VOLTAGE_TUNED_WITH_10;1_FREQUENCY_RANGE

Published:2009/7/6 3:49:00 Author:May | From:SeekIC

Exar XR-S200 PLL IC is connected to generate basic periodic square or sawtooth waveform. Multiplier section, used as linear differential amplifier, converts diffetential sawtooth input waveform to triangle wave. 5K pot connected between pins 8 and 9 rounds peaks of triangle to give low-distortion sine wave with less than 2% total harmonic distortion. Output frequency can be swept or frequency-moduiated by applying proper analog control input.For linear frequency modulation with less than 10% deviation, modulation is applied between pins 23 and 24. For larger deviations, negativegoing sweep voltage Vs is applied to pin 18 as shown. Digital control input pins 15 and 16 can be used for FSK applications; if this is not desired, pins are disabled by connecting to ground through current-limiting resistor.- Phase-Locked Loop Data Book, Exar Integrated Systems, Sunnyvale, CA, 1978, p 9-16.



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