CN206894870U - Audio decoding apparatus and its audio output circuit - Google Patents
Audio decoding apparatus and its audio output circuit Download PDFInfo
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- CN206894870U CN206894870U CN201720339321.3U CN201720339321U CN206894870U CN 206894870 U CN206894870 U CN 206894870U CN 201720339321 U CN201720339321 U CN 201720339321U CN 206894870 U CN206894870 U CN 206894870U
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Abstract
The utility model belongs to audio decoding techniques field, more particularly to a kind of audio decoding apparatus and its audio output circuit, wherein, the audio output circuit includes low-pass filtering module, impedance conversion module, the audio output circuit of buffer module and audio signal output module, filtered audio signal is exported to impedance conversion module by low-pass filtering module, impedance conversion module enters row buffering to filtered audio signal and converted with impedance, audio signal after output transform is to buffer module, buffer module carries out buffered to the audio signal after conversion, the audio signal after buffering is exported to audio signal amplification module, so as to output low noise, the audio signal of low distortion.
Description
Technical field
The utility model belongs to audio decoding techniques field, more particularly to a kind of audio decoding apparatus and its audio output electricity
Road.
Background technology
Decoder is a kind of digital analog converter, also known as DAC (Digital to analog converter)；It is one
The equipment that kind converts digital signals into analog signal by the form of curtage；CD player, the DVD usually used as us
The equipment such as machine, portable player, TV, mobile phone all carry decoder, because only that the D/A switch work(for passing through decoder
Can, we could see video image from these equipment and hear sound.Script can not be seen and heard by decoder
Data signal is converted to the analog signal for being available for people to identify；In audio frequency apparatus, decoder equally plays vital effect,
During analog signal is converted into from data signal, the quality of decoder directly determines the matter of the analog signal of output
Amount, while also determine final sound effect；Therefore, decoder is better, and obtained sound effect is better.
With the high speed development of multimedia and internet, people are to voice data network transmission and the requirement of audio tonequality
More and more higher, it is desirable to while the characteristics of voice data dynamic range is big is retained, accomplish as far as possible undistorted or meet human ear
The selective distortion of auditory properties, therefore, how to ensure that extremely low noise and distortion performance just design various sounds into people
The most direct purpose of frequency coding circuit.
At present, decoder of the prior art can not play high definition PCM music and Lossless Compression music, and it is only limitted to damage
The MP3 of compression and its similar style music file, because this music file is significantly compressed, cause the audio-frequency noise played
Greatly, the distortion factor is high.
The content of the invention
The purpose of this utility model is to provide a kind of audio decoding apparatus and its audio output circuit, it is intended to solves existing
The technical problem that the audio-frequency noise of technology insurmountable decoder output is big, the distortion factor is high.
The utility model is achieved in that a kind of audio output circuit of audio decoding apparatus, including：LPF mould
Block, impedance conversion module, buffer module and audio signal amplification module, the low-pass filtering module output end connection described in
The input of impedance conversion module, the output end of the impedance conversion module connects the input of the buffer module, described slow
The output end of die block connects the input of the audio signal amplification module；
The low-pass filtering module includes the first low-pass filter circuit and the second low-pass filter circuit, first low pass filtered
Wave circuit is used to carry out LPF to the simulated audio signal received, and output frequency value is less than the first sound of predeterminated frequency value
Frequency signal；Second low-pass filter circuit is used to carry out LPF, output frequency value to the simulated audio signal received
Less than the second audio signal of predeterminated frequency value；
The impedance conversion module includes the first impedance inverter circuit and the second impedance inverter circuit, and first impedance becomes
The input for changing circuit connects the output end of first low-pass filter circuit, and the input of second impedance inverter circuit connects
Connect the output end of second low-pass filter circuit；
First impedance inverter circuit is used to carry out first audio signal that receives impedance conversion, output the
Three audio signals；Second impedance inverter circuit is used to carry out impedance conversion to second audio signal received, defeated
Go out the 4th audio signal；
The buffer module includes the first buffer circuit and the second buffer circuit, and the input of first buffer circuit connects
The output end of first impedance inverter circuit is connect, the input of second buffer circuit connects the second impedance conversion electricity
The output end on road；
First buffer circuit is used to carry out buffered to the 3rd audio signal received, exports the five notes of traditional Chinese music
Frequency signal；Second buffer circuit is used to carry out buffered to the 4th audio signal received, exports the 6th sound
Frequency signal；
The audio signal amplification module includes Earphone Amplifier integrated chip, and the output end of first buffer circuit connects
The first pin of the Earphone Amplifier integrated chip is connect, the output end of second buffer circuit connects the Earphone Amplifier
The second pin of integrated chip, the audio signal amplification module are used for the fifth audio signal and the 6th sound to receiving
Frequency signal carries out fidelity enhanced processing, and exports final audio signal respectively.
