CN2783658Y - High fidelity audio output device for digital video receiving set-top box - Google Patents
High fidelity audio output device for digital video receiving set-top box Download PDFInfo
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- CN2783658Y CN2783658Y CNU2005200542228U CN200520054222U CN2783658Y CN 2783658 Y CN2783658 Y CN 2783658Y CN U2005200542228 U CNU2005200542228 U CN U2005200542228U CN 200520054222 U CN200520054222 U CN 200520054222U CN 2783658 Y CN2783658 Y CN 2783658Y
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- operational amplifier
- top box
- circuit
- output device
- digital video
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Abstract
The utility model relates to a high-fidelity audio output device for a top box of a digital video receiving machine, which comprises a digital-analog converter, a denoising circuit, an operational amplifier, a denoising shock-absorbing circuit and an output buffer denoising circuit, wherein an output terminal of the digital-analog converter is connected with an input terminal of the operational amplifier; an output terminal of the operational amplifier is connected with an input terminal of the output buffer denoising circuit which is arranged at the input terminal of the operational amplifier; the denoising shock-absorbing circuit is connected between the input terminal and the output terminal of the operational amplifier, wherein the operational amplifier adopts the 5532 operational amplification, and the denoising circuit and the denoising shock-absorbing circuit are respectively formed by capacitors. Adopting the acoustic frequency output device, the audio noise is reduced, and the interference of a right acoustic channel and a left acoustic channel are reduced; thereby, the audio quality is improved, and the audio-visual demand of a user is satisfied. In addition, the utility model has the advantages of simple circuit, low cost and high price ratio.
Description
Technical field
The utility model relates to a kind of audio output device of digital video receiver set-top box.
Background technology
Digital Television had entered from the experimental stage in China over the past two years and had developed the popularization stage, and the digital video receiver top box is an indispensable key equipment in the Digital Television evolution.Because Audio Processing is not the key technology of digital TV set-top box, so adopt cheap amplifiers such as 4558 or LM358 to be used as designing device usually at the preposition amplifier section of audio frequency.While also goes up too simple in line design, consequently set-top box audio frequency output performance is very poor.Can see the problem of existence from several index contrasts of national standard and the actual measurement of former set-top box.
| Sequence number | Test item | Unit | Specification requirement (national standard) | Examine then result | Remarks |
| 1 | Audio output level | dbu | -3＜～＜+6 | -1.76 | Qualified |
| 2 | Total harmonic distortion | ％ | ＜＝1.5(60hz-18khz) | 0.83 | Qualified |
| 3 | The audio frequency amplitude-frequency characteristic | db | +1/-2(60hz-18hz) | 0.77 | Qualified |
| 4 | Audio frequency signal to noise ratio (not weighting) | db | ＞＝70 | 68 | Defective |
| 5 | The audio frequency interchannel crosstalk | db | ＜＝-70 | -46 | Defective |
Test result can be seen from table: audio frequency signal to noise ratio, audio frequency interchannel crosstalk, binomial index are defective, though it is too small and can not satisfy the demands that the qualified but user of audio output level item index generally reacts volume in addition, if volume can be met total harmonic distortion liter is caused 13.5% and cause the serious distortion of audio frequency when output level is transferred to 5～6db.
The utility model content
Problem to be solved in the utility model is the noise of reduction digital video receiver top box audio output device and crosstalks.
Be head it off, the utility model provides a kind of digital video receiver top box HD Audio output device, comprises digital to analog converter DAC, operational amplifier, output buffering Dolby circuit; The output of described digital to analog converter links to each other with the input of operational amplifier, and the output of operational amplifier links to each other with the input of output buffering Dolby circuit; The input of operational amplifier also is provided with Dolby circuit.
As improvement, also be provided with noise reduction weakening circuit between the output of the operational amplifier of the utility model digital video receiver top box HD Audio output device and the input.
As selection, the output of the digital to analog converter DAC of the utility model digital video receiver top box HD Audio output device links to each other with the input of operational amplifier with capacitance C64, C50 by current-limiting resistance R55, R66, and described Dolby circuit is made of the tie point that is connected current-limiting resistance R55, R66 and capacitance C64, C50 and noise reduction capacitor C 148, C91 between the ground.
Select as another, the noise reduction weakening circuit of the utility model digital video receiver top box HD Audio output device is made of the building-out capacitor between inversion signal input that is connected in parallel on operational amplifier and the output (C150, C92).
As another selection, the operational amplifier of the utility model digital video receiver top box HD Audio output device is that model is 5532 dual operational amplifier integrated circuit.
As further selection, the capacitance of the noise reduction electric capacity (C148, C91) of the utility model digital video receiver top box HD Audio output device is 100PF～470PF.
As further selecting the capacitance 33PF～150PF of the building-out capacitor (C150, C92) of the utility model digital video receiver top box HD Audio output device.
