Re: Amateur question pools and answers...

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" <hamop@xxxxxxxxxxx> wrote in message
news:9ZGdnVSjCrEI4HffRVn-1A@xxxxxxxxxxxxxx
> 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.
>
>


.

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