CN102263557A - Delta modulation type converter and method for eliminating crackle noise thereof - Google Patents
Delta modulation type converter and method for eliminating crackle noise thereof Download PDFInfo
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- CN102263557A CN102263557A CN2010101904734A CN201010190473A CN102263557A CN 102263557 A CN102263557 A CN 102263557A CN 2010101904734 A CN2010101904734 A CN 2010101904734A CN 201010190473 A CN201010190473 A CN 201010190473A CN 102263557 A CN102263557 A CN 102263557A
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- 208000037656 Respiratory Sounds Diseases 0.000 title abstract 3
- 238000012545 processing Methods 0.000 claims abstract description 4
- 238000005336 cracking Methods 0.000 claims description 17
- 238000005070 sampling Methods 0.000 claims description 9
- 240000000233 Melia azedarach Species 0.000 claims description 2
- 230000002238 attenuated effect Effects 0.000 abstract 3
- 230000008030 elimination Effects 0.000 description 2
- 238000003379 elimination reaction Methods 0.000 description 2
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- 238000013139 quantization Methods 0.000 description 2
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Abstract
The invention is applied to the field of multimedia terminals and provides a delta modulation type converter and a method for eliminating the crackle noise of the delta modulation type converter. The method comprises the following steps: carrying out attenuation processing on a signal of audio data which is sampled before switching when a command of switching audio data is received; and executing the switching of the audio data when the signal is attenuated to a target value. In the invention, in the middle of the switching of the audio data, the signal outputted by a digital circuit part to an analog circuit part is attenuated, and the audio data can be switched when the signal is attenuated to the target value, thus the crackle noise caused by a larger difference between output levels before and after switching can be avoided.
Description
Technical field
The invention belongs to the field, multimedia terminal, relate in particular to a kind of delta modulation type transducer and eliminate the method for its cracking noise.
Background technology
Use modulation incremental transducer playing back music, produce cracking noise (pop noise) sometimes, acoustically impacting to the audience, cracking noise mainly concentrates on following three phases:
1, (Digital-to-Analog Converter when DAC) not starting as yet, may remainingly have certain electric charge on the equivalent capacity on the earphone cord to transducer.Output level when these remaining electric charges can just start DAC exerts an influence, if the voltage of remaining electric charge is higher, will produce crack noise.
When 2, in the playing back music process, switching suddenly, the output level of DAC is V1 before supposing to switch, and the song after switching to require the output level of DAC when just having begun to play be V2, if bigger difference is arranged between V1 and the V2, also can produce apparent in view cracking noise.
When 3, DAC closed, the output level of DAC may be V3 before supposing to close, if close the driving tube of DAC at once, output voltage is changed to 0 suddenly from V3, also can produce tangible cracking noise.
Summary of the invention
The method that the purpose of the embodiment of the invention is to provide a kind of delta modulation type transducer and eliminates its cracking noise is intended to eliminate the cracking noise of delta modulation type transducer.
The embodiment of the invention is achieved in that a kind of method of eliminating delta modulation type transducer cracking noise, may further comprise the steps:
When receiving the order of switch audio data, the signal of the voice data before the switching that sampling is obtained carries out attenuation processing;
After decaying to desired value, carry out the switching of voice data.
The delta modulation type transducer that the embodiment of the invention provides comprises digital circuit unit and the analog circuit unit that is connected, and described digital circuit unit comprises: the interpolation filter of Lian Jieing, sigma-delta modulator, Dynamic matching unit successively; Described sigma-delta modulator is used for when receiving the order of switch audio data, and the signal of the voice data before the switching that the sampling of described interpolation filter is obtained decays to desired value.
The embodiment of the invention also provides a kind of multimedia play terminal, and it comprises as mentioned above a delta modulation type transducer.
In the embodiment of the invention, in the middle of voice data switches, the signal that digital circuit is partly exported to artificial circuit part is decayed, and just switches after decaying to desired value, thereby has avoided owing to the big cracking noise that causes of output level difference before and after switching.
Description of drawings
Fig. 1 is the architecture principle figure of the multimedia play terminal that provides of the embodiment of the invention;
Fig. 2 is the structure principle chart of digital circuit unit among Fig. 1;
Fig. 3 is the realization flow figure of the method for the elimination delta modulation type transducer cracking noise that provides of the embodiment of the invention.
Embodiment
In order to make purpose of the present invention, technical scheme and advantage clearer,, the present invention is further elaborated below in conjunction with drawings and Examples.Should be appreciated that specific embodiment described herein only in order to explanation the present invention, and be not used in qualification the present invention.
