Here's two web pages that discusses using variable capacitance to produce gain at f/2 as part of a larger discussion of varactor diodes and parametric amplifiers.. These pages specifically discusses
Hi Jeff, I've seen parametric as amplifiers in giant parabola dish at space ground stations already in the seventies, so not really new for me although I didn't really deal with any, my job was with
I read these pages and couldn't find a reference to the f/2 discussion. It seemed to discuss injecting energy into a resonant cavity using a charge pump running at twice the cavity frequengy and also
Don't be too hard on me Jeff - I was only passing on my best recollection of an article I read that offered an explanation for things I'd seen in practice. Also, I think I wrote ...**maybe** even noi
I've been in Sweden (again!) last week, so have only followed this from afar....... Frequency dividers using 'linear' parts are quite old. The simplest of them uses an amplifier at the divided freque
applied to Hi Peter, although a fraction of a fundamentel carrier can be somehow produced, this wasn't the original topic, a sub harmonic is something that doesn't exist. By nature, phisically and e
The reference to gain at f/2 is there...near the top of the second reference... For proper operation, the capacitance must be decreased when the input voltage is maximum and increased when the input
Here's a message received from a guy I knew at university aeons ago. He reads the archives but is not a subscriber. I'm not sending it because it carries any personal baggage for me but because it's
Hi Jeff. Thanks for you mail. I think the topic is drifting where one fellow had a problem with a spur on his amp at 1.5X the fundamental. The discussion the came to suggestions that the AMP was crea
? The presumably highly-qualified and very experienced engineers at a well-respected West-coast amplifier manufacturer have managed to design three amplifiers which use 4.75 - 5.25 V rated filament
Comments embedded below... And yes, this is a very interesting topic. Of course the real problem will probably turn out completely unrelated. on his sub-harmonic re-inforcing I still think something
It is especially interesting now that Dave says he duplicated the problem with diodes. I have never been able to generate a submultiple of a signal with an form of non-linear system, including satur
You're quite correct that non-linearities do not directly generate anything other than integer harmonics 2f, 3f, etc. But it still possible to generate sub-harmonics with a non-linear reactance, a pa
Check out http://www.k1ttt.net/subharmonics/subharmonic.htm for the circuit I used and picture of scope traces. It is bigger than I wanted so it may take a while to download. As for the use of 'subha