power amplification circuit;
FIG. 10 is a schematic diagram of a single chip circuit and a phase locked loop control circuit;
fig. 11 is a schematic diagram of a display circuit.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. As an embodiment of the present invention, this example raises the frequency of the input audio signal to a UHF transmission.
As shown in fig. 1, the present invention includes an automatic level control circuit, an audio compression circuit, a stereo composite signal generation circuit, a single chip microcomputer, a UHF oscillation and frequency modulation circuit, and a power amplification circuit, wherein an input end of the audio compression circuit is connected to an output end of the automatic level control circuit, an output end of the audio compression circuit is connected to an input end of the stereo composite signal generation circuit, an output end of the stereo composite signal generation circuit is connected to an input end of the UHF oscillation and frequency modulation circuit, an output end of the UHF oscillation and frequency modulation circuit is connected to an input end of the power amplification circuit, the single chip microcomputer is respectively connected to a second input end of the stereo composite signal generation circuit and a second input end of the UHF oscillation and frequency modulation circuit, the UHF oscillation and frequency modulation circuit modulates the stereo composite signal into a UHF oscillation signal and outputs the UHF oscillation signal to the power amplification circuit, and after being processed by the power amplifying circuit, the power amplifying circuit is reflected by the transmitting antenna.
The compression circuit is adopted in the embodiment, the time delay and the limited amplitude and the like can be flexibly adjusted according to requirements, the application is convenient, the noise in the wireless transmission process can be effectively reduced, and the tone quality is purer.
The present example also includes a switch/key input circuit and a display circuit, each of which is connected to the single chip microcomputer, the switch/key input circuit being configured to operate the transmitting device. The power amplifier further comprises a power circuit and a power switching circuit connected with the power circuit, wherein the power switching circuit adjusts the output power of the power amplifying circuit.
The phase-locked loop control circuit is connected with the UHF oscillation and frequency modulation circuit and used for controlling oscillation signals of the UHF oscillation circuit.
The present invention further includes an audio filter circuit disposed between the audio compression circuit and the stereo composite signal generating circuit, and preferably, the rear stage of the UHF oscillation and frequency modulation circuit further includes an RF (radio frequency) amplifier circuit, an input end of the RF amplifier circuit is connected to an output end of the UHF oscillation and frequency modulation circuit, and an output end of the RF amplifier circuit is connected to a power amplifier circuit of the rear stage.
As an embodiment of the utility model, the UHF frequency of the embodiment adopts 600-1000MHz, and because users in the UHF frequency range are very few, the modulated audio signal has small interference, thereby reducing the noise caused by the interference and greatly improving the signal quality. In addition, the original composite stereo signal is modulated into an ultrahigh frequency signal, so that the signal transmission efficiency is greatly improved, and the loss in the transmission process is reduced. Of course, the present example can also modulate the audio signal into other, less common frequency bands.
As shown in fig. 2, the switch/key circuit of this example includes a power switch SW1, channel adjusting switches SW3 and SW4, and a power switch SW 2.
As shown in fig. 3, the automatic level control circuit of this embodiment includes a sound input module, a clipping protection module, an operational amplifier module, a rectifier module, a filter module, and a level adjustment module, wherein, the sound input module is used for receiving input audio signals, the input end of the amplitude limiting protection module is connected with the output end of the sound input module, the output end of the amplitude limiting protection module is connected with the input end of the operational amplifier module, the output end of the operational amplifier module outputs the processed audio signal, the output end of the operational amplifier module is also connected with the input end of the rectifier module, the output end of the rectifier module is connected with the input end of the filter module, the output end of the filter module is connected with the input end of the level adjustment module, and the output end of the level adjusting module and the audio signal output by the output end of the amplitude limiting protection module are input to the input end of the operational amplifier module together. The audio signal amplified and output by the operational amplifier module is subjected to feedback adjustment, so that the finally output audio signal is within a certain amplitude range.
As an embodiment of the present invention, the sound input module of this embodiment includes an audio interface J1, the sound input module inputs stereo audio signals including left channel audio signals and right channel audio signals, a first signal output pin of the audio interface J1 outputs right channel audio signals, a second signal output pin of the audio interface J1 outputs left channel audio signals, and accordingly, the amplitude limiting protection module, the operational amplifier module, and the rectifier module each include two processing branches with the same structure, which are used to process two channels of audio signals respectively, and the output end of the rectifier module is output to the filter module for processing and then is output to the level adjustment module for adjustment as one channel of signal. If the signal is a single-channel signal, one-path signal processing can be directly set.