Another object of the present utility model, which also resides in, provides a kind of audio decoding apparatus, including：It is digital audio receiver, more
The audio output circuit of path multiplexer, decoder and audio decoding apparatus；The output end connection of the digital audio receiver
The input of the multiplexer, the output end of the multiplexer connect the output end of the decoder, the decoding
First output end of device connects the input of first low-pass filter circuit, described in the second output end connection of the decoder
The input of second low pass filter；
The digital audio receiver is used to receive multiple digital audio and video signals, and the multiple digital audio and video signals are defeated
Go out to the multiplexer；
The multiplexer is used to be synthesized the multiple digital audio and video signals received, exports individual digit
Audio signal；
The decoder is used to digital audio and video signals being converted into simulated audio signal, and the simulated audio signal is defeated
Go out to the first low-pass filter circuit and the second low-pass filter circuit.
In the utility model, by audio decoding apparatus using include low-pass filtering module, impedance conversion module,
The audio output circuit of buffer module and audio signal output module, filtered audio signal is exported by low-pass filtering module
To impedance conversion module, impedance conversion module enters row buffering to filtered audio signal and converted with impedance, after output transform
For audio signal to buffer module, buffer module carries out buffered to the audio signal after conversion, and the audio after output buffers is believed
Number to audio signal amplification module, so as to output low noise, the audio signal of low distortion.
Brief description of the drawings
Fig. 1 is the function structure chart of the audio output circuit for the audio decoding apparatus that the utility model embodiment is provided；
Fig. 2 is another module knot of the audio output circuit for the audio decoding apparatus that the utility model embodiment is provided
Composition；
Fig. 3 is the circuit structure diagram of the first low-pass filter circuit shown in Fig. 2；
Fig. 4 is the circuit structure diagram of the second low-pass filter circuit shown in Fig. 2；
Fig. 5 is the circuit structure diagram of the first impedance inverter circuit shown in Fig. 2；
Fig. 6 is the circuit structure diagram of the second impedance inverter circuit shown in Fig. 2；
Fig. 7 is the circuit structure diagram of the first buffer circuit shown in Fig. 1；
Fig. 8 is the circuit structure diagram of the second buffer circuit shown in Fig. 1；
Fig. 9 is the function structure chart for the audio decoding apparatus that the utility model embodiment is provided.
Embodiment
In order that the purpose of this utility model, technical scheme and advantage are more clearly understood, below in conjunction with accompanying drawing and implementation
Example, the utility model is further elaborated.It should be appreciated that specific embodiment described herein is only explaining
The utility model, it is not used to limit the utility model.
Fig. 1 shows the modular structure of the audio output circuit of above-mentioned audio decoding apparatus, for convenience of description, only shows
The part related to the utility model embodiment, details are as follows：
Audio output circuit 1 includes：Low-pass filtering module 10, impedance conversion module 20, buffer module 30 and audio letter
Number amplification module 40, the input of the output end connection impedance conversion module 20 of low-pass filtering module 10, impedance conversion module 20
Output end connection buffer module 30 input, the input of the output end connection audio signal amplification module 40 of buffer module 30
End.
Low-pass filtering module 10 includes the first low-pass filter circuit 101 and the second low-pass filter circuit 102, the first low pass filtered
Wave circuit 101 is used to carry out the simulated audio signal that receives LPF, and output frequency value is less than the of predeterminated frequency value
One audio signal；Second low-pass filter circuit 102 is used to carry out LPF, output frequency to the simulated audio signal received
Second audio signal of the value less than predeterminated frequency value.
Impedance conversion module 20 includes the first impedance inverter circuit 201 and the second impedance inverter circuit 202, and the first impedance becomes
The input for changing circuit 201 connects the output end of the first low-pass filter circuit 101, the input of the second impedance inverter circuit 202
Connect the output end of the second low-pass filter circuit 102.
First impedance inverter circuit 201 is used to carry out impedance conversion to the first audio signal received, exports the 3rd sound
Frequency signal；Second impedance inverter circuit 202 is used to carry out impedance conversion to the second audio signal received, exports the 4th audio
Signal.
Buffer module 30 includes the first buffer circuit 301 and the second buffer circuit 302, the input of the first buffer circuit 301
The output end of the first impedance inverter circuit 201 of end connection, the input of the second buffer circuit 302 connect the second impedance inverter circuit
202 output end.
