Wednesday, January 02, 2013

VFO wave

I decided to have a closer "look" on the 1972, 73 magazine VFO circuit from a previous post.

The circuit (minus the red part):

The setup:

 ..coil is from an old IF transformer and the tank cap was the first on hand...
turns out it oscillates at:


Now the output wave with "post processing" markers...:

 ...period is almost one division (10uS).
it's not a perfect sine even when "stretched":

 ...almost 8uS of period (4 divisions), that translates to 125Khz, close to the measured 137Khz (7.3uS), a normal error due to optical and timebase factor..

...will try other oscillator circuits in the future searching for the perfect wave....

Have a great 2013!

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