Patent US5535299A successfully refreshed from Google Patents.
US5535299A
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Adaptive error control for ADPCM speech coders
Assignee: Cirrus Logic Inc
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Filing: 1993-11-02
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Granted: 1996-07-09
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Expires: 2013-11-02
Abstract
Abstract Methods and apparatus for improving the perceived quality of ADPCM encoded signals by magnitude limiting samples of the ADPCM encoded signals prior to the decoding of samples of the ADPCM encoded signals, preferably, a sample of the ADPCM encoded signal is magnitude limited only if a receive error is detected for the sample.
Inventors
- 👤 Neal K. Riedel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 19:04
CPC Classifications
G; G10; G10L; G10L25/00; G10L25/78; G10L19/00; G10L19/04
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
101 words
A method of improving a perceived voice quality of an ADPCM encoded signal having segments received from an imperfect communications channel, said method comprising the steps of: a) converting a received segment of the ADPCM encoded signal to ADPCM samples; b) determining the magnitude of the ADPCM samples; c) replacing the value of a one ADPCM sample with a first predetermined value if the magnitude of the one ADPCM sample is greater than a second predetermined value, the magnitude of the first predetermined value being greater than zero; and d) after step c), decoding the ADPCM samples using a ADPCM decoder.
Claim 2
Independent Claim
101 words
A method of improving a perceived voice quality of an ADPCM encoded signal having segments received from an imperfect communications channel, said method comprising the steps of: a) converting a received segment of the ADPCM encoded signal to ADPCM samples; b) determining the magnitude of the ADPCM samples; c) replacing the value of a one ADPCM sample with a first predetermined value if the magnitude of the one ADPCM sample is greater than a second predetermined value, the magnitude of the first predetermined value being greater than zero; and d) after step c), decoding the ADPCM samples using a ADPCM decoder.
Claim 3
Dependent Claim
86 words
A method according to claim 1, wherein step c) comprises: i) determining, as a function of the received segment of the ADPCM encoded signal, reliability of the received segment; and ii) replacing the value of a one ADPCM sample with a first predetermined value if the magnitude of the one ADPCM sample is greater than a second predetermined value as a function of determined reliability of the corresponding received segment of the ADPCM encoded signal, the magnitude of the first predetermined value being greater than zero.
Claim 4
Dependent Claim
65 words
A method according to claim 2, wherein step ii) comprises: replacing the value of a one ADPCM sample with a first predetermined value if the magnitude of the one ADPCM sample is greater than a second predetermined value and the determination of the reliability of the corresponding segment of the ADPCM encoded signal indicates that a received signal error was detected for the received segment.
Claim 5
Dependent Claim
46 words
A method according to claim 3, said method further comprising the steps of: determining whether the received segment of the ADPCM encoded signal was missed; and replacing the corresponding ADPCM samples with ADPCM encoded silence if the received segment of the ADPCM encoded signal was missed.
Claim 6
Dependent Claim
87 words
A method according to claim 1, wherein step c) comprises: i) determining, as a function of the received segment of the ADPCM encoded signal, whether the received segment is modem or voiceband data; and ii) replacing the value of a one ADPCM sample with a first predetermined value if the magnitude of the one ADPCM sample is greater than a second predetermined value and the received segment was not determined to be modem or voiceband data, the magnitude of the first predetermined value being greater than zero.
Claim 7
Dependent Claim
29 words
A method according to claim 5, wherein step i) comprises: determining, as a function of system parameters of the decoder, whether the received segment is modem or voiceband data.
Claim 8
Dependent Claim
32 words
A method according to claim 5, wherein step i) comprises: determining, as a function of system parameters of the decoder and an encoder, whether the received segment is modem or voiceband data.
Claim 9
Dependent Claim
34 words
A method according to claim 5, wherein step i) comprises: determining, as a function of transmitted segments of an ADPCM encoded signal of an encoder, whether the received segment is modem or voiceband data.
Claim 10
Dependent Claim
99 words
A method according to claim 5, wherein step ii) comprises: iii) determining, as a function of the received segment of the ADPCM encoded signal, reliability of the received segment; and iv) replacing the value of a one ADPCM sample with a first predetermined value if the magnitude of the one ADPCM sample is greater than a second predetermined value and the received segment was not determined to be modem or voiceband data as a function of determined reliability of the corresponding received segment of the ADPCM encoded signal, the magnitude of the first predetermined value being greater than zero.
Claim 11
Dependent Claim
88 words
A method according to claim 9, wherein step iv) comprises: replacing the value of a one ADPCM sample with a first predetermined value if the magnitude of the one ADPCM sample is greater than a second predetermined value, the received segment was not determined to be modem or voiceband data, and the determination of the reliability of the corresponding segment of the ADPCM encoded signal indicates that a received signal error was detected for the received segment, the magnitude of the first predetermined value being greater than zero.
Claim 12
Dependent Claim
46 words
A method according to claim 10, said method further comprising the steps of: determining whether the received segment of the ADPCM encoded signal was missed; and replacing the corresponding ADPCM samples with ADPCM encoded silence if the received segment of the ADPCM encoded signal was missed.
