I am building a circuit that uses a 4 MHz reference carrier. The used ICs are basically XOR 7486 and NOT 7404, CD4013 flip-flop, etc.
I have a function generator which is capable of providing up to 5 MHz. I tried to use it but I have a hard time getting the circuit to work.
When adjusting the amplitude to be a ±5 V square wave the ICs don’t seem to sense the input. I tried using the CMOS TTL output, but for some reason it’s stuck at 15 V peak (or is it designed to be? I don’t know) and the ICs work, but I am afraid that’s too high an input voltage.
Another issue I faced is that when I drive several ICs (say two) using the same clock from the function generator the ICs do not output as intended; it’s like there’s some loading effect which diminishes the function generator signal.
I tried searching data sheets for the used ICs but honestly I am at loss.
Below are pictures of the function generator, circuit, and schematics: