Thomson-csf Telephone

Du Phan Tich

Andre Chataignon

Jean-Pierre Poirier

The telephone station has a first attenuator inserted in a transmission channel, and a second attenuator inserted in a reception channel. Each attenuator has a variable impedance mounted in shunt on the corresponding channel. A circuit controls the attenuators as a function of the relative levels of signals collected respectively from the transmission and reception channels. A bridge circuit introduces a difference between the levels of the signals collected respectively from the two channels. The bridge circuit includes a resistor bridge formed by two fixed resistors inserted in each channel upstream of the attenuator which is associated with said channel, and by a variable impedance which constitutes the attenuator. The common node of the two fixed resistors is the point of collection of the signal from each channel.

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Colombes, France

Du Phan Tich