US5774567A
Expired / Lapsed
US
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Audio codec with digital level adjustment and flexible channel assignment
Assignee: Apple Inc
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Filing: 1995-04-11
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Granted: 1998-06-30
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Expires: 2015-04-11
Abstract
Abstract An audio codec capable of handling complex control and routing of numerous sound inputs is described. The complex control and routing is obtained by weighting various sound inputs in accordance with weighting values and then digitally mixing the weighted sound inputs together. The invention facilitates construction of the audio codec with mainly fixed gain amplifiers, instead of variable gain preamplifiers, thereby saving a large amount of die space and reducing time needed for testing.
Inventors
- 👤 Lawrence F. Heyl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:19
CPC Classifications
H; H04; H04S; H04S1/00; H04S1/007
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
172 words
An apparatus for coding and decoding sound signals, said apparatus receiving a plurality of input sound signals on input signal lines and producing a plurality of digital output signals on output signal lines, said apparatus comprising: a plurality of delta sigma modulators, each of said delta sigma modulators receiving a different one of the input sound signals and producing a serial digital sound signal having pulses determined by the corresponding input sound signal; a plurality of level adjustment circuits, each of said level adjustment circuits corresponding to one of said delta sigma modulators and receiving the serial digital sound signal produced thereby, and each of said level adjustment circuits receiving a predetermined weight value for each of the output signal lines and respectively outputting a weighted digital signal for each of the output signal lines based on the corresponding weight value, the predetermined weight values being independently selectable; and a plurality of combiners, each of said combiners respectively combining the outputted weighted digital signals corresponding to one of the output signal lines.
Claim 2
Independent Claim
172 words
An apparatus for coding and decoding sound signals, said apparatus receiving a plurality of input sound signals on input signal lines and producing a plurality of digital output signals on output signal lines, said apparatus comprising: a plurality of delta sigma modulators, each of said delta sigma modulators receiving a different one of the input sound signals and producing a serial digital sound signal having pulses determined by the corresponding input sound signal; a plurality of level adjustment circuits, each of said level adjustment circuits corresponding to one of said delta sigma modulators and receiving the serial digital sound signal produced thereby, and each of said level adjustment circuits receiving a predetermined weight value for each of the output signal lines and respectively outputting a weighted digital signal for each of the output signal lines based on the corresponding weight value, the predetermined weight values being independently selectable; and a plurality of combiners, each of said combiners respectively combining the outputted weighted digital signals corresponding to one of the output signal lines.
Claim 3
Independent Claim
198 words
An apparatus for coding and decoding sound signals, said apparatus receiving a plurality of input sound signals on input signal lines and producing a plurality of digital output signals on output signal lines, said apparatus comprising: a plurality of delta sigma modulators, each of said delta sigma modulators receiving a different one of the input sound signals and producing a serial digital sound signal having pulses determined by the corresponding input sound signal; a plurality of level adjustment circuits, each of said level adjustment circuits corresponding to one of said delta sigma modulators and receiving the serial digital sound signal produced thereby, and each of said level adjustment circuits receiving a predetermined weight value for each of the output signal lines and respectively outputting a weighted digital signal for each of the output signal lines based on the corresponding weight value and a plurality of combiners, each of said combiners respectively combining the outputted weighted digital signals corresponding to one of the output signal lines; wherein each of the weighted digital signals output from each of said level adjustment circuits comprises one of the corresponding predetermined weight value and a negative representation of the corresponding predetermined weight value.
Claim 4
Independent Claim
198 words
An apparatus for coding and decoding sound signals, said apparatus receiving a plurality of input sound signals on input signal lines and producing a plurality of digital output signals on output signal lines, said apparatus comprising: a plurality of delta sigma modulators, each of said delta sigma modulators receiving a different one of the input sound signals and producing a serial digital sound signal having pulses determined by the corresponding input sound signal; a plurality of level adjustment circuits, each of said level adjustment circuits corresponding to one of said delta sigma modulators and receiving the serial digital sound signal produced thereby, and each of said level adjustment circuits receiving a predetermined weight value for each of the output signal lines and respectively outputting a weighted digital signal for each of the output signal lines based on the corresponding weight value and a plurality of combiners, each of said combiners respectively combining the outputted weighted digital signals corresponding to one of the output signal lines; wherein each of the weighted digital signals output from each of said level adjustment circuits comprises one of the corresponding predetermined weight value and a negative representation of the corresponding predetermined weight value.
