CN203289520U - Talkback sidetone elimination circuit - Google Patents
Talkback sidetone elimination circuit Download PDFInfo
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- CN203289520U CN203289520U CN2013203678205U CN201320367820U CN203289520U CN 203289520 U CN203289520 U CN 203289520U CN 2013203678205 U CN2013203678205 U CN 2013203678205U CN 201320367820 U CN201320367820 U CN 201320367820U CN 203289520 U CN203289520 U CN 203289520U
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Abstract
The utility model discloses a talkback sidetone elimination circuit. The talkback sidetone elimination circuit comprises a local audio output end, a remote talkback audio mixing end and a sidetone elimination output end, an integrated operational amplifier, a first non-inverting input end resistor, a second non-inverting input end resistor, a inverting input end resistor, a feedback resistor and an isolation resistor. A subtracter is set up through the integrated operational amplifier, thereby stripping a local audio signal, and realizing a sidetone elimination function. The talkback sidetone elimination circuit isolates a transmission line from a transceiving circuit, enhances an anti-common-mode noise capability, a signal is transmitted after being amplified and boosted, line loss is reduced and the signal to noise ratio is improved at the same time, and thus the talkback sidetone elimination circuit has a very strong anti-noise capability, and is suitable for being used in occasions of relatively strong electromagnetic interference.
Description
Technical field
The utility model relates to the two-party-line system in electrical communication technology, particularly a kind of intercommunication anti-side-tone circuit.
Background technology
In the audio frequency intercommunication transmitting procedure in intercom system, be blended in the same circuit and transmit from the language audio signal of both direction, therefore, hear the sound of speech of oneself in the receiver of user Chang Huicong oneself, namely produce side tone effect.The existence of side tone effect, severe jamming the identification of user to the other side's voice.Therefore, for the problems of the prior art, improve the speech quality of two-party-line system, reduce the interference of sidetone to speech quality, in prior art, the anti-side-tone circuits that adopt are eliminated the sidetone in various audio communication systems more, especially in wired intercom and telephone system, use more general.
But anti-side-tone circuit of the prior art, because circuit only has single anti-sidetone function, therefore, while using in some stronger special occasions of electromagnetic interference, as: in the vehicle-mounted intercom system of subway, vehicle-mounted intercom system can be subject to stronger electromagnetic interference.Anti-side-tone circuit can cause and can't work due to electromagnetic interference, thereby can produce the excessive phenomenon of noise, finally make intercom system in the stronger occasion of electromagnetic interference in the intercommunication process, can't guarantee speech quality.
The utility model content
For defect of the prior art, the utility model provides a kind of intercommunication anti-side-tone circuit, thereby has solved in prior art, under the stronger occasion of electromagnetic interference, and the problem that in intercom system, anti-sidetone can't effectively be eliminated.
Therefore, the utility model provides a kind of intercommunication anti-side-tone circuit, comprise: local audio output, long-range intercommunication audio mix end and anti-sidetone output, wherein, comprising: integrated operational amplifier, the first in-phase input end resistance, the second in-phase input end resistance, inverting input resistance, feedback resistance and isolation resistance; The two ends of described isolation resistance, be connected with described local audio output and described long-range intercommunication audio mix end respectively; The in-phase input end of described integrated operational amplifier after described the first in-phase input end resistance of series connection, is connected with the power ground end, after described the second in-phase input end resistance of series connection, with described local audio output, is connected; The inverting input of described integrated operational amplifier, with the described inverting input resistance of connecting after, be connected with described long-range intercommunication audio mix end; Described feedback resistance is parallel between the output of described inverting input and described integrated operational amplifier, and this output is connected with described anti-sidetone output.
Wherein, also comprise: power amplification circuit, described power amplification circuit is connected with described local audio output.
Wherein, also comprise: isolating transformer, described isolating transformer comprises: primary side and secondary side, a utmost point of described primary side is connected with the local audio output, and another utmost point of described primary side is connected with ground wire.
Wherein, also comprise: can control attenuation units, the described attenuation units of controlling connects with, described the first in-phase input end resistance and described the second in-phase input end resistance respectively.
