Phase-sensitive filter for receiver phase regulation - ensures receiver only evaluates received pulses occurring at correct time intervals

摘要

The phase-sensitive filter is used in a reception circuit for position location of a flying object incorporating a transmitter. The pulse period of the latter is used to obtain a time window in which the transmitter signal must appear. A clock generator (7) controls a preset counter (5) receiving an initial count value at the beginning of each transmitter signal period from a read-only memory (4). The counter (5) frees a shift register (6) at the beginning of the time window and blocks it at the end of the time window, the shift register (6) obtaining the filter input in response to each clock generator pulse. The output of the shift register (6) is coupled to a priority device (2) providing the highest priority for the centre of the time window, coupled in turn to the addressing circuit (3) of the read-only memory (4).