CN208863057U - Stablize the Mic voicefrequency circuit of frequency response output - Google Patents
Stablize the Mic voicefrequency circuit of frequency response output Download PDFInfo
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- CN208863057U CN208863057U CN201821422025.0U CN201821422025U CN208863057U CN 208863057 U CN208863057 U CN 208863057U CN 201821422025 U CN201821422025 U CN 201821422025U CN 208863057 U CN208863057 U CN 208863057U
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Abstract
The utility model relates to a kind of Mic voicefrequency circuits of stable frequency response output, including external Microphone jack, the Differential Input and negative-feedback attenuator circuit of the first order, the filter network and voltage follower circuit of the second level and the amplifying circuit of the third level, the input terminal of external Microphone jack connection Differential Input and negative-feedback attenuator circuit, the output end of Differential Input and negative-feedback attenuator circuit connects the input terminal of filter network and voltage follower circuit, the input terminal of the output end of filter network and voltage follower circuit connection amplifying circuit, the output end of amplifying circuit draws the output end as Microphone audio input circuit, the output end is also the microphone input termi-nal of audio processor.The circuit can ensure that frequency response curve is very smooth in entire audio frequency range, can be realized and stablizes output frequency response, and also can guarantee extraordinary frequency response characteristic in low frequency.
Description
Technical field
The utility model relates to the Microphone audio input filter circuit of vehicle audio entertainment systems, especially for
Audio-frequency unit more particularly to a kind of vehicle audio entertainment systems stablize the Microphone audio input circuit of frequency response output.
Background technique
In recent years, the application of the speech communications such as bluetooth in automobile is more and more wider, in vehicle audio entertainment systems often at present
Microphone audio input filter circuit presence response unstable (different frequency lower frequency response variance range is big),
The problems such as low cut is big, distorted signals is serious.However client is also more next to the output requirement of vehicle audio entertainment systems voice
It is higher, it needs to have stable and preferably sound quality output under entire voice band (usually in 20Hz~20KHz), therefore must
Circuit design must be continuously improved to meet the design requirement of continuous improvement.
Utility model content
The purpose of this utility model is to provide a kind of Mic audio-frequency electrics that the stabilization frequency response for vehicle entertainment system exports
Road, the circuit can ensure that frequency response curve is very smooth in entire audio frequency range, can be realized and stablize output frequency response,
And it also can guarantee extraordinary frequency response characteristic in low frequency.
To achieve the goals above, the technical solution adopted in the utility model is a kind of Mic audio of stable frequency response output
Circuit, the filter network including external Microphone jack, the Differential Input of the first order and negative-feedback attenuator circuit, the second level
And the amplifying circuit of voltage follower circuit and the third level, external Microphone jack connection Differential Input and negative-feedback decaying electricity
The output end connection filter network of the input terminal on road, Differential Input and negative-feedback attenuator circuit and the input of voltage follower circuit
The input terminal of the output end connection amplifying circuit of end, filter network and voltage follower circuit, the output end of amplifying circuit, which is drawn, to be made
For the output end of Microphone audio input circuit, which is also the microphone input termi-nal of audio processor.
As a kind of improvement of the utility model, Differential Input and negative-feedback attenuator circuit (the following letter of the first order
" first order circuit ") be referred to as Microphone audio input circuit attenuation network comprising first resistor, second resistance,
Three resistance, the 4th resistance, first capacitor, the second capacitor, third capacitor, the first amplifier IC, one end of first resistor, second resistance
Draw input terminal (with the input terminal of Differential Input and negative-feedback attenuator circuit) as first order circuit, first resistor it is another
The non-inverting input terminal of the first amplifier IC of end connection, the other end of second resistance connect the inverting input terminal of the first amplifier IC, third
Resistance and first capacitor simultaneously connect the inverting input terminal that rear one end connects the first amplifier IC, and the other end connects 2V power supply, the 4th resistance
And second capacitor and access between the non-inverting input terminal and output end of the first amplifier IC after connecing, one end connection first of third capacitor
The power end of amplifier IC, other end ground connection, accesses 5V power supply+5VSW between third capacitor and the power end of the first amplifier IC,
The ground terminal of first amplifier IC is grounded, and the output end of the first amplifier IC is that the output end of first order circuit (with Differential Input and is born anti-
Present the output end of attenuator circuit).