Claim 5
Dependent Claim
52 words
An apparatus as recited in claim 1, wherein each of said level adjustment circuits comprises means for selecting, for each of the weighted digital signals, one of the corresponding predetermined weight value and a negative representation of the corresponding predetermined weight value based on the sign of the serial digital sound signal.
Claim 6
Dependent Claim
32 words
An apparatus as recited in claim 3, wherein said combiners are adders, and each of said adders respectively adds the outputted weighted digital signals corresponding to each of the output signal lines.
Claim 7
Independent Claim
216 words
An apparatus for coding and decoding sound signals, said apparatus receiving a plurality of input sound signals on input signal lines and producing a plurality of digital output signals on output signal lines, said apparatus comprising: a plurality of delta sigma modulators, each of said delta sigma modulators receiving a different one of the input sound signals and producing a serial digital sound signal having pulses determined by the corresponding input sound signal; a plurality of level adjustment circuits, each of said level adjustment circuits corresponding to one of said delta sigma modulators and receiving the serial digital sound signal produced thereby, and each of said level adjustment circuits receiving a predetermined weight value for each of the output signal lines and respectively outputting a weighted digital signal for each of the output signal lines based on the corresponding weight value; and a plurality of combiners, each of said combiners respectively combining the outputted weighted digital signals corresponding to one of the output signal lines, wherein each of said level adjustment circuits comprise a plurality of registers, each of said registers storing one of the predetermined weight values associated with said level adjustment circuit, and each of the predetermined weight values within each of said registers corresponding to a different one of the output signal lines.
Claim 8
Independent Claim
216 words
An apparatus for coding and decoding sound signals, said apparatus receiving a plurality of input sound signals on input signal lines and producing a plurality of digital output signals on output signal lines, said apparatus comprising: a plurality of delta sigma modulators, each of said delta sigma modulators receiving a different one of the input sound signals and producing a serial digital sound signal having pulses determined by the corresponding input sound signal; a plurality of level adjustment circuits, each of said level adjustment circuits corresponding to one of said delta sigma modulators and receiving the serial digital sound signal produced thereby, and each of said level adjustment circuits receiving a predetermined weight value for each of the output signal lines and respectively outputting a weighted digital signal for each of the output signal lines based on the corresponding weight value; and a plurality of combiners, each of said combiners respectively combining the outputted weighted digital signals corresponding to one of the output signal lines, wherein each of said level adjustment circuits comprise a plurality of registers, each of said registers storing one of the predetermined weight values associated with said level adjustment circuit, and each of the predetermined weight values within each of said registers corresponding to a different one of the output signal lines.
Claim 9
Dependent Claim
32 words
An apparatus as recited in claim 5, wherein said combiners are adders, and each of said adders respectively adds the outputted weighted digital signals corresponding to each of the output signal lines.
Claim 10
Dependent Claim
68 words
An apparatus as recited in claim 1, wherein each of said level adjustment circuits comprise a register file, said register file being associated with one of said delta sigma modulators and storing a plurality of the predetermined weight values, each of the predetermined weight values within said register file corresponding to a different output signal line, and said register file producing a plurality of the weighted digital signals.
Claim 11
Dependent Claim
32 words
An apparatus as recited in claim 7, wherein said combiners are adders, and each of said adders respectively adds the outputted weighted digital signals corresponding to each of the output signal lines.
Claim 12
Dependent Claim
32 words
An apparatus as recited in claim 1, wherein said apparatus further comprises at least one digital-to-analog converter for converting at least one of the weighted digital signals to an analog output signal.