Wherein, described the second in-phase input end resistance is slide rheostat.
Wherein, also comprise: gain amplifying circuit, described gain amplifying circuit is connected with described anti-sidetone output.
Wherein, the resistance of described the first in-phase input end resistance is 10K Ω; The resistance of described the second in-phase input end resistance is 30K Ω; The resistance of described feedback resistance is 20K Ω; The resistance of described inverting input resistance is 10K Ω.
Wherein, the resistance of described isolation resistance is 30K Ω.
The utility model also provides a kind of talkback unit simultaneously, wherein, comprising: the intercommunication anti-side-tone circuit that provides in the utility model.
Compared with prior art, according to intercommunication anti-side-tone circuit of the present utility model, following advantage is arranged: the circuit that the utility model proposes, transmission line and transmission circuit are isolated, strengthen anti-common-mode noise ability.Transmit after the signal amplification is boosted, reduce line loss and improve simultaneously signal and noise ratio, therefore, improved the antijamming capability of anti-side-tone circuit.
Description of drawings
Fig. 1 is the conspectus of intercommunication anti-side-tone circuit in a kind of execution mode of the utility model;
Fig. 2 is that in a kind of execution mode of the utility model, the intercommunication anti-side-tone circuit comprises the conspectus that local audio amplifies;
Fig. 3 is in a kind of execution mode of the utility model, the conspectus of the intercommunication anti-side-tone circuit of tunable load;
Fig. 4 is in a kind of execution mode of the utility model, the conspectus of the intercommunication anti-side-tone circuit of another kind of tunable load.
Embodiment
Below in conjunction with accompanying drawing, utility model is described in further detail.Fig. 1 is the conspectus of intercommunication anti-side-tone circuit in a kind of execution mode of the utility model.As shown in Figure 1, the intercommunication anti-side-tone circuit in the utility model one embodiment, comprise being connected with local intercom system audio output local audio output I1; Be connected remote audio input I2 with long-range intercom system audio input end; In the line, audio signal from local audio output I1, with the audio signal from remote audio input I2, meet at long-range intercommunication audio mix end B point, anti-sidetone output O2 from I1+I2 after elimination I1, and further comprise: integrated operational amplifier U1, the first in-phase input end resistance R 3, the second in-phase input end resistance R 2, inverting input resistance R 4, feedback resistance R5 and isolation resistance R1.Wherein, the two ends of isolation resistance R1, be connected with local audio output I1 and long-range intercommunication audio mix end (B point) respectively; The in-phase input end "+" of integrated operational amplifier U1 after series connection the first in-phase input end resistance R 3, is connected with the power ground end, and after series connection the second in-phase input end resistance R 2, I1 is connected with the local audio output; The inverting input "-" of integrated operational amplifier U1, with the inverting input resistance R 4 of connecting after, be connected with long-range intercommunication audio mix end (B point); Feedback resistance R5 is parallel between the output (C point) of inverting input "-" and integrated operational amplifier U1, and this output is connected with anti-sidetone output O2.Thereby integrated operational amplifier U1 forms " subtracter " in circuit, in-phase input end "+" input signal (I1) and inverting input "-" input signal (I1+I2) are subtracted each other, and by the output (C point) of integrated operational amplifier U1, export, thereby realize separating the function of local signal (I1) from mixed signal (I1+I2), realize offseting the elimination of sidetone signal.
For the signal output that makes local audio output I1 can have some strength, therefore, be in a kind of execution mode of the utility model as Fig. 2, the intercommunication anti-side-tone circuit comprises shown in the conspectus that local audio amplifies, also comprise at local audio output I1 in above-mentioned circuit: power amplification circuit G1, this power amplification circuit is connected with local audio output I1, usually can select TDA2030A to realize.