As a kind of improvement of the utility model, the filter network and voltage follower circuit of the second level are (hereinafter referred to as
" second level circuit ") be Microphone audio input circuit filter network and voltage follow comprising the 5th resistance, the 6th
Resistance, the 7th resistance, the 8th resistance, the 9th resistance, the 4th capacitor, the 5th capacitor, the 6th capacitor, the second amplifier IC, the 5th electricity
Draw the input terminal (with the input terminal of filter network and voltage follower circuit) as second level circuit, the input terminal in one end of resistance
The output end of first order circuit is connect, other end ground connection, the 4th capacitance series are between the 5th resistance and the 6th resistance, the 6th resistance
One end access 2V power supply, between the 4th capacitor of an end Jie of the 5th capacitor and the 6th resistance, the other end connect the 6th capacitor
One end, the other end of the 6th capacitor connects the non-inverting input terminal of the second amplifier IC, the 5th capacitor of an end Jie of the 7th resistance
And the 6th between capacitor, the other end connects the inverting input terminal of the second amplifier IC, a termination 2V power supply of the 8th resistance, the other end
Connect the non-inverting input terminal of the second amplifier IC, the output end of a second amplifier IC of termination of the 9th resistance, other end ground connection, the second fortune
The inverting input terminal and output end for putting IC are shorted, and the output end of the second amplifier IC is the output end of second level circuit (with filtering net
The output end of network and voltage follower circuit).
As a kind of improvement of the utility model, the amplifying circuit (hereinafter referred to as " tertiary circuit ") of the third level is
The gain network of Microphone audio input circuit comprising the tenth resistance, eleventh resistor, twelfth resistor, the 13rd
Resistance, the 14th resistance, the 15th resistance, the 7th capacitor, third amplifier IC, one end of the tenth resistance are drawn as third level electricity
The input terminal (with the input terminal of amplifying circuit) on road, the input terminate the output end of second level circuit, another termination third amplifier
The non-inverting input terminal of IC, eleventh resistor connect between the non-inverting input terminal and inverting input terminal of third amplifier IC, twelfth resistor
One end access 2V power supply, the other end accesses the inverting input terminal of third amplifier IC, and thirteenth resistor connects the anti-of third amplifier IC
Between phase input terminal and output end, the output end of a termination third amplifier IC of the 14th resistance, other end ground connection, the 7th capacitor
It is serially connected between the output end and the 15th resistance of third amplifier IC, the 7th capacitor of termination of the 15th resistance, another termination
Enter 2V power supply, branch is drawn between the 7th capacitor and the 15th resistance as the output end of tertiary circuit (with amplifying circuit
Output end).
As a kind of improvement of the utility model, the first amplifier IC, the second amplifier IC, third amplifier IC are all made of type
Number be NCV2902DTBR2G amplifier IC.
As a kind of improvement of the utility model, in external Microphone jack and Differential Input and negative-feedback decaying electricity
Input capacitance is equipped between the input terminal on road.
As a kind of improvement of the utility model, the Differential Input and negative-feedback attenuator circuit of the first order are to inputting it
In audio signal have -16dB decaying.
As a kind of improvement of the utility model, the amplifying circuit of the third level is carried out to audio signal therein is inputted
It is amplified to -6.5dB.
As a kind of improvement of the utility model, the Microphone audio input circuit can be by 10Hz-20KHz
The gain control of frequency band audio signal arrives -6.4dB in -7.8dB.
Compared with the existing technology, the Microphone audio input circuit overall construction design of the utility model is ingenious, leads to
Setting attenuation network, filter network and gain network are crossed, has preferable filtering characteristic to the frequency content other than audio, also reaches
Stability contorting exports the purpose of frequency response, and the audio signal that the audio signal of the microphone of input circuit exports after processing is entire
Frequency response curve is very smooth in audio frequency range, also can guarantee extraordinary frequency response characteristic in low frequency, and
It is undistorted can to support that the Microphone signal of 4Vpp inputs.
Detailed description of the invention
Fig. 1 be the utility model proposes Microphone audio input circuit structural block diagram.
Fig. 2 is the Differential Input of the first order of the utility model and the circuit diagram of negative-feedback attenuator circuit.
Fig. 3 is the second level circuit of the utility model and the circuit diagram of tertiary circuit.
Fig. 4 be the utility model proposes Microphone audio input circuit output gain waveform.
Specific embodiment
In order to deepen to be further described with reference to the accompanying drawing to the utility model to the understanding and cognition of the utility model
And introduction.