First buffer circuit 301 is used to carry out the 3rd audio signal received buffered, output fifth audio letter
Number；Second buffer circuit 302 is used to carry out buffered to the 4th audio signal received, exports the 6th audio signal.
Audio signal amplification module 40 includes Earphone Amplifier integrated chip, the output end connection of the first buffer circuit 301
First pin of Earphone Amplifier integrated chip, the output end connection Earphone Amplifier integrated chip of the second buffer circuit 302
Second pin, audio signal amplification module 40 are used to put the fifth audio signal received and the 6th audio signal progress fidelity
Big processing, and final audio signal is exported respectively.
Low-pass filtering module 10 filters out the audio signal outside predeterminated frequency, exports filtered audio signal.
Impedance conversion module 20 enters row buffering and impedance conversion, the sound after output impedance conversion to filtered audio signal
Frequency signal.
Buffer module 30 carries out buffered to the audio signal after conversion, exports the audio signal after buffering.
Audio signal amplification module 40 is amplified to the audio signal after buffering, output low noise, the sound of low distortion
Frequency signal.
In the utility model embodiment, include low-pass filtering module, impedance change by being used in audio decoding apparatus
The audio output circuit of block, buffer module and audio signal output module is changed the mold, is exported by low-pass filtering module filtered
Audio signal is to impedance conversion module, and impedance conversion module enters row buffering to filtered audio signal and converted with impedance, output
Audio signal after conversion is to buffer module, and buffer module carries out buffered to the audio signal after conversion, after output buffers
Audio signal to audio signal amplification module, so as to output low noise, the audio signal of low distortion.
Fig. 2 shows another modular structure of the audio output circuit of above-mentioned audio decoding apparatus, for convenience of description,
The part related to the utility model embodiment is illustrate only, details are as follows：
Audio output circuit 1 also includes interface module 50, the output end connection interface module of the first low-pass filter circuit 101
50 first input end, the second input of the output end connection interface module 50 of the second low-pass filter circuit 102, interface module
50 the first output end connects the input of the first impedance inverter circuit 201, the second output end connection second of interface module 50
The input of impedance inverter circuit 202.
In the utility model embodiment, by interface module connect the first low-pass filter circuit, the second bandpass filter circuit,
First impedance inverter circuit and the second impedance inverter circuit so that realize high-speed traffic between four circuits.
Fig. 3 shows the circuit structure of the first low-pass filter circuit, for convenience of description, illustrate only and the utility model
The related part of embodiment, details are as follows：
First low-pass filter circuit 101 includes：Resistance R59, resistance R60, resistance R61, resistance R64, resistance R72, resistance
R73, resistance R77, electric capacity C114, electric capacity C115, electric capacity C116, electric capacity C121, electric capacity C128, electric capacity C129, low noise operational
Amplifier U26-B, first voltage source+12V, the second voltage source -12V.
Resistance R60 first end is connected with resistance R59 first end, resistance R61 first end, electric capacity C116 first end
Connecing, resistance R61 the second end is connected with electric capacity C114 first end, low noise operational amplifier U26-B positive input terminal 3,
Low noise operational amplifier U26-B positive power source terminal 8 is connected to first voltage source+12V with electric capacity C115 first end；Resistance
R72 first end is connected with resistance R73 first end, resistance R77 first end, electric capacity C121 first end, resistance R73's
Second end is connected with electric capacity C128 first end, low noise operational amplifier U26-B negative input end 2, and low noise operational is put
Big device U26-B negative power end 4 and electric capacity C128 first end is connected to the second voltage source -12V；Resistance R77 the second end with
Electric capacity C128 the second end, resistance R64 first end, low noise operational amplifier U26-B output end 1 are connected, resistance R64
The second end connection interface module 50 first input end；Resistance R59 the second end, electric capacity C114 the second end, electric capacity C115
The second end, electric capacity C116 the second end, electric capacity C121 the second end, electric capacity C129 the second end be grounded.
