Ham op:

Just drew the circuit of a xtal in the feedback of a high precision op amp
circuit... hmmm, could be colpitts--but can't see the resemblance...

Just drew the circuit of an xtal chucked in the feedback line of a set of logic
gates... hmmm, that could be colpitts too, but again, can't see the
resemblance...

John

"Ham op" wrote in message
...
John Smith wrote:

Wes:

Those osc are a thing of the past...

Bring a junk am broadcast radio near your computer, you will hear literal
dozens (well, a bunch anyway!) of osc's freqs going on there, probably not
one being generated by a colpitts, hartley or pierce osc circuit...
And, with the proper processing, all those waves could be a sine...

John

Each of those oscillators use a crystal for frequency and stability!
Each of those oscillators uses positive feedback so that it oscillates.
Draw the equivalent circuit of those oscillators and you will find the
COLPITTS circuit !!!!

I wonder if you are confusing the Coplitts/Hartley topography with the old
VFO which were/are variable tuned [Colpitts/Hartley] oscillators.

Every digital frequency synthesizer uses a Colpitts oscillator as the
reference oscillator, at a fixed frequency, and the variable oscillator is
digitally phase locked to it.

The basic Physics and governing laws for oscillators has not changed.