As shown in Figure 1-3, a kind of Mic voicefrequency circuit that the stabilization frequency response for vehicle entertainment system exports, including it is external
Microphone jack EXT_MIC+ and EXT_MIC-, the first order Differential Input and negative-feedback attenuator circuit, the second level filter
The amplifying circuit of wave network and voltage follower circuit and the third level, external Microphone jack connection Differential Input and negative-feedback
The output end connection filter network and voltage follower circuit of the input terminal of attenuator circuit, Differential Input and negative-feedback attenuator circuit
The input terminal of the output end connection amplifying circuit of input terminal, filter network and voltage follower circuit, the output end of amplifying circuit draw
Out as the output end MIC_IN+ of Microphone audio input circuit, which is also that the microphone of audio processor is defeated
Enter end.The gain of 10Hz-20KHz frequency range can be controlled and arrive -6.4dB in -7.8dB by entire circuit network, and in passband model
The highly stable gain output of interior formation is enclosed, to reach audio input signal (the Microphone signal process input of high stable
Enter audio processor after processing of circuit).This Microphone audio input circuit can by the EMC test specification of Ford,
And it can support to arrive 4VPPIt is undistorted.
Wherein, the Differential Input of the first order and negative-feedback attenuator circuit are declining for Microphone audio input circuit
Subtract network comprising first resistor R3221, second resistance R3223,3rd resistor R3224, the 4th resistance R3220, first capacitor
C3225, the second capacitor C3228, third capacitor C3233, the first amplifier ICIC3200-A, first resistor R3221, second resistance
The input terminal as first order circuit is drawn in one end of R3223, and the other end of first resistor R3221 connects the first amplifier
The non-inverting input terminal of ICIC3200-A, the other end of second resistance R3223 connect the anti-phase input of the first amplifier ICIC3200-A
End, 3rd resistor R3224 and first capacitor C3225 simultaneously connect the inverting input terminal that rear one end connects the first amplifier ICIC3200-A,
The other end connects 2V power supply, the 4th resistance R3220 and the second capacitor C3228 and accesses the same of the first amplifier ICIC3200-A after connecing
Between phase input terminal and output end, one end of third capacitor C3233 connects the power end of the first amplifier ICIC3200-A, the other end
Ground connection accesses 5V power supply+5VSW, the first amplifier between third capacitor C3233 and the power end of the first amplifier ICIC3200-A
The ground terminal of ICIC3200-A is grounded, and the output end of the first amplifier ICIC3200-A is the output end of first order circuit.The first order
Differential Input and negative-feedback attenuator circuit can inhibit common mode interference and have certain inhibition and attenuation to DM EMI, also structure
At the low-pass filter (first order output as shown in Figure 4) of a 55KHz, there is the decaying of -16dB to input signal, simultaneously
There is isolation and inhibiting effect to noise.
The filter network and voltage follower circuit of the second level are the filter network of Microphone audio input circuit
And voltage follow comprising the 5th resistance R3231, the 6th resistance R3232, the 7th resistance R3227, the 8th resistance R3229, the 9th
Resistance R3234, the 4th capacitor C3237, the 5th capacitor C3240, the 6th capacitor C3229, the second amplifier ICIC3200-C, the 5th electricity
Input terminal of one end extraction of R3231 as second level circuit is hindered, which terminates the output end of first order circuit, another termination
Ground, the 4th capacitor C3237 are serially connected between the 5th resistance R3231 and the 6th resistance R3232, a termination of the 6th resistance R3232
Enter 2V power supply, between an end Jie the 4th capacitor C3237 and the 6th resistance R3232 of the 5th capacitor C3240, other end connection the
One end of six capacitor C3229, the other end of the 6th capacitor C3229 connect the non-inverting input terminal of the second amplifier ICIC3200-C, the
Between an end Jie the 5th capacitor C3240 and the 6th capacitor C3229 of seven resistance R3227, the other end connects the second amplifier
The inverting input terminal of ICIC3200-C, a termination 2V power supply of the 8th resistance R3229, the second amplifier ICIC3200-C of another termination
Non-inverting input terminal, the 9th resistance R3234 one termination the second amplifier ICIC3200-C output end, the other end ground connection, second
The inverting input terminal and output end of amplifier ICIC3200-C is shorted, and the output end of the second amplifier ICIC3200-C is second level circuit
Output end.In the filter network and voltage follower circuit of the second level, the 6th resistance R3232, the 8th resistance R3229, the 4th
Capacitor C3237, the 5th capacitor C3240, the 6th capacitor C3229 together constitute the high-pass filter of a 10Hz, the second amplifier
Noise (second level output as shown in Figure 4) is further isolated as voltage follower in ICIC3200-C.In addition, the second level
Filter network filters out the low frequency part of 0-10Hz, and the bandpass filter of 10Hz-50KHz is formed with prime.