The amplitude limiting protection module of the embodiment comprises two double diodes D3 and D4 which are connected in series, wherein two ends of the double diode D3 are grounded, and the right channel audio signal output end of an audio interface J1 is connected in the middle, two ends of the double diode D4 are grounded, and the left channel audio signal output end of an audio interface J1 is connected in the middle. The voltage is set to be 5-8V in the example, and can be set to be other voltage ranges according to requirements.
The operational amplifier module of the embodiment comprises an operational amplifier IC1C and an operational amplifier IC1B, wherein the positive phase input end of the operational amplifier is connected with the output end of the amplitude limiting protection circuit through a resistor and a capacitor which are connected in series, the negative phase input end of the operational amplifier is grounded through a resistor and a capacitor which are connected in series, and the output end of the operational amplifier module is connected with the output end of the operational amplifier module through a series resistor.
The rectifying module can be a rectifier or more than 1 diode connected. The rectifying module of the embodiment also adopts double diodes D5 and D6 to rectify two paths of signals into direct-current signal voltage, wherein two diodes of the double diode D5 are connected in series, the anode is grounded, the cathode is connected with the input end of the level adjusting module, and the output end of the operational amplifier IC1C is connected between the two diodes; two diodes of the double diode D6 are connected in series, the anode is grounded, the cathode is connected with the input end of the level adjusting module, and the output end of the operational amplifier IC1B is connected between the two diodes.
The filtering module of this example is a polar capacitor C14, the anode of the polar capacitor C14 is connected to the cathode terminals of two double diodes D5 and D6, and the cathode of the polar capacitor C14 is grounded. The filter is used for filtering the direct current level signal and filtering noise.
The level adjustment module of this example includes triode T3-T6, wherein, triode T6 and T5 mirror image sets up, the base of triode T5 and T6 is connected, and connect the output of rectifier module, the collector of triode T5 and T6 is connected with the power, the emitter of triode T5 is connected with the base of triode T4, the emitter of triode T6 is connected with the base of triode T3, the emitter of triode T3 and the emitter of triode T4 are grounded respectively, the collector of triode T3 is connected with the input of the first signal processing branch of power amplifier module, the collector of triode T4 is connected with the input of the second signal processing branch of power amplifier module.
The working principle of the embodiment is as follows:
when the voltage signal output by the amplitude limiting circuit is large, for example, when the signal at the output end of the operational amplifier reaches 1.5V, the triodes T5 and T6 are conducted, high voltage is applied to the bases of the triodes T3 and T4 to enable the triodes T3 and T4 to be conducted, after the triodes T3 and T4 are conducted, the collectors are directly grounded, and a part of voltage is discharged according to the conduction quantity of the triodes T3 and T4, so that the output voltage signal is reduced. The conduction quantities of the triode T3 and the triode T4 are respectively controlled by the triodes T5 and T6, the conduction quantities of the triodes T5 and T6 are controlled by the output signals of the operational amplifier IC1C and IC1B, the larger the output signal is, the larger the discharged voltage is, the smaller the signal is, and the smaller the discharged voltage is, so that the automatic adjustment of the level is realized, and the level is stabilized within a certain range.
As shown in fig. 4 and fig. 5, the audio compression circuit of this embodiment is compatible with any audio compression circuit on the market, and this embodiment can use the mode of one audio compression chip + two-way operational amplifier of the first embodiment to process the left and right channels respectively, and can also use the second embodiment to set two compression processing chips IC19 and IC10 to perform compression processing respectively, and then output the compressed signals to the audio filter circuit of the subsequent stage. The two audio filtering circuits can also be used in combination, and the specific circuit is shown in fig. 6.
As shown in fig. 7, the stereo composite signal generating circuit of this embodiment includes a first input terminal and a second input terminal, two pins of the first input terminal are respectively input with the left channel audio signal and the right channel audio signal output by the audio filter circuit, the second input terminal is connected to the single chip, the 19KHz pilot signal and the 38KHz switching signal generated by the single chip are input, and the stereo composite signal generating circuit mixes the two signals to form a standard stereo composite signal.
