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On Wed, 11 May 2005, Chris Wilkson wrote:
> Despite all of this, the delay (pin 10) input is supposed to be a DC
> voltage. If you actually measure it, it will look like a DC voltage
> with some high frequency (~50 MHz per above) noise riding on it.
> Plus any noise that comes from VCC.
I don't think the DC component is the important part. If you look
at the schematic, the delay line is connected to the gates of several
transistors in the delay chain.
I think the frequency of the AC component is the important bit.
Adjusting the pot on the board changes the time constant of a simple RC
oscillator which generates the delay signal. Each time the delay line
gets high enough to trigger those transistors, the colorburst frequency
is shifted down the delay chain.
I really need a scope.
- --
adam@xxxxxxxxxxxxxxxx http://cuddlepuddle.org/~adam
KG6GZR http://cuddlepuddle.org/~adam/resume.html
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