The amplifying circuit of the third level is the gain network of Microphone audio input circuit comprising the tenth resistance
R3226, eleventh resistor R3235, twelfth resistor R3236, thirteenth resistor R3239, the 14th resistance R3238, the 15th
One end extraction of resistance R3272, the 7th capacitor C3234, third amplifier ICIC3200-D, the tenth resistance R3226 are used as the third level
The input terminal of circuit, the input terminate the output end of second level circuit, and another termination third amplifier ICIC3200-D's is same mutually defeated
Enter end, eleventh resistor R3235 connects between the non-inverting input terminal and inverting input terminal of third amplifier ICIC3200-D, the 12nd electricity
2V power supply is accessed in the one end for hindering R3236, and the other end accesses the inverting input terminal of third amplifier ICIC3200-D, thirteenth resistor
R3239 connects between the inverting input terminal and output end of third amplifier ICIC3200-D, a termination third of the 14th resistance R3238
The output end of amplifier ICIC3200-D, other end ground connection, the 7th capacitor C3234 are serially connected in the output of third amplifier ICIC3200-D
Between end and the 15th resistance R3272, a 7th capacitor C3234 of termination of the 15th resistance R3272, the other end accesses 2V electricity
Output end of the branch as tertiary circuit is drawn in source between the 7th capacitor C3234 and the 15th resistance R3272.The third level
Amplifying circuit has amplification to signal, and the signal of original decaying -16db is increased to -6.5dB (third as shown in Figure 4
Grade output), thus by MIC input signal overall attenuation -6.4dB.
Preferably, the first amplifier ICIC3200-A, the second amplifier ICIC3200-C, third amplifier ICIC3200-D are equal
Using the amplifier IC of model NCV2902DTBR2G.
In addition, being equipped between external Microphone jack and the input terminal of Differential Input and negative-feedback attenuator circuit defeated
Enter capacitance.
The Differential Input and negative-feedback attenuator circuit of the first order to audio signal therein is inputted there is -16dB to decline
Subtract.
The amplifying circuit of the third level is amplified to audio signal therein is inputted to -6.5dB.
The Microphone audio input circuit can by the gain of 10Hz-20KHz frequency band audio signal control-
7.8dB to -6.4dB.
Technological means disclosed in the utility model is not limited only to technological means disclosed in above embodiment, also
Including technical solution consisting of any combination of the above technical features.It should be pointed out that for the ordinary skill of the art
For personnel, without departing from the principle of this utility model, several improvements and modifications can also be made, these are improved and profit
Decorations are also considered as the protection scope of the utility model.
Claims (9)
1. a kind of Mic voicefrequency circuit of stable frequency response output, it is characterised in that: including external Microphone jack, the first order
Differential Input and negative-feedback attenuator circuit, the filter network of the second level and voltage follower circuit and the third level amplifying circuit,
The input terminal of external Microphone jack connection Differential Input and negative-feedback attenuator circuit, Differential Input and negative-feedback decaying electricity
The output end of the output end connection filter network on road and the input terminal of voltage follower circuit, filter network and voltage follower circuit connects
The input terminal of amplifying circuit is connect, the output end of amplifying circuit draws the output end as Microphone audio input circuit, should
Output end is also the microphone input termi-nal of audio processor.
2. stablizing the Mic voicefrequency circuit of frequency response output as described in claim 1, which is characterized in that the difference of the first order
Input and negative-feedback attenuator circuit include first resistor, second resistance, 3rd resistor, the 4th resistance, first capacitor, the second electricity
Appearance, third capacitor, the first amplifier IC, one end extraction of first resistor, second resistance is as Differential Input and negative-feedback decaying electricity
The input terminal on road, the other end of first resistor connect the non-inverting input terminal of the first amplifier IC, the other end connection of second resistance the
The inverting input terminal of one amplifier IC, 3rd resistor and first capacitor simultaneously connect the inverting input terminal that rear one end connects the first amplifier IC,
The other end connects 2V power supply, the 4th resistance and the second capacitor and access after connecing the first amplifier IC non-inverting input terminal and output end it
Between, one end of third capacitor connects the power end of the first amplifier IC, other end ground connection, in the electricity of third capacitor and the first amplifier IC
5V power supply is accessed between source, the ground terminal ground connection of the first amplifier IC, the output end of the first amplifier IC is Differential Input and negative-feedback
The output end of attenuator circuit.
