US5790632A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for echo canceling accounting for companding induced quantization error
Assignee: Qualcomm Inc
•
Filing: 1996-05-21
•
Granted: 1998-08-04
•
Expires: 2016-05-21
Abstract
Abstract An improved method and apparatus for canceling echo is disclosed. The echo canceller of the present invention compensates for the existence of quantization error in the echo signal that does not exist in the reference signal by introducing the quantization effects into the reference signal. The quantization effects are typically companding quantization errors caused by the A-law and μ-law quantizers prevalent in digital communications equipment.
Inventors
- 👤 Franklin P. Antonio
- 👤 Andrew P. DeJaco
- 👤 Gilbert C. Sih
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:22
CPC Classifications
H; H04; H04M; H04M9/00; H04M9/08; H04M9/082; B; B64; B64G; B64G1/00; B64G1/002; B64G1/005; H04B; H04B3/00; H04B3/02; H04B3/20; H04B3/23
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
102 words
An echo canceller comprising: quantization compensation means for receiving a forward direction signal and encoding said forward direction signal in accordance with a predetermined quantization transformation to provide a quantization compensated signal, said quantization transformation compensating for compression and expansion (companding) signal processing operations; and adaptive filter means for receiving said quantization compensated signal and a reverse direction signal containing an echo signal of said forward direction signal and for generating a companding compensated echo estimate in accordance with said quantization compensated signal, said companding estimated echo estimate to be subtracted from said reverse direction signal to provide an echo canceled signal.
Claim 2
Dependent Claim
102 words
An echo canceller comprising: quantization compensation means for receiving a forward direction signal and encoding said forward direction signal in accordance with a predetermined quantization transformation to provide a quantization compensated signal, said quantization transformation compensating for compression and expansion (companding) signal processing operations; and adaptive filter means for receiving said quantization compensated signal and a reverse direction signal containing an echo signal of said forward direction signal and for generating a companding compensated echo estimate in accordance with said quantization compensated signal, said companding estimated echo estimate to be subtracted from said reverse direction signal to provide an echo canceled signal.
Claim 3
Dependent Claim
16 words
The apparatus of claim 1 wherein said quantization transformation is the quantization of a digital companding.
Claim 4
Dependent Claim
12 words
The apparatus of claim 2 wherein said digital companding is A-law companding.
Claim 5
Dependent Claim
12 words
The apparatus of claim 2 wherein said digital companding is μ-law companding.
Claim 6
Dependent Claim
14 words
The apparatus of claim 1 wherein said echo signal is a network echo signal.
Claim 7
Dependent Claim
14 words
The apparatus of claim 1 wherein said echo signal is an acoustic echo signal.
Claim 8
Dependent Claim
22 words
The apparatus of claim 1 wherein said echo signal is a combination of an acoustic echo signal and a network echo signal.
Claim 9
Dependent Claim
15 words
The apparatus of claim 1 wherein said echo canceller is in a mobile phone environment.
Claim 10
Dependent Claim
20 words
The apparatus of claim 8 wherein said echo canceller is in a code division multiple access (CDMA) mobile phone environment.
Claim 11
Dependent Claim
16 words
The apparatus of claim 1 wherein said echo canceller is in a wireless local loop environment.
Claim 12
Dependent Claim
15 words
The apparatus of claim 10 wherein said forward direction signal is provided by a vocoder.
Claim 13
Dependent Claim
124 words
An echo canceller comprising: a quantization compensator having an input for receiving a forward direction signal and encoding said forward direction signal in accordance with a predetermined quantization transformation and having an output to provide a quantization compensated signal, said quantization transformation compensating for compression and expansion (companding) signal processing operations; and an adaptive filter having an input for receiving said quantization compensated signal and an output connected to a summing element, said adaptive filter generating a companding compensated echo estimate in accordance with said quantization compensated signal and providing said companding compensated echo estimate to said summing element disposed to remove said companding compensated echo estimate from a reverse direction signal, said summing element having an output for providing an echo canceled signal.
Claim 14
Dependent Claim
124 words
An echo canceller comprising: a quantization compensator having an input for receiving a forward direction signal and encoding said forward direction signal in accordance with a predetermined quantization transformation and having an output to provide a quantization compensated signal, said quantization transformation compensating for compression and expansion (companding) signal processing operations; and an adaptive filter having an input for receiving said quantization compensated signal and an output connected to a summing element, said adaptive filter generating a companding compensated echo estimate in accordance with said quantization compensated signal and providing said companding compensated echo estimate to said summing element disposed to remove said companding compensated echo estimate from a reverse direction signal, said summing element having an output for providing an echo canceled signal.
Claim 15
Dependent Claim
16 words
The apparatus of claim 12 wherein said quantization transformation is the quantization of a digital companding.
Claim 16
Dependent Claim
12 words
The apparatus of claim 13 wherein said digital companding is A-law companding.
Claim 17
Dependent Claim
12 words
The apparatus of claim 13 wherein said digital companding is μ-law companding.
Claim 18
Dependent Claim
14 words
The apparatus of claim 12 wherein said echo signal is a network echo signal.
Claim 19
Dependent Claim
14 words
The apparatus of claim 12 wherein said echo signal is an acoustic echo signal.
Claim 20
Dependent Claim
22 words
The apparatus of claim 12 wherein said echo signal is a combination of an acoustic echo signal and a network echo signal.
Claim 21
Dependent Claim
15 words
The apparatus of claim 12 wherein said echo canceller is in a mobile phone environment.
Claim 22
Dependent Claim
20 words
The apparatus of claim 19 wherein said echo canceller is in a code division multiple access (CDMA) mobile phone environment.
Claim 23
Dependent Claim
16 words
The apparatus of claim 12 wherein said echo canceller is in a wireless local loop environment.
Claim 24
Dependent Claim
15 words
The apparatus of claim 12 wherein said forward direction signal is provided by a vocoder.
Claim 25
Independent Claim
86 words
A method of echo canceling comprising the steps of: receiving a forward direction signal; encoding said forward direction signal in accordance with a predetermined quantization transformation to provide a quantization compensated signal, said quantization transformation compensating for compression and expansion (companding) signal processing operations; providing said quantization compensated signal to an input of an adaptive filter for generating a companding compensated echo estimate in accordance with said quantization compensated signal; and removing said companding compensated echo estimate from a reverse direction signal containing an echo signal.
Claim 26
Independent Claim
86 words
A method of echo canceling comprising the steps of: receiving a forward direction signal; encoding said forward direction signal in accordance with a predetermined quantization transformation to provide a quantization compensated signal, said quantization transformation compensating for compression and expansion (companding) signal processing operations; providing said quantization compensated signal to an input of an adaptive filter for generating a companding compensated echo estimate in accordance with said quantization compensated signal; and removing said companding compensated echo estimate from a reverse direction signal containing an echo signal.
Claim 27
Dependent Claim
16 words
The method of claim 23 wherein said quantization transformation is the quantization of a digital companding.
Claim 28
Dependent Claim
12 words
The method of claim 24 wherein said digital companding is A-law companding.
Claim 29
Dependent Claim
12 words
The method of claim 24 wherein said digital companding is μ-law companding.
Claim 30
Dependent Claim
14 words
The method of claim 23 wherein said echo signal is a network echo signal.
Claim 31
Dependent Claim
14 words
The method of claim 23 wherein said echo signal is an acoustic echo signal.
Claim 32
Dependent Claim
22 words
The method of claim 23 wherein said echo signal is a combination of an acoustic echo signal and a network echo signal.
Claim 33
Dependent Claim
17 words
The method of claim 23 wherein said method of echo canceling is in a mobile phone environment.
Claim 34
Dependent Claim
22 words
The method of claim 30 wherein said method of echo canceling is in a code division multiple access (CDMA) mobile phone environment.
Claim 35
Dependent Claim
18 words
The method of claim 23 wherein said method of echo canceling is in a wireless local loop environment.
Claim 36
Dependent Claim
15 words
The method of claim 23 wherein said forward direction signal is provided by a vocoder.
Claim 37
Dependent Claim
94 words
An echo canceller comprising: quantization compensation means for receiving a forward direction signal and encoding said forward direction signal in accordance with a predetermined quantization transformation to provide a quantization compensated signal; and adaptive filter means for receiving said quantization compensated signal and a reverse direction signal containing an echo signal, said echo signal resulting from propagation of a companding quantized signal of said forward direction signal over an echo channel and for generating an echo estimate in accordance with said quantization compensated signal and removing said echo estimate from said reverse direction signal.
Claim 38
Dependent Claim
94 words
An echo canceller comprising: quantization compensation means for receiving a forward direction signal and encoding said forward direction signal in accordance with a predetermined quantization transformation to provide a quantization compensated signal; and adaptive filter means for receiving said quantization compensated signal and a reverse direction signal containing an echo signal, said echo signal resulting from propagation of a companding quantized signal of said forward direction signal over an echo channel and for generating an echo estimate in accordance with said quantization compensated signal and removing said echo estimate from said reverse direction signal.
References Cited (Backward Citations)
US4686703A
Cited
US4827472A
Cited
US4764955A
Cited
US4782525A
Cited
US4823342A
Cited
US4697261A
Cited
US4995030A
Cited
US4912758A
Cited
US5062102A
Cited
US5084865A
Cited
US5195132A
Cited
US5195132B1
Cited
US5239542A
Cited
US5307405A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-08-03 | 2002-02-02 | 2002-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-08-03 | 2006-02-02 | 2006-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-08-03 | 2010-02-02 | 2010-08-04 | $7700.00 | Window Closed / Lapsed |