Simultaneously, for making local audio output O1, has better anti-electromagnetic interference capability, also comprise in above-mentioned circuit: isolating transformer T1, its isolating transformer comprises: primary side, i.e. 1,2 end and secondary sides, i.e. 3,4 sides, primary side 1 end is connected with local audio output I1, and 2 ends of primary side are connected with ground wire.Thereby while making the outside output signal of local audio output, Single-end output is become balance output, greatly improve antijamming capability; (for example: 1: 36, corresponding voltage was than being 2.78Vrms: 100Vrms), usually boost, can improve efficiency of transmission and signal to noise ratio for no-load voltage ratio that simultaneously can be by the appropriate design transformer.
In conjunction with said structure, the operation principle that intercommunication anti-side-tone circuit in the utility model is described is: the intercommunication audio signal of local audio output I1 is carried out power amplification (namely, by power amplification circuit G1) after output to the A place, after being connected in series R1 again, isolate and boost being connected on transmission line by audio frequency transformer T1.Simultaneously, on transmission line except local voice signal (I1) is arranged, the other side's speech signal (I1+I2) in addition, be coupled to B place in figure by T1; This moment, B place was mixed signal (voice telecommunication of both direction number has), and the A point that power amplifier is exported can be considered as internal resistance be 0 point near-sightedly, the external signal of telecommunication will be absorbed, and only present the output signal (I1) of local audio output I1.Therefore B point signal (I1+I2) is deducted A point signal (I1), can separate the speech signal (I2) of remote audio, and the local voice signal (I1) that disappears.R2, R3, R4, R5 and U1 in figure (amplifier or audio frequency amplifier) have formed a subtracter, be used for to offset the native language acoustic that namely disappears, and are exported by the C point finally.
Due to the signal voltage that A point signal voltage is ordered greater than B, in order to mate, the resistance value that therefore needs to adjust R2, R3 is to obtain suitable decay, and R4, R5 resistance value ratio will affect the amplitude of anti-sidetone output, can be designed to flexibly amplify or decay.Wherein the choosing value of R2, R3, R4, R5 and U1 can be: the resistance of the first in-phase input end resistance R 3 is 10K Ω; The resistance of the second in-phase input end resistance R 2 is 30K Ω; The resistance of feedback resistance R5 is 20K Ω; The resistance of inverting input resistance R 4 is 10K Ω.The resistance of isolation resistance R1 is 30K Ω; Integrated operational amplifier U1 can select NE5532., by above-mentioned determined resistance, can make the operation of integrated operational amplifier U1, and the circuit overall performance is more stable.
For making above-mentioned intercommunication anti-side-tone circuit, in system applicable to multi-party inter-speaking, can regulate at any time for input load, therefore, in execution mode as a kind of in Fig. 3 the utility model, shown in the conspectus of the intercommunication anti-side-tone circuit of tunable load, also comprise: can control attenuation units C1, can control attenuation units C1 respectively with, described the first in-phase input end resistance R 3 and described the second in-phase input end resistance R 2 connect, wherein, can control attenuation units C1 can realize by embedded systems such as Programmable Logic Controllers.Also can increase controllable gain after C point output simultaneously and control, namely at anti-sidetone output O2, increase and connect gain amplifying circuit Z1.Thereby, with the overweight volume down minor issue that brings of compensating load.
As shown in Figure 4, in the intercommunication anti-side-tone circuit of above-mentioned tunable load, as less in the regulating frequency to load, the amplitude of accommodation is certain, it also can be set to slide rheostat with the second in-phase input end resistance R 2 on the line map basis of Fig. 2, thereby meets the adjusting to random load.
Simultaneously, also provide a kind of talkback unit in another kind of execution mode of the present utility model, this talkback unit has comprised intercommunication anti-side-tone circuit of the present utility model.
Above-described is only execution modes more of the present utility model.For the person of ordinary skill of the art, under the prerequisite that does not break away from the utility model creation design, can also make some distortion and improvement, these all belong to the protection range of utility model.