Claim 13
Independent Claim
104 words
An apparatus for improving a perceived voice quality of an ADPCM encoded signal having segments received from an imperfect communications channel, said apparatus comprising: means for converting a received segment of the ADPCM encoded signal to ADPCM samples; means for determining the magnitude of the ADPCM samples; replacement means for replacing the value of a one ADPCM sample with a first predetermined value if the magnitude of the one ADPCM sample is greater than a second predetermined value, the magnitude of the first predetermined value being greater than zero; and an ADPCM decoder, the decoder decoding ADPCM samples after processing by the replacement means.
Claim 14
Independent Claim
104 words
An apparatus for improving a perceived voice quality of an ADPCM encoded signal having segments received from an imperfect communications channel, said apparatus comprising: means for converting a received segment of the ADPCM encoded signal to ADPCM samples; means for determining the magnitude of the ADPCM samples; replacement means for replacing the value of a one ADPCM sample with a first predetermined value if the magnitude of the one ADPCM sample is greater than a second predetermined value, the magnitude of the first predetermined value being greater than zero; and an ADPCM decoder, the decoder decoding ADPCM samples after processing by the replacement means.
Claim 15
Dependent Claim
91 words
An apparatus according to claim 12, wherein said replacement means includes: means for determining, as a function of the received segment of the ADPCM encoded signal, reliability of the received segment; and reliability replacement means for replacing the value of a one ADPCM sample with a first predetermined value if the magnitude of the one ADPCM sample is greater than a second predetermined value as a function of determined reliability of the corresponding received segment of the ADPCM encoded signal, the magnitude of the first predetermined value being greater than zero.
Claim 16
Dependent Claim
69 words
An apparatus according to claim 13, wherein said reliability replacement means includes: means for replacing the value of a one ADPCM sample with a first predetermined value if the magnitude of the one ADPCM sample is greater than a second predetermined value and the determination of the reliability of the corresponding segment of the ADPCM encoded signal indicates that a received signal error was detected for the received segment.
Claim 17
Dependent Claim
47 words
An apparatus according to claim 14, said apparatus further comprising: means for determining whether the received segment of the ADPCM encoded signal was missed; and means for replacing the corresponding ADPCM samples with ADPCM encoded silence if the received segment of the ADPCM encoded signal was missed.
Claim 18
Dependent Claim
94 words
An apparatus according to claim 12, wherein said replacement means includes: voiceband determination means for determining, as a function of the received segment of the ADPCM encoded signal, whether the received segment is modem or voiceband data; and voiceband replacement means for replacing the value of a one ADPCM sample with a first predetermined value if the magnitude of the one ADPCM sample is greater than a second predetermined value and the received segment was not determined to be modem or voiceband data, the magnitude of the first predetermined value being greater than zero.
Claim 19
Dependent Claim
33 words
An apparatus according to claim 16, wherein said voiceband determination means includes: means for determining, as a function of system parameters of the decoder, whether the received segment is modem or voiceband data.
Claim 20
Dependent Claim
36 words
An apparatus according to claim 16, wherein said voiceband determination means includes: means for determining, as a function of system parameters of the decoder and an encoder, whether the received segment is modem or voiceband data.
Claim 21
Dependent Claim
38 words
An apparatus according to claim 16, wherein said voiceband determination means includes: means for determining, as a function of transmitted segments of an ADPCM encoded signal of an encoder, whether the received segment is modem or voiceband data.
Claim 22
Dependent Claim
106 words
An apparatus according to claim 19, wherein said voiceband replacement means includes: means for determining, as a function of the received segment of the ADPCM encoded signal, reliability of the received segment; and reliability voiceband replacement means for replacing the value of a one ADPCM sample with a first predetermined value if the magnitude of the one ADPCM sample is greater than a second predetermined value and the received segment was not determined to be modem or voiceband data as a function of determined reliability of the corresponding received segment of the ADPCM encoded signal, the magnitude of the first predetermined value being greater than zero.
Claim 23
Dependent Claim
93 words
An apparatus according to claim 20, wherein said reliability voiceband replacement means includes: means for replacing the value of a one ADPCM sample with a first predetermined value if the magnitude of the one ADPCM sample is greater than a second predetermined value, the received segment was not determined to be modem or voiceband data, and the determination of the reliability of the corresponding segment of the ADPCM encoded signal indicates that a received signal error was detected for the received segment, the magnitude of the first predetermined value being greater than zero.
Claim 24
Dependent Claim
47 words
An apparatus according to claim 21, said apparatus further comprising: means for determining whether the received segment of the ADPCM encoded signal was missed; and means for replacing the corresponding ADPCM samples with ADPCM encoded silence if the received segment of the ADPCM encoded signal was missed.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-07-09 | 2000-01-08 | 2000-07-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-07-09 | 2004-01-08 | 2004-07-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-07-09 | 2008-01-08 | 2008-07-09 | $7700.00 | Window Closed / Lapsed |