Fig. 4 shows the circuit structure of the second low-pass filter circuit, for convenience of description, illustrate only and the utility model
The related part of embodiment, details are as follows：
Second low-pass filter circuit 102 includes：Resistance R86, resistance R87, resistance R88, resistance R91, resistance R96, resistance
R97, resistance R100, electric capacity C136, electric capacity C137, electric capacity C139, electric capacity C145, low noise operational amplifier U26-A；
Resistance R87 first end is connected with resistance R86 first end, resistance R88 first end, electric capacity C137 first end
Connect, resistance R88 the second end is connected with electric capacity C136 first end, low noise operational amplifier U26-A positive input terminal 5；
Resistance R96 first end is connected with electric capacity C139 first end, resistance R97 first end, resistance R100 first end, resistance
R97 the second end is connected with electric capacity C145 first end, low noise operational amplifier U26-A negative input end 6；Resistance
R100 the second end and electric capacity C145 the second end, resistance R91 first end, low noise operational amplifier U26-A output end 7
It is connected, the second input of resistance R91 the second end connection interface module 50；Resistance R86 the second end, the of electric capacity C136
Two ends, electric capacity C137 the second end, electric capacity C139 the second end are grounded.
LPF (Low-pass filter) is a kind of filter type, and rule can be normal through for low frequency signal, and surpasses
The high-frequency signal for crossing setting critical value is then blocked, weakened.But barrier, the amplitude that weakens then can according to different frequencies and
Different filter (purpose) and change.First low-pass filter circuit and the second LPF electricity in above-mentioned low-pass filtering module
The amplifier model used in road is identical, and this amplifier is customization amplifier, coordinates other components in circuit, and realization filters out default frequency
Other audio signals outside rate value.
Fig. 5 shows the circuit structure of the first impedance inverter circuit, for convenience of description, illustrate only and the utility model
The related part of embodiment, details are as follows：
First impedance inverter circuit 201 includes：Resistance R65, resistance R66, resistance R80, resistance R106, resistance R108, electricity
Hold C131, electric capacity C133, electric capacity C148, electric capacity C113, amplifier U25-B.
The first output end connection resistance R106 of interface module 50 first end, resistance R106 the second end and electric capacity C148
First end, resistance R108 first end, amplifier U25-B positive input terminal 3 be connected, amplifier U25-B positive power source terminal 8 and electricity
The first end for holding C113 is connected to first voltage source+12V；Resistance R65 first end and electric capacity C131 first end, resistance R80
First end, amplifier U25-B negative input end 2 be connected, the first end of amplifier U25-B negative power end 4 and electric capacity C133 connects
It is connected to the second voltage source -12V；Electric capacity C131 the second end passes through electricity with resistance R80 the second end, amplifier U25-B output end 1
Hinder the input of R66 connections the first buffer circuit 301, resistance R65 the second end, electric capacity C148 the second end, resistance R108
Second end, electric capacity C133 the second end, electric capacity C113 the second end are grounded.
Fig. 6 shows the circuit structure of the second impedance inverter circuit, for convenience of description, illustrate only and the utility model
The related part of embodiment, details are as follows：
Second impedance inverter circuit 202 includes：Resistance R92, resistance R107, resistance R109, resistance R115, resistance R62, electricity
Hold C149, electric capacity C157, amplifier U27-A.
The second output end connection resistance R109 of interface module 50 first end, resistance R109 the second end and electric capacity C157
First end, resistance R115 first end, amplifier U27-A positive input terminal 5 be connected；Resistance R92 first end and electric capacity
C149 first end, resistance R107 first end, amplifier U27-A negative input end 6 are connected；Electric capacity C149 the second end and electricity
Resistance R107 the second end, amplifier U27-A output end 7 are connected to the input of the second buffer circuit 302, electricity by resistance R62
Resistance R92 the second end, electric capacity C157 the second end, resistance R115 the second end are grounded.
Impedance inverter circuit solves to match between signals transmission middle impedance, and it reflects input circuit and output
Power transmission relation between circuit will obtain maximum power transmission, impedance matching is common when circuit realiration impedance matching
Between amplifying circuits at different levels, between amplifier and load, between measuring instrument and circuit-under-test, antenna and receiver or transmit
Between machine and antenna, etc..Need to accomplish impedance matching between the output circuit and buffer module of above-mentioned low-pass filtering module, no
During matching, the power output of low-pass filtering module can not all deliver to buffer module, if the impedance of buffer module is much smaller than
The output impedance of low-pass filtering module, low-pass filtering module are at overload, and its final power amplifier tube is easy to damage.
, whereas if the impedance of buffer module is excessive higher than the output impedance of low-pass filtering module, output voltage can be caused to raise, equally
It is unfavorable for the work of low-pass filtering module, sound can also produce distortion the therefore output impedance of low-pass filtering module and buffering mould
The impedance of block is closer to better.
Fig. 7 shows the circuit structure of the first buffer circuit, for convenience of description, illustrate only and implements with the utility model
The related part of example, details are as follows：
First buffer circuit 301 includes：Resistance R13, resistance R14, resistance R15, resistance R22, adjustable resistance VR1, field effect
Should pipe Q2, FET Q3, electric capacity C112, electric capacity C132.
