Distributed VAD control system for telephone
First Claim
1. In a telephone including noise reduction circuitry having a plurality of sub-band filters in at least one channel, the improvement comprising:
- a plurality of voice activity detectors coupled one to each sub-band filter.
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Accused Products
Abstract
A telephone includes a transmit channel and a receive channel, each including a bank of sub-band filters having a VAD coupled one to each sub-band filter. Each VAD measures the spectral energy in a sub-band, compares the spectral energy to a first threshold, and produces an output signal representative of whether or not the first threshold is exceeded. The voice activity detector also includes a threshold circuit for calculating a dynamically adjustable noise threshold based upon averaged measured spectral energy. A wide band or system VAD monitors echo canceling circuitry to detect voice activity and double talk.
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Citations
19 Claims
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1. In a telephone including noise reduction circuitry having a plurality of sub-band filters in at least one channel, the improvement comprising:
a plurality of voice activity detectors coupled one to each sub-band filter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A telephone comprising:
a signal processing circuit, including an audio processing circuit, including an echo canceling and noise reduction circuit, including a first circuit for calculating spectral energy; and a comparator for comparing the spectral energy to a first threshold and producing an output signal indicative of whether or not the first threshold is exceeded; an averaging circuit coupled to said first circuit and to said comparator, said averaging circuit calculating said first threshold. - View Dependent Claims (12, 13, 14)
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15. In a telephone including an audio frequency circuit having a transmit channel and a receive channel, an echo canceling circuit and a noise reduction circuit coupled to the channels, and wherein at least one channel includes a filter bank for dividing the channel into a plurality of sub-bands, the improvement comprising:
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a plurality of voice activity detectors coupled one to each sub-band filter; and a broad band voice activity detector coupled to said echo canceling circuit. - View Dependent Claims (16, 17, 18, 19)
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Specification