General crystal/PLL question

The color burst signal(burst of 3.58 MHz was applied to the crystal.

(Those cans were HUGE

No nothing special.

Not sure what you mean by "sync signal". Yes it will work if you pulse it with a 3.58 MHz bust., The crystal will "ring" in phase with the applied burst.

Mark

Hi Mark, Thanks for the reply. I was typing out loud that day. I remembered later that I actually have the books from the 50s about color TV. Turns out the crystals *were* specially designed to have a lower Q than typical crystals, and that they were used in a ringing circuit, not a true oscillator AFAIK. They just whapped it with the colorburst, and then sent the decaying signal through a limiter, and this was enough to generate the color reference.

As for the sync, I was referring to a horizontal sync pulse from a computer. Let's say the computer uses a 16MHz clock and I want to re-create this pixel clock only having access to the HSYNC. Typically a PLL system will try to lock a VCO with feedback from a divider, suitably programmed with the division ratio of 1016 in this case.

I just wanted to avoid using the counter altogether if I could somehow just use the rising edge of the sync and see if I have a zero-crossing on my LO. Turns out this is a lot more work that just using a regular video genlock PLL.

(Those cans were HUGE

So sorry sirs, the horizontal sync pulse and "back porch", where the color burst is, was used a "gated" phase comparison in an otherwise standard phase locked loop, which used a sample and hold and a reactance tube to tune the "VCXO". (1960's) An early sampling control system if you will.