Adopt the utility model digital video receiver top box HD Audio output device, static (volume is opened maximum) do not have obvious residual noise, clear, transparent, the no burr sense of high pitch in the time of dynamically.Bass is full, high resilience and do not have muddy sense, has satisfied user's audiovisual demand.In addition, because circuit is simple, with low cost, thereby have than high performance-price ratio.
Below in conjunction with accompanying drawing, the utility model digital video receiver top box HD Audio output device is described further by embodiment.
Description of drawings
Figure 1 shows that the structured flowchart of the utility model digital video receiver top box HD Audio output device;
Figure 2 shows that the electrical schematic diagram of the utility model digital video receiver top box HD Audio output device.
Embodiment
As shown in Figure 1, digital audio and video signals process digital-to-analogue conversion from microprocessor MCU, export respectively from the left and right sound track signals output of digital to analog converter (DAC), wherein: the right wing signal outputs to the next stage amplifying circuit by the first Dolby circuit R1, first operational amplifier, the first output buffering Dolby circuit R3, and the input of first operational amplifier and output are parallel with the first noise reduction weakening circuit R2; Left side road signal outputs to the next stage amplifying circuit by the second Dolby circuit L1, second operational amplifier, the second output buffering Dolby circuit L3, and the input of second operational amplifier and output are parallel with the second noise reduction weakening circuit L2.
Electrical schematic diagram as shown in Figure 2, the R channel output of digital to analog converter links to each other with the in-phase signal input of first operational amplifier by current-limiting resistance R66, capacitance C50, and the first Dolby circuit R1 is made of tie point that is connected current-limiting resistance R66 and capacitance C50 and the noise reduction capacitor C 91 between the ground; The L channel output of digital to analog converter links to each other with the in-phase signal input of second operational amplifier by current-limiting resistance R55, capacitance C64, and the second Dolby circuit L1 is made of tie point that is connected current-limiting resistance R55 and capacitance C64 and the noise reduction capacitor C 148 between the ground.The first noise reduction weakening circuit R2 is made of the building-out capacitor C92 between inversion signal input that is connected in parallel on first operational amplifier and the output; The second weakening circuit L2 that makes an uproar calculates the inversion signal input of amplifier and the building-out capacitor C150 between the output constitutes by being connected in parallel on second.Other is same as the prior art.
Because the DAC circuit does not have digital filtering not have the LPF circuit yet, this reason causes the residual tonequality that too much had a strong impact on of quantizing noise just.A kind of special construction that building-out capacitor (C150 or C92) can form a low pass filter is set, it can make quantize high frequency noise (ear-piercing electronics sound) frequency response cut down to-below the 85dB.R64 in the circuit and C150 (or R65 and C92) component frequency compensating network can be carried out phase compensation to the high frequency feedback signal, to improve the stability of IC.It can suppress high-frequency resonant forcefully under big signal operating state, further reduced noise.The size of building-out capacitor C150, C92 should be matched according to the size of gain (GAIN=1+R64/R67).Building-out capacitor C150, C92 are too little, and signal to noise ratio (S/N) be cannot get through (low excessively), and too big frequency response meeting worsens.General indemnity capacitor C150, C92 can select (break frequency FOL=1/ (2 ∏ R64C150), FOR=1/ (2 ∏ R65C92)) in 33PF～150PF scope.
In addition, the capacity of noise reduction capacitor C91, C148 can be selected for use in 100PF～470P scope.
In concrete enforcement, it is 5532 dual operational amplifier integrated circuit that operational amplifier in the utility model digital video receiver top box HD Audio output device can be selected model for use, amplifier emperor NE5532 for example, it have good and cheap, at a high speed, low noise characteristics.
Adopt the utility model digital video receiver top box HD Audio output device, first order Dolby circuit R1, L1 make the circuit white noise descend nearly about 40%, noise further reduces after second level noise reduction+weakening circuit R2, L2 handles, the self-excitation that is easy to generate in large-signal has simultaneously also obtained inhibition, add 5532 superior functions own, the audio frequency output quality greatly improves.When output level reach+(max volume) its total harmonic distortion is less than 0.0022% during 6db, audio frequency signal to noise ratio (not weighting) reaches 80.8db, sound is crosstalked and is reached-83.5db about audio frequency, the audio frequency amplitude-frequency characteristic has been dropped to-0.2db by original 0.77db, detects the performance requirement that index has reached the preposition amplification output of high-fidelity (Hi-Fi) audio frequency.
Claims (9)
1. a digital video receiver top box HD Audio output device comprises digital to analog converter (DAC), operational amplifier, output buffering Dolby circuit; The output of described digital to analog converter (DAC) links to each other with the input of operational amplifier, and the output of operational amplifier links to each other with the input of output buffering Dolby circuit; The input of operational amplifier also is provided with Dolby circuit (R1, L1).
2. digital video receiver top box HD Audio output device according to claim 1 is characterized in that: also be provided with noise reduction weakening circuit (R2, L2) between the output of operational amplifier and the input.