The output end of first impedance inverter circuit 201 is connected with resistance R13 first end, FET Q2 grid G,
FET Q2 drain D is connected to first voltage source+12V with electric capacity C112 first end, and FET Q2 source S passes through
Adjustable resistance VR1 is connected with FET Q3 drain D, resistance R22 first end, resistance R22 the second end and resistance R15
First end, the first input end of audio signal amplification module 40 is connected；FET Q3 source S by resistance R14 with
FET Q3 grid G, electric capacity C132 first end, the second voltage source -12V are connected, resistance R13 the second end, electric capacity
C112 the second end, resistance R15 the second end, electric capacity C132 the second end are grounded.
Fig. 8 shows the circuit structure of the second buffer circuit, for convenience of description, illustrate only and implements with the utility model
The related part of example, details are as follows：
Second buffer circuit 302 includes：Resistance R45, resistance R63, resistance R57, resistance R58, adjustable resistance VR2, field effect
Should pipe Q4, FET Q5, electric capacity C134, electric capacity C150.
The output end of second impedance inverter circuit 202 is connected with resistance R63 first end, FET Q4 grid G,
FET Q4 drain D is connected to first voltage source+12V with electric capacity C134 first end, and FET Q4 source S passes through
Adjustable resistance VR2 is connected with FET Q5 drain D, resistance R58 first end, resistance R58 the second end and resistance R57
First end, the second input of audio signal amplification module 40 is connected；FET Q5 source S by resistance R45 with
FET Q5 grid G, electric capacity C150 first end, second source are connected, resistance R63 the second end, electric capacity C134
Second end, resistance R57 the second end, electric capacity C150 the second end are grounded.
First buffer circuit and the second buffer circuit, by FET Q2, FET Q3, FET Q4, field-effect
Pipe Q5 and peripheral component composition high current, High Linear Buffer output circuit, wherein FET Q2, FET Q3, field
Effect pipe Q4, FET Q5 be pairing audio low noise junction field effect transistor JFET, wherein, FET Q3 and
FET Q5 is 10mA constant current sources.With reference to whole buffer circuit output low noise, low distortion, Low ESR be low, high current
Audio signal.
Explanation is described to the operation principle of above-mentioned audio output circuit below in conjunction with Fig. 3 to Fig. 8：
First via simulated audio signal inputs the first low-pass filter circuit 101, by special low noise operational amplifier
The low-pass filter circuit of U26-B compositions, filters out other audio signals beyond predeterminated frequency value, by filtered analogue audio frequency
Signal output to the first impedance inverter circuit 201, filtered simulated audio signal forms slow via operational amplifier U25-B
Punching and impedance inverter circuit, the simulated audio signal after output impedance conversion is to the first mitigation circuits 301, the mould after impedance conversion
Intend audio signal and pass through the high current being made up of FET Q2 and FET Q3, High Linear Buffer output circuit, output is low
Noise, simulated audio signal to the audio signal of low distortion amplify electric module 40, low noise, the analogue audio frequency letter of low distortion
Number after the signal amplification circuit being made up of clear stereo Earphone Amplifier, output low noise, low distortion, left and right sound
The high audio signal of road separating degree.
Second road simulated audio signal inputs the first low-pass filter circuit 102, by special low noise operational amplifier
The low-pass filter circuit of U26-A compositions, filters out other audio signals beyond predeterminated frequency value, by filtered analogue audio frequency
Signal output to the first impedance inverter circuit 202, filtered simulated audio signal forms slow via operational amplifier U27-A
Punching and impedance inverter circuit, the simulated audio signal after output impedance conversion is to the first mitigation circuits 302, the mould after impedance conversion
Intend audio signal and pass through the high current being made up of FET Q4 and FET Q5, High Linear Buffer output circuit, output is low
Noise, simulated audio signal to the audio signal of low distortion amplify electric module 40, low noise, the analogue audio frequency letter of low distortion
Number after the signal amplification circuit being made up of clear stereo Earphone Amplifier, output low noise, low distortion, left and right sound
The high audio signal of road separating degree.
Fig. 9 shows the modular structure of audio decoding apparatus, for convenience of description, illustrate only and implements with the utility model
The related part of example, details are as follows：
Audio decoding apparatus includes：Usb audio demodulator 2, digital audio receiver 3, multiplexer 4, decoder 5 with
And the audio output circuit 1 that above-described embodiment provides；The first output end connection digital audio receiver 3 of usb audio demodulator 2
Input, usb audio demodulator 2 the second output end connection multiplexer 4 first input end, digital audio receiver
Second input of 3 output end connection multiplexer 4, the input of the output end connection decoder 5 of multiplexer 4,
First output end of decoder 5 connects the input of the first low-pass filter circuit 101, the second output end connection of decoder 5 the
The input of two low pass filters 102.
