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Old March 20th 07, 11:32 PM posted to sci.electronics.design,rec.radio.amateur.homebrew
Anthony Fremont Anthony Fremont is offline
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First recorded activity by RadioBanter: Mar 2007
Posts: 34
Default LC Oscillator Questions

john jardine wrote:

The prettiest waveforms come from balanced oscillators. Distortion
then turns up as 3rd 5th 7th etc harmonics which are far less ugly
than the 2nd 3rd 4th 5th etc generated by the single ended types.
Balanced ALC is also easier and more effective.


The "conversation" that L1 and C3 sure looks nice on the scope. :-)

My own experience says that 'prettier' is better. Those oscillators
offering gross distorted outputs also seem to suffer badly in other
areas and gross distortion always causes problems further down the
line.


Procuring good quality is a classic black art, one aspect is to
allow the LC just an occasional vague glimpse of the maintaining
amplifier. Another is to cause limiting by use of an amp having a
gentle gain change (eg Fet v bipolar) and the other is ALC. (Or all
three together).


Well there sure isn't much talk about it out there. Material I find is
like, "here's a schematic, pick a coil and cap and your done. No one seems
to care what the result looks like. Seems like you can make a reasonably
decent wave _and_ still have the oscillator start reliably.

Failing that, there is always the cop-out of an output filter


Seems to be the way people like to do it. ;-)
john