Telecommunications Radioelectriques Et Telephoniques T.r.t.

Telecommunications Radioelectriques Et Telephoniques

Francoise Moliere

Gilbert M Ferrieu

Emmanuel Lefort

Jean-Yves Boisson

Thierry Langlais

Roger B Hamel

This arrangement has an input (10) for receiving the information to be encoded in the form of fixed words comprising a number of bits, a first transcoding member (20) for applying said variable word to 'n' outputs among n parallel outputs, a second transcoding member (22) for supplying from its output the indication of the length (n), and an accumulation member (30) for forming a first 'modulo N' accumulated information and a second 'modulo 2N' accumulated information, which are the result of operations performed on 'n'. A cyclic permutation circuit (32) supplies a permuted word which represents the permuted variable code word as a function of the first accumulated information, switching circuit (35) selectively transfers as a function of the second accumulated information the bits of the permuted word to a first and/or to a second register, and detection circuit (30,45) cooperates with the accumulation member for detecting the fill level of one of said registers to act on the transfer circuit so as to transfer the content of the filled register to the output.

Statistic coding arrangement for producing code words comprising a

An anti-Larsen circuit for a telephone station in which the listening channel comprises an automatic listening level control circuit, suitably of the type comprising a variable attenuator circuit, a pulse-width modulator and a threshold detector which supplies compression pulses. The transmission channel comprises a circuit for rendering the transmission channel operative or inoperative and also a control circuit. Actuation takes place above a sound-level threshold S.sub.1 and a de-activation below a sound-level threshold S.sub.2 which is smaller than S.sub.1.

Anti-larsen-effect arrangement in a telephone station equipped with a

This arrangement comprises a controllable attenuation circuit of the voice signal received, a pulse-duration modulator which produces pulses the duration of which is modulated by the voice signal supplied by the controllable attenuation circuit, an overshoot detection circuit which produces from the modulated pulses a compression pulse each time it is detected that the amplitude of the modulated voice signal reaches a certain threshold, the compression signal produced by the said overshoot detection circuit being applied in the attenuation circuit to an integrating circuit which produces the attenuation control signal. The amplifier of the loudspeaker receives the modulated signal.

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Paris, France

Francoise Moliere