Usb audio demodulator 2 is used to pass through USB interface, receives Digital Audio Transmission, audio algorithm is realized using DSP storehouses
Processing.
Digital audio receiver 3 is used to receive multiple digital audio and video signals, and by the output of multiple digital audio and video signals at most
Path multiplexer 4.
Multiplexer 4 is used to be synthesized the multiple digital audio and video signals received, output individual digit audio letter
Number to decoder 5.
The decoder 5 is used to digital audio and video signals being converted into simulated audio signal, and by the simulated audio signal
Export to the first low-pass filter circuit 101 and the second low-pass filter circuit 102.
It is alternatively possible to audio signal is set via the first low-pass filter circuit 101, the first impedance inverter circuit 201,
After one buffer circuit 301 to audio signal amplification module 40, new audio signal is exported to headset left channel；Likewise, can be with
Audio signal is set via the second low-pass filter circuit 102, the second impedance inverter circuit 202, the second buffer circuit 302 to audio
After signal amplification module 40, new audio signal is exported to earphone R channel.
In the utility model embodiment, include low-pass filtering module, impedance change by being used in audio decoding apparatus
The audio output circuit of block, buffer module and audio signal output module is changed the mold, is exported by low-pass filtering module filtered
Audio signal is to impedance conversion module, and impedance conversion module enters row buffering to filtered audio signal and converted with impedance, output
Audio signal after conversion is to buffer module, and buffer module carries out buffered to the audio signal after conversion, after output buffers
Audio signal to audio signal amplification module, so as to output low noise, the audio signal of low distortion.
It is described above, only specific embodiment of the present utility model, but the scope of protection of the utility model is not limited to
In this, any one skilled in the art can readily occur in various in the technical scope that the utility model discloses
Equivalent modifications or substitutions, these modifications or substitutions should all cover within the scope of protection of the utility model.Therefore, this practicality
New protection domain should be defined by scope of the claims.
Claims (9)
1. a kind of audio output circuit of audio decoding apparatus, it is characterised in that the audio output circuit includes：LPF
Module, impedance conversion module, buffer module and audio signal amplification module, the output end connection institute of the low-pass filtering module
The input of impedance conversion module is stated, the output end of the impedance conversion module connects the input of the buffer module, described
The output end of buffer module connects the input of the audio signal amplification module；
The low-pass filtering module includes the first low-pass filter circuit and the second low-pass filter circuit, the first LPF electricity
Road is used to carry out the simulated audio signal received LPF, and the first audio that output frequency value is less than predeterminated frequency value is believed
Number；Second low-pass filter circuit is used to carry out LPF to the simulated audio signal received, and output frequency value is less than
Second audio signal of predeterminated frequency value；
The impedance conversion module includes the first impedance inverter circuit and the second impedance inverter circuit, the first impedance conversion electricity
The input on road connects the output end of first low-pass filter circuit, the input connection institute of second impedance inverter circuit
State the output end of the second low-pass filter circuit；
First impedance inverter circuit is used to carry out impedance conversion to first audio signal received, exports the 3rd sound
Frequency signal；Second impedance inverter circuit is used to carry out second audio signal that receives impedance conversion, output the
Four audio signals；
The buffer module includes the first buffer circuit and the second buffer circuit, the input connection institute of first buffer circuit
The output end of the first impedance inverter circuit is stated, the input of second buffer circuit connects second impedance inverter circuit
Output end；
First buffer circuit is used to carry out the 3rd audio signal received buffered, output fifth audio letter
Number；Second buffer circuit is used to carry out the 4th audio signal received buffered, output the 6th audio letter
Number；
The audio signal amplification module includes Earphone Amplifier integrated chip, the output end connection institute of first buffer circuit
The first pin of Earphone Amplifier integrated chip is stated, the output end of second buffer circuit connects the Earphone Amplifier and integrated
The second pin of chip, the audio signal amplification module are used to believe the fifth audio signal received and the 6th audio
Number fidelity enhanced processing is carried out, and export final audio signal respectively.
2. audio output circuit as claimed in claim 1, it is characterised in that the audio output circuit also includes interface mould
Block；
The output end of first low-pass filter circuit connects the first input end of the interface module, second LPF
The output end of circuit connects the second input of the interface module, the first output end connection described first of the interface module
The input of impedance inverter circuit, the second output end of the interface module connect the input of second impedance inverter circuit
End.
