QS1-R vs SDR-14 vs Perseus -- Direct Sampling HF Receivers
andre kesteloot
andre.kesteloot at verizon.net
Mon Jan 25 08:51:57 CST 2010
Mike O'Dell wrote:
> speaking of oscillators, i remember in the dim past,
> a member of this august group (Andre? Hal? Dave?) came
> up with a circuit from a wizard at COMSAT for a
> *synchronized oscillator*. I vaguely remember it being
> like a cascode pair with the upper transistor basically
> forming a pretty ordinary crystal oscillator and the
> lower unit getting the sync drive. the advantage was
> that it could multiply the sync drive by a remarkably
> large number without the phase noise of a PLL multiplier.
> (I think this came up back during the DSSS experiments.)
>
> is that schematic around anywhere?
Mike,
Indeed, I used it in my Spread Spectrum Transmitter that appeared in QST
for May 1989 and in the ARRL Spread-Spectrum Sourcebook p 8:52
I also used it in a clock recovery circuit. See pp. 8:55-57
Finally, James Vincent G1PVZ, having read the QST article, managed to
implement the circuit with a IC: In appears in the Sp Sp Sourcebook on
p7-12
(Aaah, the good old days... :-)
73
André
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