Dave:

I have seen designs used which use a "white noise generator" at their osc.

Simply filter the freq you want from it and off you go...

John

"Dave Platt" wrote in message
...
In article nH6Ge.22103$HV1.10801@fed1read07,
Caveat Lector wrote:

Just out of curousity -- what modern Ham gear uses a Colpitts oscillator or
a swinging choke ??

I believe that a goodly percentage of fixed-frequency quartz crystal
oscillators use a Colpitts configuration in their feedback circuitry.
Pierce topologies are likely used, as well.

The L in such oscillators is the motional inductance of the crystal,
rather than the inductance of a wire-wound inductor, but the principle
is still the same.

Then why ask these questions on a 2005 Ham test ??

Because the circuits are still relevant, to either modern ham gear, or
to the older gear that many hams refurbish and use, or to both.

Maybe ask about a VCO or a crowbar circuit ??

VCOs require some form of positive feedback in order to oscillate.
This can be in a Colpitts configuration just as well as in any other.

Questions about a crowbar would certainly be relevant as well.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!