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Simple PLL FSK Modulator needed

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Jul 18, 2002
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pll fsk

Hi all:

I need a simple circuit to make an FSK modulator (with F0 = 400 kHz) with a lausy PLL like LM566 (from N@tional). The receiver is working great with LM 567: with any signal it demodulates, with noise, it demodulates even better, I yel to the board and demodulates too!
But I'm still looking for a good Modulator. Bandwith = The most I can get (like allways happens) but 20kHz will be great.

thanks to all in advance!!!!

simple pll

Exar makes FSK ICs. One is the XR205. They are based on the VCO in the PLL ICs.

Alternately, force a two level DC voltage onto the loop filter pin of the PLL IC you are going to use for tone generation. First put in the two tones you want to generate and measure the loop filter pin voltage at each of the two frequencies. Use these. The data sheet shows that two resistors and a current source are connected to this pin so you probably will not break anything by trying the above method.

565 fsk

try to see cypressmicro application note you can find good solution with pSoc devices


simple fsk modulator

I also want to know how to design fsk receiver

ne564 pll modulator

If you want to demodulate FSK signal, a PLL can do the job by observing the input voltage of VCO.

simple fsk modulator design

Other option is to use the NE564 PLL as FSK modulator ...
Example here:
**broken link removed**

fsk pll ic

i also need a simple fsk demodulator using lm 565

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