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US 5,633,939 AGranted
Compander circuit
AssigneeFujitsu Limited
InventorsKazuhiro Kitani, Yuji Segawa, Kunihiko Gotoh
Life of this patent
Estimating the term…
Abstract
A compander circuit includes first and second volume controllers, a comparator, a counter and a control part. The comparator compares a compared voltage with a rectified and smoothed signal of an input signal of the compander circuit or an output signal of the first volume controller receiving the input signal, the compared voltage being an output signal of the second volume controller. The counter executes a count operation on an output signal of the comparator in synchronism with a clock signal and controls gains of the first and second volume controllers on the basis of a counter value of the counter. The control part controls a frequency of the clock signal applied to the counter by a predetermined control signal.
Claims30
A compander circuit comprising:
- first and second volume controllers;
- a comparator which compares a compared voltage with a rectified and smoothed signal of an input signal of the compander circuit or an output signal of the first volume controller receiving the input signal, the compared voltage being an output signal of the second volume controller;
- a counter which executes a count operation on an output signal of the comparator in synchronism with a first clock signal and controls gains of the first and second volume controllers on the basis of a counter value of the counter;
- and
- means for variably controlling a frequency of the first clock signal applied to the counter by a predetermined control signal.
2 more elements
A compander circuit comprising:
- first and second volume controllers, the second volume controllers having a plurality of different input/output characteristics;
- a comparator which compares a compared voltage with a rectified and smoothed signal of an input signal of the compander circuit or an output signal of the first volume controller receiving the input signal, the compared voltage being an output signal of the second volume controller;
- a counter which executes a count operation on an output signal of the comparator in synchronism with a clock signal and controls gains of the first and second volume controllers on the basis of a counter value of the counter;
- and
- selecting means for selecting one of the plurality of different input/output characteristics according to a predetermined variable control signal, the compared voltage being based on said one of the plurality of different input/output characteristics.
2 more elements
A compander circuit comprising:
- first and second volume controllers;
- a comparator which compares a compared voltage with a rectified and smoothed signal of an input signal of the compander circuit or an output signal of the first volume controller receiving the input signal, the compared voltage being an output signal of the second volume controller;
- a first counter which executes a count operation on an output signal of the comparator in synchronism with a variable clock signal and controls gains of the first and second volume controllers on the basis of a counter value of the first counter;
- and
- means for supplying the clock signal to the first counter only when the input signal continues to be at a predetermined level for a predetermined term.
2 more elements
A communications device comprising:
- a transmit system;
- and
- a receive system,
- the transmit system and the receive system respectively having compander circuits,
- each of the transmit system and the receive system separately comprising:
- first and second volume controllers;
- a comparator which compares a compared voltage with a rectified and smoothed signal of an input signal of the compander circuit or an output signal of the first volume controller receiving the input signal, the compared voltage being an output signal of the second volume controller;
- a counter which executes a count operation on an output signal of the comparator in synchronism with a clock signal and controls gains of the first and second volume controllers on the basis of a counter value of the counter;
- and
- means for controlling a frequency of the clock signal applied to the counter by a predetermined variable control signal.
7 more elements
A communications device comprising:
- a transmit system;
- and
- a receive system,
- the transmit system having a compander circuit comprising:
- first and second volume controllers, the second volume controllers having a plurality of different input/output characteristics;
- a comparator which compares a compared voltage with a rectified and smoothed signal of an input signal of the compander circuit or an output signal of the first volume controller receiving the input signal, the compared voltage being an output signal of the second volume controller;
- a counter which executes a count operation on an output signal of the comparator in synchronism with a variable clock signal and controls gains of the first and second volume controllers on the basis of a counter value of the counter;
- and
- selecting means for selecting one of the plurality of different input/output characteristics according to a predetermined control signal, the compared voltage being based on said one of the plurality of different input/output characteristics,
- the compander circuit having both a compressor characteristic and an expander characteristic.
7 more elements
Dependencies are inferred from the claim text.