The switch/key circuit of this example is provided with a power switch SW1, the power switch circuit includes a switch tube T2 and an adjustable resistor W3, wherein a control end of the switch tube T2 is connected to the power switch SW1, one end of the switch tube is grounded, the other end of the switch tube is connected to an adjustable end and a normally connected end of the adjustable resistor W3, and the other normally connected end of the adjustable resistor W3 provides power for a push tube of the filter amplifier circuit and a power amplifier tube of the power amplifier circuit. The power supply circuit is provided with an IC2 and an IC7 which are power supply voltage regulators.
As shown in fig. 10, the single chip microcomputer circuit of this embodiment includes a single chip microcomputer IC6 and a crystal oscillator Y1 having one end connected to a single chip microcomputer IC6, and the other end of the crystal oscillator Y1 is connected to a pin 11 of a control chip IC5 of the PLL control circuit, and is used as an external input reference signal. And then the frequency and the phase of the oscillation signal inside the loop are controlled by using an external input reference signal, the oscillation signal is output to the UHF oscillation circuit through a pin 3 of a control chip IC5, and a feedback signal of the UHF oscillation circuit is received through a pin 1.
As shown in fig. 8, the UHF oscillation and frequency modulation circuit of this embodiment includes a transistor T12, a base of the transistor T12 is respectively connected to pin 3 of a control chip IC5 of the pll control circuit and an output terminal of the stereo composite signal generation circuit, an emitter of the transistor T12 is respectively connected to pin 1 of a ground resistor R41 and a control chip IC5, and a collector of the transistor T12 outputs the modulated UHF oscillation signal. The RF amplifying circuit is used for amplifying the UHF oscillating signal modulated by the UHF oscillating and frequency modulating circuit, wherein T14 is a pushing pipe and used for pushing a power amplifying circuit at the rear stage.
As shown in fig. 9, the RF power amplifying module of this embodiment includes a first power amplifying transistor T15, a second power amplifying transistor T16, and a filter matching module connected to the output terminal of the second power amplifying transistor T16, wherein the base of the first power amplifying transistor T15 is connected to the output terminal of the RF amplifying circuit, the emitter of the first power amplifying transistor T15 is grounded, the base of the power amplifying transistor T16 is connected to the collector of the first power amplifying transistor T15, the emitter of the power amplifying transistor T16 is grounded, the collector of the power amplifying transistor T16 is connected to the output terminal of the power switching circuit and the filter matching module, respectively, and the filter matching module is configured to filter an output signal and adjust output power, so that the output power is consistent with the antenna transmission power.
The working principle of the utility model is as follows:
(1) after an audio signal (stereo) is input, firstly, the audio signal is processed through an automatic level control circuit to prevent the input audio signal from being overlarge;
(2) the audio signal is compressed in advance after being processed by the automatic level control circuit, and the receiving end can perform expansion processing to improve the signal-to-noise ratio of the audio signal;
(3) the stereo composite signal generating circuit mixes the pilot signal and the switch signal generated by the singlechip with the compressed audio signal output by the audio compression circuit to form a standard stereo composite signal;
(4) because the stereo composite signal has lower frequency, the UHF oscillation and frequency modulation circuit modulates the stereo composite signal at the front stage to the UHF frequency band, and then the signal is transmitted out through an antenna after being filtered and amplified.
(5) The frequency of the UHF oscillation signal is controlled by a phase-locked loop control circuit and a single chip microcomputer, so that on one hand, the frequency precision of the oscillation signal is ensured, and on the other hand, the transmission frequency is changed. The wireless transmitting equipment can change the transmitting frequency through the keys and display the current transmitting channel through the display circuit.
The above-described embodiments are intended to be illustrative, and not restrictive, of the utility model, and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Claims (10)
1. A stereo audio signal transmitting apparatus circuit, characterized in that: the stereo composite signal processing circuit comprises an audio compression circuit, a stereo composite signal generating circuit, a single chip microcomputer, a set frequency oscillation and frequency modulation circuit and a power amplifying circuit, wherein stereo audio signals are input at the input end of the audio compression circuit, the output end of the audio compression circuit is connected with the input end of the stereo composite signal generating circuit, the output end of the stereo composite signal generating circuit is connected with the input end of the set frequency oscillation and frequency modulation circuit, the output end of the set frequency oscillation and frequency modulation circuit is connected with the input end of the power amplifying circuit, the single chip microcomputer is respectively connected with the second input end of the stereo composite signal generating circuit and the second input end of the set frequency oscillation and frequency modulation circuit, the set frequency oscillation and frequency modulation circuit modulates the stereo composite signals and signals with set frequencies and outputs the signals to the power amplifying circuit, and the power amplifying circuit processes the signals, reflected by the transmitting antenna.
