This is part of my Frequency Standard System.
This board derives utility frequencies off the main 10MHz frequency signal. It has four 50Ω TTL outputs for: 5MHz, 1MHz, 1KHz and 1PPS. The 1PPS signal is driven by a 74HC123 monostable multivibrator from a 1 Hz signal that gets divided down using 74LS90 dividers.
