US5907822A
Expired / Lapsed
US
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Loss tolerant speech decoder for telecommunications
Assignee: Engility LLC
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Filing: 1997-04-04
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Granted: 1999-05-25
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Expires: 2017-04-04
Abstract
Abstract A method and device for extrapolating past signal-history data for insertion into missing data segments in order to conceal digital speech frame errors. The extrapolation method uses past-signal history that is stored in a buffer. The method is implemented with a device that utilizes a finite-impulse response (FIR) multi-layer feed-forward artificial neural network that is trained by back-propagation for one-step extrapolation of speech compression algorithm (SCA) parameters. Once a speech connection has been established, the speech compression algorithm device begins sending encoded speech frames. As the speech frames are received, they are decoded and converted back into speech signal voltages. During the normal decoding process, pre-processing of the required SCA parameters will occur and the results stored in the past-history buffer. If a speech frame is detected to be lost or in error, then extrapolation modules are executed and replacement SCA parameters are generated and sent as the parameters required by the SCA. In this way, the information transfer to the SCA is transparent, and the SCA processing continues as usual. The listener will not normally notice that a speech frame has been lost because of the smooth transition between the last-received, lost, and next-received speech frames.
Inventors
- 👤 Jaime L. Prieto, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 03:41
CPC Classifications
G; G10; G10L; G10L19/00; G10L19/005
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
173 words
A loss-tolerant speech decoder that receives speech frame parameters according to a speech compression algorithm, said decoder comprising: a frame error detector, said frame error detector capable of discriminating between properly received speech frame parameters and parameters that are lost or corrupted, said frame error detector further capable of issuing a signal upon receipt of lost or corrupted speech frame parameters, a parameter decoder, said parameter decoder capable of decoding said received speech frame parameters to make decoded speech frames, a buffer, said buffer used to store a history of said decoded speech frames received by said buffer from said parameter decoder, a speech filter, said speech filter capable of generating replacement speech frame parameters that are written to said parameter decoder upon issuance of said signal from said frame error code detector upon receipt of a lost or corrupted speech frame, wherein said replacement speech frame parameters take the place of lost or corrupted speech frame parameters received by said decoder in order to conceal said lost or corrupted speech frame parameters.
Claim 2
Dependent Claim
173 words
A loss-tolerant speech decoder that receives speech frame parameters according to a speech compression algorithm, said decoder comprising: a frame error detector, said frame error detector capable of discriminating between properly received speech frame parameters and parameters that are lost or corrupted, said frame error detector further capable of issuing a signal upon receipt of lost or corrupted speech frame parameters, a parameter decoder, said parameter decoder capable of decoding said received speech frame parameters to make decoded speech frames, a buffer, said buffer used to store a history of said decoded speech frames received by said buffer from said parameter decoder, a speech filter, said speech filter capable of generating replacement speech frame parameters that are written to said parameter decoder upon issuance of said signal from said frame error code detector upon receipt of a lost or corrupted speech frame, wherein said replacement speech frame parameters take the place of lost or corrupted speech frame parameters received by said decoder in order to conceal said lost or corrupted speech frame parameters.
Claim 3
Dependent Claim
17 words
A speech decoder as in claim 1 wherein said speech filter has a plurality of neural networks.
Claim 4
Dependent Claim
16 words
A speech decoder as in claim 2 wherein said neural networks are multi-layer feed-forward neural networks.
Claim 5
Dependent Claim
18 words
A speech decoder as in claim 3 wherein said neural networks are finite-impulse response multi-layer feed-forward neural networks.
Claim 6
Dependent Claim
17 words
A speech decoder as in claim 2 wherein said neural networks are trained by the back-propagation method.
Claim 7
Dependent Claim
17 words
A speech decoder as in claim 5 wherein said back-propagation training includes the addition of input nodes.
Claim 8
Dependent Claim
24 words
A speech decoder as in claim 2 wherein at least one neural network is designated for the energy characteristics of said speech frame parameters.
Claim 9
Dependent Claim
24 words
A speech decoder as in claim 2 wherein at least one neural network is designated for the voicing characteristics of said speech frame parameters.
Claim 10
Dependent Claim
24 words
A speech decoder as in claim 2 wherein at least one neural network is designated for the pitch characteristics of said speech frame parameters.
Claim 11
Dependent Claim
26 words
A speech decoder as in claim 2 wherein at least one neural network is designated for the low frequency envelope characteristics of said speech frame parameters.
Claim 12
Dependent Claim
26 words
A speech decoder as in claim 2 wherein at least one neural network is designated for the medium frequency envelope characteristics of said speech frame parameters.
Claim 13
Dependent Claim
26 words
A speech decoder as in claim 2 wherein at least one neural network is designated for the high frequency envelope characteristics of said speech frame parameters.
Claim 14
Dependent Claim
29 words
A speech decoder as in claim 2 wherein said speech filter generates replacement speech frame parameters based upon said history of said decoded speech frames stored in said buffer.
Claim 15
Dependent Claim
19 words
A speech decoder as in claim 1 wherein said buffer receives decoded speech frame information from said speech filter.
Claim 16
Dependent Claim
36 words
A speech decoder as in claim 1 wherein a speech compression algorithm synthesizer receives decoded parameters from said parameter decoder and transforms said decoded parameters into speech signal voltages that are then output to a listener.
Claim 17
Dependent Claim
45 words
A speech decoder as in claim 1 wherein said replacement speech frame parameters from said speech filter are reformatted in a back-calculation device to conform to an input format of said parameter decoder before said replacement speech frame parameters are written to said parameter decoder.
Claim 18
Dependent Claim
38 words
A speech decoder as in claim 1 wherein said decoded parameters received by said parameter decoder are first reformatted in a calculation device to conform to a format acceptable to said buffer before being stored in said buffer.
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) | 2002-05-24 | 2002-11-23 | 2003-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-05-24 | 2006-11-23 | 2007-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-05-24 | 2010-11-23 | 2011-05-25 | $7700.00 | Window Closed / Lapsed |