3. digital video receiver top box HD Audio output device according to claim 1, it is characterized in that: the output of described digital to analog converter (DAC) links to each other with the input of operational amplifier with capacitance (C64, C50) by current-limiting resistance (R55, R66), and described Dolby circuit is made of tie point that is connected current-limiting resistance (R55, R66) and capacitance (C64, C50) and the noise reduction electric capacity between the ground (C148, C91).
4. as digital video receiver top box HD Audio output device as described in the claim 2, it is characterized in that: the output of described digital to analog converter (DAC) links to each other with the input of operational amplifier with capacitance (C64, C50) by current-limiting resistance (R55, R66), and described Dolby circuit is made of tie point that is connected current-limiting resistance (R55, R66) and capacitance (C64, C50) and the noise reduction electric capacity between the ground (C148, C91).
5. as digital video receiver top box HD Audio output device as described in claim 2 or 4, it is characterized in that: noise reduction weakening circuit is made of the building-out capacitor between inversion signal input that is connected in parallel on operational amplifier and the output (C150, C92).
6. as digital video receiver top box HD Audio output device as described in each in the claim 1 to 4, it is characterized in that: operational amplifier is that model is 5532 dual operational amplifier integrated circuit.
7. as digital video receiver top box HD Audio output device as described in the claim 5, it is characterized in that: operational amplifier is that model is 5532 dual operational amplifier integrated circuit.
8. as digital video receiver top box HD Audio output device as described in claim 3 or 4, it is characterized in that: the capacitance of described noise reduction electric capacity (C148, C91) is 100PF～470PF.
9. as digital video receiver top box HD Audio output device as described in the claim 5, it is characterized in that: the capacitance 33PF～150PF of described building-out capacitor (C150, C92).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2005200542228U CN2783658Y (en) | 2005-01-21 | 2005-01-21 | High fidelity audio output device for digital video receiving set-top box |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2005200542228U CN2783658Y (en) | 2005-01-21 | 2005-01-21 | High fidelity audio output device for digital video receiving set-top box |
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| Publication Number | Publication Date |
|---|---|
| CN2783658Y true CN2783658Y (en) | 2006-05-24 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2005200542228U Expired - Lifetime CN2783658Y (en) | 2005-01-21 | 2005-01-21 | High fidelity audio output device for digital video receiving set-top box |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101483437B (en) * | 2009-01-19 | 2011-03-16 | 中国北车股份有限公司大连电力牵引研发中心 | Low cost, high precision 16 bit A/D converter based on FPGA |
| CN103167381A (en) * | 2011-12-16 | 2013-06-19 | 三星电子株式会社 | Terminal having a plurality of speakers and method of operating the same |
| CN106653038A (en) * | 2016-09-09 | 2017-05-10 | 深圳来邦科技有限公司 | Sound amplifying system |
| CN114051127A (en) * | 2022-01-14 | 2022-02-15 | 深圳市艾科维达科技有限公司 | Image transmission noise reduction method of network set top box |
-
2005
- 2005-01-21 CN CNU2005200542228U patent/CN2783658Y/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101483437B (en) * | 2009-01-19 | 2011-03-16 | 中国北车股份有限公司大连电力牵引研发中心 | Low cost, high precision 16 bit A/D converter based on FPGA |
| CN103167381A (en) * | 2011-12-16 | 2013-06-19 | 三星电子株式会社 | Terminal having a plurality of speakers and method of operating the same |
| CN106653038A (en) * | 2016-09-09 | 2017-05-10 | 深圳来邦科技有限公司 | Sound amplifying system |
| CN114051127A (en) * | 2022-01-14 | 2022-02-15 | 深圳市艾科维达科技有限公司 | Image transmission noise reduction method of network set top box |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| ASS | Succession or assignment of patent right |
Owner name: MSTAR SOFTWARE DEVELOPMENT INC. Free format text: FORMER OWNER: BIQOQI DIGITAL CODE TECH CO., LTD., SHENZHEN CITY Effective date: 20130731 |
|
| C41 | Transfer of patent application or patent right or utility model | ||
| COR | Change of bibliographic data |
Free format text: CORRECT: ADDRESS; FROM: 518051 SHENZHEN, GUANGDONG PROVINCE TO: 518057 SHENZHEN, GUANGDONG PROVINCE |
|
| TR01 | Transfer of patent right |
Effective date of registration: 20130731 Address after: 518057 Guangdong city of Shenzhen province Nanshan District Gao Xin Road China science and Technology Development Institute of Technology Park building three floor tower 4-5 Patentee after: MStar Software Development (Shenzhen) Co., Ltd. Address before: 711 hatch room 518051, China Science and Technology Development Institute, hi tech Industrial Park, Guangdong, Shenzhen Patentee before: Shenzhen Bianqi Digital Technologies Co., Ltd. |
|
| C17 | Cessation of patent right | ||
| CX01 | Expiry of patent term |
Expiration termination date: 20150121 Granted publication date: 20060524 |