2. The stereo audio signal transmitting device circuit according to claim 1, characterized in that: the stereo audio signal transmitting equipment circuit also comprises a phase-locked loop control circuit, wherein the output end of the phase-locked loop control circuit is connected with the input end of the set frequency oscillation and frequency modulation circuit, and the input end of the phase-locked loop control circuit is connected with the crystal oscillator output end of the single chip microcomputer.
3. Stereo audio signal transmitting device circuit according to claim 2, characterized in that: the phase-locked loop control circuit comprises a control chip IC5, wherein a pin 11 of the control chip IC5 is connected with a crystal oscillator output end of a single chip microcomputer and used as an external input reference signal, an output end of a pin 3 of the control chip IC5 is connected with an input end of a set frequency oscillation and frequency modulation circuit, and a pin 1 of the control chip IC5 receives a feedback signal of the set frequency oscillation and frequency modulation circuit.
4. The stereo audio signal transmitting device circuit according to claim 3, characterized in that: the set frequency oscillation and frequency modulation circuit comprises a triode T12, the base electrode of the triode T12 is respectively connected with a control chip IC5 pin 3 of the phase-locked loop control circuit and the output end of the stereo composite signal generation circuit, the emitting electrode of the triode T12 is respectively connected with a grounding resistor R41 and a pin 1 of a control chip IC5, and the collecting electrode of the triode T12 outputs a modulated UHF oscillation signal.
5. The stereo audio signal transmitting device circuit according to claim 1, characterized in that: an audio filter circuit is also included and is disposed between the audio compression circuit and the stereo multiplex signal generating circuit.
6. The stereo audio signal transmitting device circuit according to claim 1, characterized in that: the power amplifier further comprises a power circuit and a power switching circuit connected with the power circuit, wherein the power switching circuit adjusts the output power of the power amplifying circuit.
7. Stereo audio signal transmitting device circuit according to claim 6, characterized in that: the power amplifier further comprises a power switching switch SW1 connected with the power switching circuit, wherein the power switching circuit comprises a switching tube T2 and an adjustable resistor W3, a control end of the switching tube T2 is connected with the power switching switch SW1, one end of the switching tube T2 is grounded, the other end of the switching tube T2 is connected with an adjustable end and a normally connected end of the adjustable resistor W3, and the other normally connected end of the adjustable resistor W3 provides a power supply for the power amplifying circuit.
8. The stereo audio signal transmitting device circuit according to claim 7, characterized in that: the radio frequency RF amplifying circuit is arranged between the set frequency oscillation and frequency modulation circuit and the power amplifying circuit.
9. The stereo audio signal transmitting device circuit according to claim 8, characterized in that: the power amplification module comprises a primary power amplification tube T15, a secondary power amplification tube T16 and a filtering matching module connected to the output end of the secondary power amplification tube T16, the base of the primary power amplification tube T15 is connected with the output end of the radio frequency RF amplification circuit, the emitter of the primary power amplification tube T15 is grounded, the base of the power amplification tube T16 is connected with the collector of the primary power amplification tube T15, the emitter of the power amplification tube T16 is grounded, the collector of the power amplification tube T16 is connected with the output end of the power switching circuit and the filtering matching module respectively, and the filtering matching module is used for filtering output signals and adjusting output power to enable the output power to be consistent with the transmitting power of an antenna.
10. The stereo audio signal transmitting device circuit according to claim 1, characterized in that: the audio compression circuit also comprises an automatic level control circuit arranged between the audio compression circuit and the audio signal input end.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121493271.7U CN215420246U (en) | 2021-07-01 | 2021-07-01 | Stereo audio signal emission equipment circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121493271.7U CN215420246U (en) | 2021-07-01 | 2021-07-01 | Stereo audio signal emission equipment circuit |
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| Publication Number | Publication Date |
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| CN215420246U true CN215420246U (en) | 2022-01-04 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202121493271.7U Active CN215420246U (en) | 2021-07-01 | 2021-07-01 | Stereo audio signal emission equipment circuit |
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| CN (1) | CN215420246U (en) |
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- 2021-07-01 CN CN202121493271.7U patent/CN215420246U/en active Active
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