In the embodiment of the invention, in the middle of voice data switched, the signal that digital circuit is partly exported to artificial circuit part was decayed, and just switches after decaying to desired value.
Fig. 1 shows the architecture principle of the multimedia play terminal that the embodiment of the invention provides, and for convenience of description, only shows the part relevant with present embodiment.
With reference to Fig. 1, a built-in delta modulation type transducer 11 is as audio-frequency unit in the multimedia play terminal 1, and wherein delta modulation type transducer 11 includes digital circuit unit 111 and the analog circuit unit 112 that is connected.Wherein analog circuit unit 112 is as the output of delta modulation type converter 11, and when earphone inserted, analog circuit unit 112 was connected with earphone cord.
Fig. 2 shows the structural principle of digital circuit unit 111 among Fig. 1, interpolation filter 1111, sigma-delta modulator 1112, Dynamic matching unit 1113 connects successively, wherein interpolation filter 1111 is by first order half-band filter, second level half-band filter and comb filter constitute, after interpolation filter 1111 samplings of the voice data process of input, be input to after sigma-delta modulator 1112 modulates, be input to Dynamic matching unit 1113 then, produce the pseudorandom quantization signal by Dynamic matching unit 1113, quantized data after sigma-delta modulator 1112 modulation is carried out " upset ", reduce the nonlinearity erron that multi bit quantization brings.
In the embodiment of the invention, for eliminate the noise that delta modulation type transducer 11 produces owing to the switching music in the playing back music process, sigma-delta modulator 1112 is set especially when receiving the order of switch audio data, the signal of the voice data before the switching that interpolation filter 1111 sampling is obtained decays to a desired value (as 0V), can realize that specifically the signal of the voice data before the switching that these state machine control interpolation filter 1111 samplings obtain is decremented to desired value step by step by a built-in state machine in sigma-delta modulator 1112.
For example, sigma-delta modulator 1112 has two-way output to be respectively high signal a[3:0] and low level signal b[4:0], this two-way output is delivered to Dynamic matching unit 1113 and is carried out " upset ".As high signal a[3:0]==4 ' b0100﹠amp; ﹠amp; B[4:0]=during=5 ' b01000, the output level of representative simulation circuit unit 112 is 0.Detailed process is:
When a. switching music, software sends the function that a control signal fade_out_en enables to decay earlier;
B. after digital circuit unit 111 detects the fade_out_en signal, latch the output high signal a[3:0 of current sigma-delta modulator 1112] and low level signal b[4:0];
C. allow high signal a[3:0] slowly become 4 ' b0100, allow low level signal b[4:0 then] slowly become 5 ' b01000; Allow a[3:0] and b[4:0] decay to 0 in how long, the register fade_fator[3:0 that is used for controlling the rate of decay that can dispose by software] control, suppose fadefator[3:0] value be configured to k, a[3:0 so] allow a[3:0 in the cycle at 2^k delta modulation type transducer work clock] decay to 0, b[4:0] allow b[4:0 in the cycle at the work clock of the individual delta modulation type of 2^ (k+2) transducer] decay to 0.This register maximum of fade_fator is 15, has guaranteed can decay to 0 in 500 milliseconds when the full amplitude of ∑-Δ DAC is exported;
D. work as a[3:0]==4 ' b0100﹠amp; ﹠amp; B[4:0]=during=5 ' b01000, ∑-Δ DAC has decayed to 0, and at this moment the digital circuit of DAC produces the state that decay is finished, and is stored in the status register, and software is read this state, just can begin to have play an other first song.
Further, cracking noise when starting in order to reduce delta modulation type transducer 11, output at analogue unit 112 is provided with first switching tube, this first switching tube, one end ground connection, when delta modulation type transducer 11 is activated, the equivalent capacity of this first switching tube and earphone cord forms parallel-connection structure, and the remaining electric charge of the equivalent capacity of earphone cord can discharge along switching tube.Described first switching tube can adopt the COMS pipe to realize, the source electrode of COMS pipe and drain electrode are connected to the two ends of the equivalent capacity of earphone cord, and when delta modulation type transducer 11 was activated, the grid of COMS pipe was unlocked.
In like manner, when closing delta modulation type transducer 11, the mode that one second switch pipe can be set equally and connect discharges the equivalent output capacitance and the remaining electric charge of the equivalent capacity on the earphone cord of delta modulation type transducer 11, second switch pipe one end ground connection wherein, form parallel-connection structure with the equivalent capacity of earphone cord and the equivalent output capacitance of delta modulation type transducer 11, can adopt the COMS pipe to realize equally, source electrode and drain electrode are connected to the two ends of the equivalent output capacitance of the equivalent capacity of earphone cord and delta modulation type transducer 11, when delta modulation type transducer 11 was closed, the grid of COMS pipe was unlocked.
