Radio pager tone alarm circuit for generating variable duty ratio pulses modulated with a unique alert tone pattern.

摘要

A POCSAG compatible pager where the output of comparator (17) is a square waveform of fixed pulse repetition frequency and increasing in steps mark/space ratio. The POCSAG alert tone modulates in an ON/OFF fashion the output of comparator (17) and this results in a sound level that escalates every 6 seconds. <IMAGE>