3. audio output circuit as claimed in claim 2, it is characterised in that first low-pass filter circuit includes：Resistance
R59, resistance R60, resistance R61, resistance R64, resistance R72, resistance R73, resistance R77, electric capacity C114, electric capacity C115, electric capacity
C116, electric capacity C121, electric capacity C128, electric capacity C129, low noise operational amplifier U26-B, first voltage source, the second voltage source；
The first end of the resistance R60 and the first end, the first end of the resistance R61, the electric capacity C116 of the resistance R59
First end be connected, the second end of the resistance R61 and the electric capacity C114 first end, the low noise operational amplifier
U26-B positive input terminal is connected, the positive power source terminal of the low noise operational amplifier U26-B and the first of the electric capacity C115
End is connected to the first voltage source；The first end of the resistance R72 and resistance R73 first end, the resistance R77
First end, the first end of the electric capacity C121 are connected, the second end of the resistance R73 and the electric capacity C128 first end,
The negative input end of the low noise operational amplifier U26-B is connected, the negative supply of the low noise operational amplifier U26-B
End and the first end of the electric capacity C128 are connected to the second voltage source；The second end of the resistance R77 and the electric capacity
C128 the second end, the first end of the resistance R64, the output end of the low noise operational amplifier U26-B are connected, described
Resistance R64 the second end connects the first input end of the interface module；The second end of the resistance R59, the electric capacity C114
The second end, the second end of the electric capacity C115, the second end of the electric capacity C116, the second end, described of the electric capacity C121
Electric capacity C129 the second end is grounded.
4. audio output circuit as claimed in claim 2, it is characterised in that second low-pass filter circuit includes：Resistance
R86, resistance R87, resistance R88, resistance R91, resistance R96, resistance R97, resistance R100, electric capacity C136, electric capacity C137, electric capacity
C139, electric capacity C145, low noise operational amplifier U26-A；
The first end of the resistance R87 and the first end, the first end of the resistance R88, the electric capacity C137 of the resistance R86
First end be connected, the second end of the resistance R88 and the electric capacity C136 first end, the low noise operational amplifier
U26-A positive input terminal is connected；The first end of the resistance R96 and electric capacity C139 first end, the resistance R97
First end, the first end of the resistance R100 are connected, the second end of the resistance R97 and the electric capacity C145 first end,
The negative input end of the low noise operational amplifier U26-A is connected；The second end of the resistance R100 and the electric capacity C145
The second end, first end, the output end of the low noise operational amplifier U26-A of the resistance R91 be connected, the resistance
R91 the second end connects the second input of the interface module；The second end of the resistance R86, the of the electric capacity C136
Two ends, the second end of the electric capacity C137, the second end of the electric capacity C139 are grounded.
5. audio output circuit as claimed in claim 3, it is characterised in that first impedance inverter circuit includes：Resistance
R65, resistance R66, resistance R80, resistance R106, resistance R108, electric capacity C131, electric capacity C133, electric capacity C148, electric capacity C113, fortune
Put U25-B；
First output end of the interface module connects the first end of the resistance R106, the second end of the resistance R106 and institute
The first end, the first end of the resistance R108, the positive input terminal of the amplifier U25-B for stating electric capacity C148 are connected, the fortune
The first end of the positive power source terminal and the electric capacity C113 of putting U25-B is connected to the first voltage source；The first of the resistance R65
The negative input end with the first end of the electric capacity C131, the first end of the resistance R80, the amplifier U25-B is held to be connected, institute
The first end of the negative power end and the electric capacity C133 of stating amplifier U25-B is connected to the second voltage source；The electric capacity C131
The second end be connected described by the resistance R66 with the second end of the resistance R80, the output end of the amplifier U25-B
The input of one buffer circuit, the second end of the resistance R65, the second end of the electric capacity C148, the of the resistance R108
Two ends, the second end of the electric capacity C133, the second end of the electric capacity C113 are grounded.
6. audio output circuit as claimed in claim 2, it is characterised in that second impedance inverter circuit includes：Resistance
R92, resistance R107, resistance R109, resistance R115, resistance R62, electric capacity C149, electric capacity C157, amplifier U27-A；
Second output end of the interface module connects the first end of the resistance R109, the second end of the resistance R109 and institute
The first end, the first end of the resistance R115, the positive input terminal of the amplifier U27-A for stating electric capacity C157 are connected；The electricity
Hinder R92 first end and the first end of the electric capacity C149, the first end of the resistance R107, the amplifier U27-A it is negative defeated
Enter end to be connected；The second end of the electric capacity C149 leads to the second end of the resistance R107, the output end of the amplifier U27-A
Cross the input that the resistance R62 is connected to second buffer circuit, the second end of the resistance R92, the electric capacity C157
The second end, the second end of the resistance R115 is grounded.