The cracking noise that produces during for opening and closing delta modulation type transducer 11, many the paths that discharge the electric charge of equivalent capacity on the earphone cord and delta modulation type transducer 11 equivalent output capacitances are provided respectively, again according to actual conditions, such as different earphone cords, different chip production technology, different applicable cases, selecting wherein, the path of an optimum discharges remaining electric charge, such as for opening path, 60 microamperes, 120 microamperes, 180 microamperes path can be set, therefrom select a path to use by test when manufacturing.Close access also is so, repeats no more.
Fig. 3 shows the realization flow of the method for the elimination delta modulation type transducer cracking noise that the embodiment of the invention provides, and details are as follows:
In step S301, when starting delta modulation type transducer, control the first switching tube closure in parallel, first switching tube, one end ground connection with the equivalent capacity of earphone cord.
In step S302, when receiving the order of switch audio data, the signal of the voice data before the switching that sampling is obtained carries out attenuation processing; After decaying to desired value, carry out the switching of voice data.
In step S303, when closing delta modulation type transducer, control and the equivalent capacity of earphone cord and the equivalent output capacitance second switch pipe closure in parallel of described delta modulation type transducer, described second switch pipe one end ground connection.
Above-mentioned three steps correspond respectively to the situation of opening delta modulation type transducer, delta modulation type transducer switching music, closing delta modulation type transducer, can adopt above-mentioned arbitrary step separately during concrete enforcement, also can adopt wherein any two or all.
In the embodiment of the invention, in the middle of voice data switches, the signal that digital circuit is partly exported to artificial circuit part is decayed, after decaying to desired value, just switch, thereby avoided owing to the big cracking noise that causes of output level difference before and after switching, this method can be by software control, and the speed-controllable system of decay is very flexible.And the cracking noise that produces when opening and closing delta modulation type transducer then can be controlled the path of the release current of connection and eliminate noise.
The above only is preferred embodiment of the present invention, not in order to restriction the present invention, all any modifications of being done within the spirit and principles in the present invention, is equal to and replaces and improvement etc., all should be included within protection scope of the present invention.
Claims (10)
1. a method of eliminating delta modulation type transducer cracking noise is characterized in that, may further comprise the steps:
When receiving the order of switch audio data, the signal of the voice data before the switching that sampling is obtained carries out attenuation processing;
After decaying to desired value, carry out the switching of voice data.
2. the method for claim 1 is characterized in that, described method is further comprising the steps of:
When starting delta modulation type transducer, control the first switching tube closure in parallel, described first switching tube, one end ground connection with the equivalent capacity of earphone cord.
3. method as claimed in claim 1 or 2, it is characterized in that, described method is further comprising the steps of: when closing delta modulation type transducer, control and the equivalent capacity of earphone cord and the equivalent output capacitance second switch pipe closure in parallel of described delta modulation type transducer, described second switch pipe one end ground connection.
4. a delta modulation type transducer comprises the digital circuit unit and the analog circuit unit that are connected, it is characterized in that described digital circuit unit comprises: the interpolation filter of Lian Jieing, sigma-delta modulator, Dynamic matching unit successively; Described sigma-delta modulator is used for when receiving the order of switch audio data, and the signal of the voice data before the switching that the sampling of described interpolation filter is obtained decays to desired value.
5. delta modulation type transducer as claimed in claim 4 is characterized in that described sigma-delta modulator comprises:
One state machine, the signal that is used to control the voice data before the switching that described interpolation filter sampling obtains is decremented to desired value step by step.
6. delta modulation type transducer as claimed in claim 4, it is characterized in that the output of described analog circuit unit is provided with first switching tube, the equivalent capacity of described first switching tube and earphone cord forms parallel-connection structure, when delta modulation type transducer was activated, described first switching tube was connected; Described first switching tube, one end ground connection.
7. delta modulation type transducer as claimed in claim 6, it is characterized in that, described first switching tube is a COMS pipe, the source electrode of described COMS pipe and drain electrode are connected to the two ends of the equivalent capacity of earphone cord, when described delta modulation type transducer was activated, the grid of described COMS pipe was unlocked.