3. stablizing the Mic voicefrequency circuit of frequency response output as claimed in claim 2, which is characterized in that the filtering of the second level
Network and voltage follower circuit include the 5th resistance, the 6th resistance, the 7th resistance, the 8th resistance, the 9th resistance, the 4th capacitor,
5th capacitor, the 6th capacitor, the second amplifier IC, one end of the 5th resistance are drawn as the defeated of filter network and voltage follower circuit
Enter end, which terminates the output end of first order circuit, and other end ground connection, the 4th capacitance series are in the 5th resistance and the 6th resistance
Between, 2V power supply, between the 4th capacitor of an end Jie of the 5th capacitor and the 6th resistance, the other end are accessed in one end of the 6th resistance
One end of the 6th capacitor is connected, the other end of the 6th capacitor connects the non-inverting input terminal of the second amplifier IC, one end of the 7th resistance
It connects between the 5th capacitor and the 6th capacitor, the other end connects the inverting input terminal of the second amplifier IC, a termination of the 8th resistance
2V power supply, the non-inverting input terminal of the second amplifier IC of another termination, the output end of a second amplifier IC of termination of the 9th resistance are another
End ground connection, the inverting input terminal and output end of the second amplifier IC are shorted, and the output end of the second amplifier IC is filter network and voltage
Follow the output end of circuit.
4. stablizing the Mic voicefrequency circuit of frequency response output as claimed in claim 3, which is characterized in that the amplification of the third level
Circuit includes the tenth resistance, eleventh resistor, twelfth resistor, thirteenth resistor, the 14th resistance, the 15th resistance, the 7th
The input terminal as amplifying circuit is drawn in capacitor, third amplifier IC, one end of the tenth resistance, which terminates second level circuit
Output end, the non-inverting input terminal of another termination third amplifier IC, eleventh resistor connect the non-inverting input terminal of third amplifier IC and anti-
Between phase input terminal, one end access 2V power supply of twelfth resistor, the inverting input terminal of other end access third amplifier IC, the tenth
Three resistance connect between the inverting input terminal and output end of third amplifier IC, the output of a termination third amplifier IC of the 14th resistance
End, other end ground connection, the 7th capacitance series are between the output end and the 15th resistance of third amplifier IC, and the one of the 15th resistance
The 7th capacitor is terminated, the other end accesses 2V power supply, and branch is drawn between the 7th capacitor and the 15th resistance as amplifying circuit
Output end.
5. stablizing the Mic voicefrequency circuit of frequency response output as claimed in claim 4, which is characterized in that the first amplifier IC, the
Two amplifier IC, third amplifier IC are all made of the amplifier IC of model NCV2902DTBR2G.
6. stablizing the Mic voicefrequency circuit of frequency response output as claimed in claim 5, which is characterized in that in external Microphone
Input capacitance is equipped between the input terminal of jack and Differential Input and negative-feedback attenuator circuit.
7. stablizing the Mic voicefrequency circuit of frequency response output as claimed in claim 6, which is characterized in that the difference of the first order
Input and negative-feedback attenuator circuit have the decaying of -16dB to input audio signal therein.
8. stablizing the Mic voicefrequency circuit of frequency response output as claimed in claim 7, which is characterized in that the amplification of the third level
Circuit is amplified to audio signal therein is inputted to -6.5dB.
9. stablizing the Mic voicefrequency circuit of frequency response output as claimed in claim 8, which is characterized in that the Microphone
The gain of 10Hz-20KHz frequency band audio signal can be controlled and arrive -6.4dB in -7.8dB by audio input circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821422025.0U CN208863057U (en) | 2018-08-31 | 2018-08-31 | Stablize the Mic voicefrequency circuit of frequency response output |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821422025.0U CN208863057U (en) | 2018-08-31 | 2018-08-31 | Stablize the Mic voicefrequency circuit of frequency response output |
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| CN208863057U true CN208863057U (en) | 2019-05-14 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108924704A (en) * | 2018-08-31 | 2018-11-30 | 延锋伟世通电子科技（南京）有限公司 | Vehicle entertainment system stablizes the Microphone audio input circuit of frequency response output |
-
2018
- 2018-08-31 CN CN201821422025.0U patent/CN208863057U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108924704A (en) * | 2018-08-31 | 2018-11-30 | 延锋伟世通电子科技（南京）有限公司 | Vehicle entertainment system stablizes the Microphone audio input circuit of frequency response output |
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