ANORDNUNG ZUR DECODIERUNG VON SIGNALEN.

摘要

Audio signals multiplexed with a 57 KHz AM subcarrier are applied to a circuit (2) comprising a band-pass filter, control circuit and subcarrier demodulator whose output is forwarded to area and message identification frequency filters and limiters (3, 4). The decoder (5) includes a microprocessor producing a reference signal of controllable frequency and phase from the constant-freqeuncy time base. A base and frequency comparator stage adjusts this reference signal in accordance with the received signal, producing an output if a correspondence is detected between the received signal and the reference w.r.t. phase and frequency. Area and message signals are processed without prior frequency selection.