MOTION DETECTOR SIGNAL PROCESSING CIRCUIT

摘要

A motion detector circuit comprising a transmitter for transmitting a detection signal field in an area to be protected. A receiver is provided for sensing the signal field. A signal squaring circuit is connected to the receiver for producing control pulses in response to AC signals caused by movement of an object in said field. A square wave generator produces alarm pulses corresponding to the control pulses. An interval timer circuit and an accumulator circuit is connected to an output of the generator. The interval timer circuit enables the accumulator for a predetermined time interval starting from the presence of a first alarm pulse at the output of the generator. The accumulator is connected to an alarm which is activated by operation of the accumulator when a preset threshold value is exceeded within the predetermined time interval that is enable by the timer circuit.