REMOTE_FINE_TUNING

Published:2009/7/14 4:36:00 Author:May | From:SeekIC

Addition of voltage-variable capacitance diode to crystal feedback path provides capacitance range of 50 to 12 pF with tuning voltage range of 0-30 V. Diode supplements 2-60 pF trimmer capacitor that adjusts oscillator frequency with respect to control-voltage input. Inverting input of A1 connects to reference voltage VBB, which is available on pin of MC10116 and is center volt-age of output signal swing of amplifier. A2 is connected as Schmitt trigger to give high-speed rise and fall times. Frequency deviation on either side of center is function of crystal frequency and ranges from±50 to±300 PPM for crystals between 1 and 20 MHz.-B. Blood, Fine-Tune This Oscillator with Voltage, EDN Magazine, Aug. 5, 1978, p 74.



Reprinted Url Of This Article:
http://www.seekic.com/circuit_diagram/Control_Circuit/REMOTE_FINE_TUNING.html

Print this Page | Comments | Reading(3)