US5572622A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rejected frame concealment
Assignee: Telefonaktiebolaget LM Ericsson AB
•
Filing: 1994-06-10
•
Granted: 1996-11-05
•
Expires: 2014-06-10
Abstract
Abstract A method and apparatus for improving the decoding of audio signals is disclosed. In a receiver of a frame based radio communication system, rejected frames are concealed according to a first algorithm if the last accepted frame was a speech frame and according to a second algorithm if the last accepted frame was a frame containing background sounds.
Inventors
- 👤 Karl T. Wigren
- 👤 Rolf A. Bergstrom
- 👤 Fredrik K. J. Jansson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 17:43
CPC Classifications
H; H04; H04L; H04L1/00; H04L1/004; H04L1/0056; H04L1/0071; G; G10; G10L; G10L19/00; G10L19/005; G10L25/00; G10L25/78; G10L25/84
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
125 words
A method in a frame based radio communication system, for concealing rejected frames in a speech decoder of a receiver, which speech decoder is of the source-filter type and is controlled by received parameters representing audio signals transmitted over a communication channel on a frame by frame basis, said method comprising: (a) accepting or rejecting received frames depending on whether the parameters contained therein are considered to represent proper audio signals; (b) detecting whether accepted frames represent primarily speech or background sounds and; (c) concealing rejected frames by updating the parameters contained therein in accordance with a first concealing algorithm if the last accepted frame primarily represented speech and in accordance with a second concealing algorithm if the last accepted frame contained primarily background sounds.
Claim 2
Independent Claim
125 words
A method in a frame based radio communication system, for concealing rejected frames in a speech decoder of a receiver, which speech decoder is of the source-filter type and is controlled by received parameters representing audio signals transmitted over a communication channel on a frame by frame basis, said method comprising: (a) accepting or rejecting received frames depending on whether the parameters contained therein are considered to represent proper audio signals; (b) detecting whether accepted frames represent primarily speech or background sounds and; (c) concealing rejected frames by updating the parameters contained therein in accordance with a first concealing algorithm if the last accepted frame primarily represented speech and in accordance with a second concealing algorithm if the last accepted frame contained primarily background sounds.
Claim 3
Dependent Claim
24 words
The method of claim 1, wherein said second concealing algorithm comprises locking filter and gain parameters to their values in the last accepted frame.
Claim 4
Dependent Claim
33 words
The method of claim 2, wherein said second concealing algorithm decreases the output level of the audio signal from said speech decoder when a first predetermined number of consecutive frames have been rejected.
Claim 5
Dependent Claim
36 words
The method of claim 3, wherein said second concealing algorithm repeatedly decreases the output level of the audio signal from said speech decoder each time said first predetermined number of further consecutive frames have been rejected.
Claim 6
Dependent Claim
27 words
The method of claim 1, wherein said first concealing algorithm interpolates predetermined received parameters from the first rejected frame with corresponding parameters from the last accepted frame.
Claim 7
Dependent Claim
49 words
The method of claim 5, wherein said first concealing algorithm interpolates predetermined received parameters from the current rejected frame with corresponding parameters from the previous rejected frame and decreases the output level of the audio signal from said speech decoder if at least two consecutive frames have been rejected.
Claim 8
Dependent Claim
30 words
The method of claim 6, wherein said first concealing algorithm mutes the output signal from said speech decoder if a second predetermined number of further consecutive frames have been rejected.
Claim 9
Dependent Claim
34 words
The method of claim 1, wherein transmitted parameters are encoded in accordance with a first encoding algorithm if they represent speech and in accordance with a second encoding algorithm if they represent background sounds.
Claim 10
Dependent Claim
34 words
The method of claim 1, wherein received parameters are decoded in accordance with a first decoding algorithm if they represent speech and in accordance with a second decoding algorithm if they represent background sounds.
Claim 11
Independent Claim
130 words
An apparatus in a frame based radio communication system, for concealing rejected frames in a speech decoder of a receiver, which speech decoder is of the source-filter type and is controlled by received parameters representing audio signals transmitted over a communication channel on a frame by frame basis, said apparatus comprising: (a) means for accepting or rejecting received frames depending on whether the parameters contained therein are considered to represent proper audio signals; (b) means for detecting whether accepted frames represent primarily speech or background sounds; (c) means for concealing rejected frames by updating the parameters contained therein in accordance with a first concealing algorithm if the last accepted frame primarily represented speech and in accordance with a second concealing algorithm if the last accepted frame contained primarily background sounds.
Claim 12
Independent Claim
130 words
An apparatus in a frame based radio communication system, for concealing rejected frames in a speech decoder of a receiver, which speech decoder is of the source-filter type and is controlled by received parameters representing audio signals transmitted over a communication channel on a frame by frame basis, said apparatus comprising: (a) means for accepting or rejecting received frames depending on whether the parameters contained therein are considered to represent proper audio signals; (b) means for detecting whether accepted frames represent primarily speech or background sounds; (c) means for concealing rejected frames by updating the parameters contained therein in accordance with a first concealing algorithm if the last accepted frame primarily represented speech and in accordance with a second concealing algorithm if the last accepted frame contained primarily background sounds.
Claim 13
Dependent Claim
27 words
The apparatus of claim 10, comprising means for performing said second concealing algorithm by locking filter and gain parameters to their values in the last accepted frame.
Claim 14
Dependent Claim
37 words
The apparatus of claim 11, wherein said means for performing said second concealing algorithm decreases the output level of the audio signal from said speech decoder when a first predetermined number of consecutive frames have been rejected.
Claim 15
Dependent Claim
40 words
The apparatus of claim 12, wherein said means for performing said second concealing algorithm repeatedly decreases the output level of the audio signal from said speech decoder each time said first predetermined number of further consecutive frames have been rejected.
Claim 16
Dependent Claim
31 words
The apparatus of claim 10, comprising means for performing said first concealing algorithm by interpolating predetermined received parameters in the first rejected frame with corresponding parameters from the last accepted frame.
Claim 17
Dependent Claim
53 words
The apparatus of claim 14, wherein said means for performing said first concealing algorithm interpolates predetermined received parameters in the current rejected frame with corresponding parameters from the previous rejected frame and decreases the output level of the audio signal from said speech decoder if at least two consecutive frames have been rejected.
Claim 18
Dependent Claim
34 words
The apparatus of claim 15, wherein said means for performing said first concealing algorithm mutes the output signal from said speech decoder if a second predetermined number of further consecutive frames have been rejected.
Claim 19
Dependent Claim
35 words
The apparatus of claim 10, comprising means for encoding transmitted parameters in accordance with a first encoding algorithm if they represent speech and in accordance with a second encoding algorithm if they represent background sounds.
Claim 20
Dependent Claim
35 words
The apparatus of claim 10, comprising means for decoding received parameters in accordance with a first decoding algorithm if they represent speech and in accordance with a second decoding algorithm if they represent background sounds.
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) | 1999-11-05 | 2000-05-06 | 2000-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-11-05 | 2004-05-06 | 2004-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-11-05 | 2008-05-06 | 2008-11-05 | $7700.00 | Window Closed / Lapsed |