Some Si570 Circuits

The Si570 is a combined silicon oscillator, that has come to fame in amateur radio circles through its adoption in the SoftRock series of SDRs (or should it really be SDxs)


Silicon oscillators have the property that they are stable, but cannot be manufactures to a precise frequency in the way that quartz can. The Si570 however has an integral frequency synthesizer and so in a tiny package provides oscillator with a computer controlled output frequency.

G4EOP has several interesting pages on the Si570 including some PIC code.
http://g4oep.110mb.com/channels/channels.htm