Claim 13
Independent Claim
176 words
A method for coding sound signals for digital sound output signal lines, comprising: (a) receiving analog sound signals, each of the input sound signals being received on a different input signal line; (b) producing digital sound signals from each of the analog sound signals, each of the digital sound signals corresponding to one of the analog sound signals and including a serial stream of pulses determined based on the amplitude of the analog sound signal corresponding thereto; (c) obtaining independently selectable digital weight values for each of the digital sound signals, the weight values for each of the digital sound signals including a weight value for each of the digital sound output signal lines; (d) producing weighted digital sound signals for each of the digital sound output signal lines based on the digital sound signals and the weight values; and (e) for each of the digital sound output signal lines, summing the weighted digital sound signals directed to each of the digital sound output signal lines, thereby producing signals for the digital sound output signal lines.
Claim 14
Independent Claim
176 words
A method for coding sound signals for digital sound output signal lines, comprising: (a) receiving analog sound signals, each of the input sound signals being received on a different input signal line; (b) producing digital sound signals from each of the analog sound signals, each of the digital sound signals corresponding to one of the analog sound signals and including a serial stream of pulses determined based on the amplitude of the analog sound signal corresponding thereto; (c) obtaining independently selectable digital weight values for each of the digital sound signals, the weight values for each of the digital sound signals including a weight value for each of the digital sound output signal lines; (d) producing weighted digital sound signals for each of the digital sound output signal lines based on the digital sound signals and the weight values; and (e) for each of the digital sound output signal lines, summing the weighted digital sound signals directed to each of the digital sound output signal lines, thereby producing signals for the digital sound output signal lines.
Claim 15
Independent Claim
184 words
A method for coding sound signals for digital sound output signal lines, comprising: (a) receiving analog sound signals; (b) producing digital sound signals from each of the analog sound signals, each of the digital sound signals corresponding to one of the analog sound signals and including a serial stream of pulses determined based on the amplitude of the analog sound signal corresponding thereto; (c) obtaining weight values for each of the digital sound signals, the weight values for each of the digital sound signals including a weight value for each of the digital sound output signal lines; (d) producing weighted digital sound signals for each of the digital sound output signal lines based on the digital sound signals and the weight values, for each of the digital sound signals said producing the corresponding weight value or its complement for each of the digital sound output signal lines; and (e) for each of the digital sound output signal lines, summing the weighted digital sound signals directed to each of the digital sound output signal lines, thereby producing signals for the digital sound output signal lines.
Claim 16
Independent Claim
184 words
A method for coding sound signals for digital sound output signal lines, comprising: (a) receiving analog sound signals; (b) producing digital sound signals from each of the analog sound signals, each of the digital sound signals corresponding to one of the analog sound signals and including a serial stream of pulses determined based on the amplitude of the analog sound signal corresponding thereto; (c) obtaining weight values for each of the digital sound signals, the weight values for each of the digital sound signals including a weight value for each of the digital sound output signal lines; (d) producing weighted digital sound signals for each of the digital sound output signal lines based on the digital sound signals and the weight values, for each of the digital sound signals said producing the corresponding weight value or its complement for each of the digital sound output signal lines; and (e) for each of the digital sound output signal lines, summing the weighted digital sound signals directed to each of the digital sound output signal lines, thereby producing signals for the digital sound output signal lines.
Claim 17
Dependent Claim
43 words
A method as recited in claim 11, wherein said producing (d) outputs the corresponding weight value if the corresponding digital sound signal is greater than zero, and outputs the complemented weight value if the corresponding digital sound signal is not greater than zero.
Claim 18
Dependent Claim
21 words
A method as recited in claim 10, wherein the weight values are being determined so as to provide a logarithmic response.
References Cited (Backward Citations)
US5119422A
Cited
US5208594A
Cited
US5196852A
Cited
US5528239A
Cited
US5533112A
Cited
US5483528A
Cited
US5647008A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-06-29 | 2001-12-29 | 2002-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-06-29 | 2005-12-29 | 2006-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-06-29 | 2009-12-29 | 2010-06-30 | $7700.00 | Window Closed / Lapsed |