Greetings, I have two signals, I need a way of testing whether they go above certain threshold voltages for a period of 0.5 seconds. This must be non programmable. I am a bit stumped o how to do it. I thought of having these signals go into an AND gate and then have that AND gate feed into a timing circuit somehow, but I don't really know how I would design such a timing circuit. The 555 timer will not work because I need to start the timer, then have it wait, then send a logical high if and when the two signals have been above their threshold voltages.