A comb generator based on a fast (74ACT series) digital IC.
The junkbox contained a 74ACT11000, but a 74AC(T)00, 74AC(T)02
or other NAND or NOR port should work as well.
The generator is a "plug-on" , for a square wave generator.
The 9 pin connector carries both power (8-12 V) and input signal.
The adapter on the left is used to connect a lab power supply and
the lab DDS generator.
