ACCESS_TONE_BURST

Published:2009/7/20 19:53:00 Author:Jessie | From:SeekIC

Generates 1-s tone burst at specified audio frequency such as 1800 Hz each time transmitter is energized, to pro-vide access to a desired repeater. Uses CMOS CD4001AE quad NOR gate, which is small enough so entire circuit can be fitted in micro-phone housing. Gates are connected as astable MVBR, with ON time of tone burst determined by R2C2 time constant, triggered by push-to talk switch (PTT). Large capacitor C3 powers MVBR during burst, with capacitor normally charged to 12 V through PTT circuit during receive. Supply voltage is taken through Prr relay in transmitter.-G. Hinkle, Tone-Burst Genera-tor for Repeater Accessing, Ham Radio, Sept, 1977, p 68-69.



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