U.S. Philips Corporation

Johannes P Inghels

Johannes P Bahlmann

Pieter G Van Leeuwen

Christian H Baeten

Eduard Van Loo

A circuit for detecting pulses in an electric input signal, which pulses are superposed on a specific reference level (U.sub.ref), has an input terminal for receiving the electric input signal, at least a first and a second comparator device, switching means (S.sub.1), an output terminal and control signal generator means. The control signal generator means supply a control signal to the switching means (S1) to control the position of the switching means. The input terminal (1) is coupled to a first input of the comparator devices, whose outputs are coupled to a terminal (c and a respectively) of the switching means (S.sub.1). The output terminal (b) of the switching means is coupled to the output terminal. The first comparator device transfers only pulses whose relative amplitude in relation to the reference level exceeds a first value (U.sub.D1). The second comparator device transfers only pulses whose relative amplitude in relation to the reference level exceeds a second value (U.sub.D2). When input terminal receives N1 consecutive pulses whose amplitude relative to the reference level exceeds a specific (third) value (U.sub.D3) the switching means (S.sub.1) have been/are set to position c-b in such a manner that the first comparator is coupled to the output terminal. When subsequently N2 consecutive pulses are counted whose relative amplitude lies between a fourth and a fifth value (U.sub.D4 and U.sub.D5 respectively), such that U.sup.D5 &lt;U.sub.D4 &lt;U.sub.D3, the switching means (S.sub.1) have been/are set to position a-b in such a manner that the second comparator device is coupled to the output terminal. N1 and N2 are integers larger than or equal to 1.

Circuit for detecting pulses, and video recorder comprising the circuit

A receiver for use in a remote control system in which clock pulse-modulated information pulses are transmitted in a wireless mode to the receiver. The receiver is intended for use in hearing aids energized with supply voltages of approximately 1 V. The receiver includes a receiving device (1) for the conversion of the wirelessly transmitted information pulses into an electric signal and a cascade arrangement of first and second selective amplifier circuits (2) and (4), each of which have their highest gain factor at a frequency which is approximately equal to the frequency of the clock pulses. This cascade arrangement is connected to the output of the receiver device and supplies a first output signal to a mean value detector (5) which produces a rough version of the information pulses, which in turn are shaped in a pulse shaper (6).

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Eindhoven, Netherlands

Johannes P Inghels