Electrical audio signal processing systems and devices – One-way audio signal program distribution – Public address system
Patent
1981-03-05
1984-01-17
Rubinson, G. Z.
Electrical audio signal processing systems and devices
One-way audio signal program distribution
Public address system
179 84VF, 1791702, 324 77R, G10L 100
Patent
active
044267290
ABSTRACT:
Energy in a received signal is distinguished as being whole band energy or partial band energy by comparing an average value of the received signal to a modified magnitude value of the received signal. A signal representative of the comparison result is supplied to a filter including hysteresis for generating a signal to control representative of whether whole band or partial band energy is present. Hysteresis is provided in generation of the control signal by comparing the output amplitude of the filter to a first threshold value when the control signal is a first state and then comparing the filter output amplitude to a second lower threshold value when the control signal is a second state. When the modified magnitude value exceeds the average value, the received signal includes whole band energy, otherwise the received signal includes only partial band energy. In one example, this technique is employed in an echo canceler to enable updating an echo path estimate during intervals that the received signal includes whole band energy and to inhibit updating of the echo estimate being generating when the received signal includes only partial band energy.
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Bell Telephone Laboratories Incorporated
Myers Randall P.
Rubinson G. Z.
Stafford Thomas
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