CRYSTAIVFO_SYNC_GENERATOR

Published:2009/7/15 2:52:00 Author:Jessie | From:SeekIC

With crystal, can be used as system sync generator or as drive for staircase generators, custom pattern generators, and special TV test equipment. When VFO-controlled, circuit provides variable-frequency sync needed for determining pull-in range of sweep oscillators in TV sets and VTR decks. Clock-pulse section uses Q1 and Q2 as 1.00800-MHz Butler oscillator. On VFO operation, oscillator frequency can be varied ±3.5% from mean. Sine-wave output of Q2 is converted to square wave by Q3 for application to clock input of Hughes HSUB0525 sync generator. Each output of sync generator feeds one of inverters in 7404, providing 3.3 V P-P signal into 75-ohm load for each output.-M. J. Salvati, VFO Adds Versatility to TV Sync Generator, EDN Magazine, May 20, 1974, p 70 and 72.



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