U.S. Philips Corporation

Lucent Technologies Inc.

Gerard Pouzoullic

Robert Boudault

The power supply modules, together feeding a load (between the terminals 13 and 12) with the voltage V.sub.0, comprise blocking diodes D.sub.1 (or D.sub.2). A feedback loop controls the output voltage (controller 14 and comparator 15 which receives V.sub.ref1 (or V.sub.ref2)). Two output voltage terminals are used for locking, on the two electrodes of D.sub.1, the voltages V.sub.1 and V.sub.0 (or D.sub.2 with the voltage V.sub.2 and V.sub.0), and are connected to inputs of output voltage selection means (31) which are suitable to supply either the voltage kV.sub.0 (k.ltoreq.1) when D.sub.1 (or D.sub.2) is conductive, or the voltage kV.sub.1 =V.sub.ref1 (or kV.sub.2 =V.sub.ref2) when D.sub.1 (or D.sub.2) is blocked.

System for operating a plurality of power supply modules in parallel

A frequency demodulator including an 'exclusive-OR' circuit receiving two square-wave signals having a frequency corresponding to a frequency-modulated signal, and a delay circuit for delaying one of the square-wave signals before application to the 'exclusive-OR' circuit, by a delay varying versus frequency in such a way that the absolute value of the phase difference between the square-wave signals varies at most from 0.degree. to 180.degree. inversely with respect to changes in frequency. The output signal of the demodulator is supplied by a low-pass filter connected to the output of the 'exclusive-OR' circuit.

Frequency demodulator employing a circuit having a delay varying with

The frequency shift modulator comprises an operational amplifier connected so as to form an integrating circuit and followed by a bistable circuit having trigger hysteresis for producing a two-level voltage which is applied to one end of a first resistor whose other end is coupled to an input of the operational amplifier. Logic means are provided for applying a voltage equal or complementary to the said two-level voltage, depending upon the level of the data signal, to one end of a second resistor whose other end is joined with the said other end of the first resistor. Further logic means are provided for applying a voltage equal or complementary to the said two-level voltage, depending on whether the desired modulated signal has either the one or the other central frequency, to one end of a third resistor whose other end is joined with the joined ends of the first and second resistors. Finally, a common resistor is connected between the joined ends of the three above-mentioned resistors and the input of the operational amplifier.

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Gif Sur Yvette, France

Gerard Pouzoullic