Claims (9)
1. intercommunication anti-side-tone circuit, comprise: local audio output, long-range intercommunication audio mix end and anti-sidetone output, it is characterized in that, comprising: integrated operational amplifier, the first in-phase input end resistance, the second in-phase input end resistance, inverting input resistance, feedback resistance and isolation resistance; The two ends of described isolation resistance, be connected with described local audio output and described long-range intercommunication audio mix end respectively; The in-phase input end of described integrated operational amplifier after described the first in-phase input end resistance of series connection, is connected with the power ground end, after described the second in-phase input end resistance of series connection, with described local audio output, is connected; The inverting input of described integrated operational amplifier, after the described inverting input resistance of series connection, be connected with described long-range intercommunication audio mix end; Described feedback resistance is parallel between the output of described inverting input and described integrated operational amplifier, and this output is connected with described anti-sidetone output.
2. circuit according to claim 1, is characterized in that, also comprises: power amplification circuit, described power amplification circuit is connected with described local audio output.
3. circuit according to claim 2, is characterized in that, also comprises: isolating transformer, and described isolating transformer comprises: primary side and secondary side, a utmost point of described primary side is connected with the local audio output, and another utmost point of described primary side is connected with ground wire.
4. circuit according to claim 1, is characterized in that, also comprises: can control attenuation units, the described attenuation units of controlling connects with, described the first in-phase input end resistance and described the second in-phase input end resistance respectively.
5. circuit according to claim 1, is characterized in that, described the second in-phase input end resistance is slide rheostat.
6. circuit according to claim 1, is characterized in that, also comprises: gain amplifying circuit, described gain amplifying circuit is connected with described anti-sidetone output.
7. circuit according to claim 1, is characterized in that, the resistance of described the first in-phase input end resistance is 10K Ω; The resistance of described the second in-phase input end resistance is 30K Ω; The resistance of described feedback resistance is 20K Ω; The resistance of described inverting input resistance is 10K Ω.
8. circuit according to claim 6, is characterized in that, the resistance of described isolation resistance is 30K Ω.
9. a talkback unit, is characterized in that, comprising: as the intercommunication anti-side-tone circuit in claim 1-7 any one.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2013203678205U CN203289520U (en) | 2013-06-25 | 2013-06-25 | Talkback sidetone elimination circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2013203678205U CN203289520U (en) | 2013-06-25 | 2013-06-25 | Talkback sidetone elimination circuit |
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| Publication Number | Publication Date |
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| CN203289520U true CN203289520U (en) | 2013-11-13 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN2013203678205U Expired - Fee Related CN203289520U (en) | 2013-06-25 | 2013-06-25 | Talkback sidetone elimination circuit |
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| CN (1) | CN203289520U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105072241A (en) * | 2015-07-31 | 2015-11-18 | 合肥赛为智能有限公司 | Anti-sidetone circuit of intercom system isolation transformer |
| CN105657193A (en) * | 2014-11-14 | 2016-06-08 | 周美杉 | Sidetone elimination technology based two-line Ethernet communication interface circuit |
| CN106792352A (en) * | 2016-12-22 | 2017-05-31 | 苏州华启智能科技有限公司 | Anti-side-tone circuit and apply its two-wire full duplex talkback unit |
-
2013
- 2013-06-25 CN CN2013203678205U patent/CN203289520U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105657193A (en) * | 2014-11-14 | 2016-06-08 | 周美杉 | Sidetone elimination technology based two-line Ethernet communication interface circuit |
| CN105072241A (en) * | 2015-07-31 | 2015-11-18 | 合肥赛为智能有限公司 | Anti-sidetone circuit of intercom system isolation transformer |
| CN105072241B (en) * | 2015-07-31 | 2018-01-19 | 合肥赛为智能有限公司 | A kind of intercom system isolating transformer anti-side-tone circuit |
| CN106792352A (en) * | 2016-12-22 | 2017-05-31 | 苏州华启智能科技有限公司 | Anti-side-tone circuit and apply its two-wire full duplex talkback unit |
| CN106792352B (en) * | 2016-12-22 | 2020-01-24 | 苏州华启智能科技有限公司 | Side-tone eliminating circuit and two-wire full duplex intercom device using same |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20131113 Termination date: 20160625 |
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| CF01 | Termination of patent right due to non-payment of annual fee |