Serial data stream decoding pref. for personal alarm systems - involves checks on durations and logic values of pauses before and after reception of preamble binary sequence.

摘要

The method involves checking a received data stream for presence of a pause of specific duration, after which a specified length of e.g. 12 binary 1's corresp. to a complete preamble is monitored and its bit duration determined. A second pause precedes the data stream proper comprising 16 bits, whose sum is evaluated. The timing circuits (ZK1-ZK5) and comparison logic (KS) determine whether a reaction circuit (RS) or an error reaction circuit (RF) with an optical indication is to be activated. USE/ADVANTAGE - Data messages of any content can be recorded and decoded without any reception of synchronisation word from their source. Needs no precise frequency regulation.