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> > I am looking for a minimal hardware circuit to generate a 125 kHz
> > sinusoidal wave to be fed into the power stage that is in turn feeding
> > an antenna. The wave is used to generate a carrier frequency for an
> > RFID application.
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> > I was thinking of using this
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> ] crystal in a Pierce Oscillator configuration. However I am not sure
> > if this crystal will work in that configuration. Also, I can't seem to
> > figure out what the output would look like. Would it be a square wave
> > or a sinusoidal? I came across a diagram that pictured a sinusoidal at
> > the inverter input and a square wave at the output for the Pierce
> > configuration. Is that correct?
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> > I would greatly appreciate any pointers on this.
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> > Thank you!
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> Try a Phase-Shift oscillator. I use them easily for
> audio frequencies, not sure I've gone up to 125khz
> though.
> Ken- Hide quoted text -
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The 125khz crystal is the most difficuot item.
Use bipolar autobiassed amplifier for crystal 100KHZ or so . collector load of 100kohm. 1M from base to collector. capacitors. of 470pf from collector to ground and base to ground crystal from collector to base.Oscillation will build till it clips ( during clipped part of the cycle gain is zero.) =2E Detect signal at the collector with high impedance and reduce the supply to the collector resistor when a suitable non clippng amplitude is reached. Should be able to limit harmonics to -30db when a simple lpf will get you to -40db.