frequency detector

[grounded]

thanks
so it data sheet, Google and print PDF time.
like I said using the NE567 work fine just thinking it would be easy todoall with 12f629 but look a lot more than I thought
any search tips?
thanks as always

[fronkensteen]

thanks
so it data sheet, Google and print PDF time.
like I said using the NE567 work fine just thinking it would be easy todoall with 12f629 but look a lot more than I thought
any search tips?
thanks as always

You want just the 15.75Khz signal and you're trying to count just that 15.75Khz signal to detect the presence of a video signal.
One of the problems is the fact that there's a lot more going on than just that 15.75Khz signal, so you're probably counting a heck of a lot more than just that.

Maybe add a fairly tight bandpass filter in front of your input/amplifier and see what happens.
Mostly though I think I would put an o-scope on the input pin and see what you actually looking at.