7. audio output circuit as claimed in claim 3, it is characterised in that first buffer circuit includes：Resistance R13,
Resistance R14, resistance R15, resistance R22, adjustable resistance VR1, FET Q2, FET Q3, electric capacity C112, electric capacity C132；
The output end of first impedance inverter circuit and the first end of the resistance R13, the grid phase of the FET Q2
Connection, the drain electrode of the FET Q2 and the first end of the electric capacity C112 are connected to the first voltage source, the field effect
Should pipe Q2 source electrode by the draining of the adjustable resistance VR1 and the FET Q3, the first end of the resistance R22 is connected
Connect, the second end of the resistance R22 and the resistance R15 first end, the first input end of the audio signal amplification module
It is connected；Grid, the electric capacity C132 that the source electrode of the FET Q3 passes through the resistance R14 and FET Q3
First end, the second voltage source be connected, the second end of the resistance R13, the second end of the electric capacity C112, the electricity
Resistance R15 the second end, the second end of the electric capacity C132 is grounded.
8. audio output circuit as claimed in claim 3, it is characterised in that second buffer circuit includes：Resistance R45,
Resistance R63, resistance R57, resistance R58, adjustable resistance VR2, FET Q4, FET Q5, electric capacity C134, electric capacity C150；
The output end of second impedance inverter circuit and the first end of the resistance R63, the grid phase of the FET Q4
Connection, the drain electrode of the FET Q4 and the first end of the electric capacity C134 are connected to the first voltage source, the field effect
Should pipe Q4 source electrode by the draining of the adjustable resistance VR2 and the FET Q5, the first end of the resistance R58 is connected
Connect, the second end of the resistance R58 and the resistance R57 first end, the second input of the audio signal amplification module
It is connected；Grid, the electric capacity C150 that the source electrode of the FET Q5 passes through the resistance R45 and FET Q5
First end, the second source be connected, the second end of the resistance R63, the second end of the electric capacity C134, the resistance
R57 the second end, the second end of the electric capacity C150 are grounded.
9. a kind of audio decoding apparatus, it is characterised in that the audio decoding apparatus includes：Usb audio demodulator, digital sound
Audio output circuit described in frequency receiver, multiplexer, decoder and any one of claim 1 to 8；The USB sounds
First output end of frequency demodulator connects the input of the digital audio receiver, and the second of the usb audio demodulator is defeated
Go out the first input end that end connects the multiplexer, the output end of the digital audio receiver connects the multiplexing
Second input of device, the input of the output end connection decoder of the multiplexer, the first of the decoder
Output end connects the input of first low-pass filter circuit, and the second output end of the decoder connects second low pass
The input of wave filter；
The usb audio demodulator is used to pass through USB interface, receives Digital Audio Transmission, is realized using DSP storehouses at audio algorithm
Reason；
The digital audio receiver is used to receive multiple digital audio and video signals, and by the multiple digital audio and video signals export to
The multiplexer；
The multiplexer is used to be synthesized the multiple digital audio and video signals received, exports individual digit audio
Signal is to the decoder；
The decoder is used to digital audio and video signals being converted into simulated audio signal, and by the simulated audio signal export to
First low-pass filter circuit and the second low-pass filter circuit.
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| CN201720339321.3U CN206894870U (en) | 2017-03-31 | 2017-03-31 | Audio decoding apparatus and its audio output circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106851483A (en) * | 2017-03-31 | 2017-06-13 | 先歌国际影音有限公司 | Audio decoding apparatus and its audio output circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106851483A (en) * | 2017-03-31 | 2017-06-13 | 先歌国际影音有限公司 | Audio decoding apparatus and its audio output circuit |
| CN106851483B (en) * | 2017-03-31 | 2022-08-12 | 先歌国际影音股份有限公司 | Audio decoding device and audio output circuit thereof |
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Address after: 518000 1st floor, electronic building, Jiuwei Xiange technology and Culture Industrial Park, Jiuwei community, Hangcheng street, Bao'an District, Shenzhen, Guangdong Province Patentee after: IAG Group Ltd. Address before: 518000 Jiuwei Xiange science and Technology Industrial Park, Xi Township, Bao'an District, Shenzhen City, Guangdong Province Patentee before: IAG GROUP Co.,Ltd. |
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