Telephonic communications – Echo cancellation or suppression – Using digital signal processing
Reexamination Certificate
2005-07-12
2009-06-30
Gauthier, Gerald (Department: 2614)
Telephonic communications
Echo cancellation or suppression
Using digital signal processing
C370S286000, C370S289000, C379S406070, C379S413010, C704S248000
Reexamination Certificate
active
07555117
ABSTRACT:
A path change is detected by multiplying the energy of a signal on the output of a summation circuit in one channel of a telephone by a constant to produce a product. The product is compared with the energy of a signal on the input of the summation circuit. A path change is indicated when the energy of the product exceeds the energy of a signal on the input of the summation circuit. The comparison is made in successive frames of an audio signal and a path change is indicated when the energy of a signal on the input of the summation circuit is exceeded in two or more successive frames.
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Story Franklyn H.
Suppappola Seth
Acoustic Technologies Inc.
Gauthier Gerald
Wille Paul F.
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