8. delta modulation type transducer as claimed in claim 4, it is characterized in that, the output of described analog circuit unit is provided with the second switch pipe, the equivalent output capacitance of the equivalent capacity of described second switch Guan Yiduan and earphone cord and described delta modulation type transducer forms parallel-connection structure, when delta modulation type transducer was closed, described second switch pipe was connected; Described second switch pipe one end ground connection.
9. delta modulation type transducer as claimed in claim 8, it is characterized in that, described second switch Guan Weiyi COMS pipe, the source electrode of described COMS pipe and drain electrode are connected to the two ends of the equivalent output capacitance of the equivalent capacity of earphone cord and described delta modulation type transducer, when described delta modulation type transducer was closed, the grid of described COMS pipe was unlocked.
10. a multimedia play terminal is characterized in that, comprises just like each described delta modulation type transducer of claim 4 to 7.
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| CN201010190473.4A CN102263557B (en) | 2010-05-31 | 2010-05-31 | Delta modulation type converter and method for eliminating crackle noise thereof |
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| CN201010190473.4A CN102263557B (en) | 2010-05-31 | 2010-05-31 | Delta modulation type converter and method for eliminating crackle noise thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106170113A (en) * | 2016-09-29 | 2016-11-30 | 北京奇艺世纪科技有限公司 | A kind of method and apparatus eliminating noise and electronic equipment |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6163214A (en) * | 1998-01-22 | 2000-12-19 | Lam; Peter Ar-Fu | Analog signal amplifier |
| CN1604479A (en) * | 2003-09-29 | 2005-04-06 | 上海芯华微电子有限公司 | Digital soft switch in D/A converter and using method thereof |
| CN101409560A (en) * | 2008-11-26 | 2009-04-15 | 苏州顺芯半导体有限公司 | Apparatus and method for eliminating blasting noise of digital-analog converter |
-
2010
- 2010-05-31 CN CN201010190473.4A patent/CN102263557B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6163214A (en) * | 1998-01-22 | 2000-12-19 | Lam; Peter Ar-Fu | Analog signal amplifier |
| CN1604479A (en) * | 2003-09-29 | 2005-04-06 | 上海芯华微电子有限公司 | Digital soft switch in D/A converter and using method thereof |
| CN101409560A (en) * | 2008-11-26 | 2009-04-15 | 苏州顺芯半导体有限公司 | Apparatus and method for eliminating blasting noise of digital-analog converter |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106170113A (en) * | 2016-09-29 | 2016-11-30 | 北京奇艺世纪科技有限公司 | A kind of method and apparatus eliminating noise and electronic equipment |
| CN106170113B (en) * | 2016-09-29 | 2020-05-22 | 北京奇艺世纪科技有限公司 | Method and device for eliminating noise and electronic equipment |
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| CN102263557B (en) | 2014-08-20 |
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Denomination of invention: Delta modulation type converter and method for eliminating crackle noise thereof Effective date of registration: 20171102 Granted publication date: 20140820 Pledgee: China Co truction Bank Corp Guangzhou economic and Technological Development Zone sub branch Pledgor: Anyka (Guangzhou) Microelectronics Technology Co., Ltd. Registration number: 2017990001008 |
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Date of cancellation: 20181227 Granted publication date: 20140820 Pledgee: China Co truction Bank Corp Guangzhou economic and Technological Development Zone sub branch Pledgor: Anyka (Guangzhou) Microelectronics Technology Co., Ltd. Registration number: 2017990001008 |
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Denomination of invention: Delta modulation type converter and method for eliminating crackle noise thereof Effective date of registration: 20190130 Granted publication date: 20140820 Pledgee: China Co truction Bank Corp Guangzhou economic and Technological Development Zone sub branch Pledgor: Anyka (Guangzhou) Microelectronics Technology Co., Ltd. Registration number: 2019440000051 |
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Address after: 3 / F, C1 area, innovation building, 182 science Avenue, Science City, Guangzhou, Guangdong 518000 Patentee after: Guangzhou Ankai Microelectronics Co.,Ltd. Address before: 3 / F, C1 area, innovation building, 182 science Avenue, Science City, Guangzhou, Guangdong 518000 Patentee before: ANYKA (GUANGZHOU) MICROELECTRONICS TECHNOLOGY Co.,Ltd. |
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Address after: 510555 No. 107 Bowen Road, Huangpu District, Guangzhou, Guangdong Patentee after: Guangzhou Ankai Microelectronics Co.,Ltd. Address before: 3 / F, C1 area, innovation building, 182 science Avenue, Science City, Guangzhou, Guangdong 518000 Patentee before: Guangzhou Ankai Microelectronics Co.,Ltd. |
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