Thomson-csf

Thompson-csf

Sylvain Fontanes

Roger Benoit-Gonin

Jean L Berger

Jean-Luc Berger

Jean-Edgar Picquendar

Jean E Picquendar

Roger B Gonin

Claude Michaud

An analog device for reading a quantity of electric charge, for example, in a transversal charge transfer filter. The device includes a capacitor and two MOS transistors which are connected in series to the point in the filter where the charge is to be read. The capacitor is connected to the common point of the two transistors which are controlled in phase opposition to insure charging of the capacitor. The capacitor maintains a potential at the charge reading point constant. Any variation in the quantity of charge under an electrode is converted into a variation of potential at the common point and this forms the read signal which is detected by means of a third MOS transistor.

Device for reading a quantity of electric charge

As all the weighting coefficients of the filter are positive, a weighted charge quantity is collected by a line beneath one of the elementary electrodes of each weighting electrode. A charge reading device is coupled to the line and supplies an electrical signal which is transmitted to the negative input of a differential amplifier, which receives the sampled input voltage of the filter at its positive input. The electrical output signal of the filter is taken, under low impedance, at the output of the differential amplifier, said signal being reinjected at the input of the filter by the injecting means.

Charge transfer recursive filter

An analog-digital coder applicable for the coding of analog information in accordance with non-linear functions of compression such as the laws A and .mu. as set forth in the standards of the CCITT (International Telegraph and Telephone Consultative Committee). For non-linear coding the analog information is applied to an analog switch whose output signals are applied to an adder which also receives the output voltage of an amplifier. The output voltage of the adder is applied to a multiplier-analog memory which comprises a charge transfer device. Their output is coupled to the input of the amplifier. A comparator compares the output voltage of the multiplier-memory with a given voltage and controls a logic switching circuit which generates the coded output signal.

Analog-digital coder comprising a charge transfer device

An input stage for a transversal charge transfer filter, which suppresses parasitic image frequencies. It comprises two parallel channels to which the input signal is applied simultaneously. Sampling of the signal is performed in each channel with a periodicity Te, and a relative phase-shift of Te/2. The two samples are then added in order to eliminate components having periodicities in the neighborhood of Te.

Input stage for a CTD low-pass filter

The holding integrator of the arrangement, which integrator is to integrate the signal to be encoded during time intervals T.sub.1 = pT separated by time intervals T.sub.2 = qT in the course of which the integrated value is to be memorized for comparison with one or two ramp signals, comprises a charge transfer device with (p+q) stages receiving advance signals having a period T. The signal to be encoded is applied to the injection circuit of the charge transfer device during the intervals T.sub.1 while a zero voltage is applied thereto during the intervals T.sub.2.

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Paris, France

Sylvain Fontanes