[Paul] likes a precise oscillator. His recent video shows a crystal oscillator with a “watch crystal” and a CMOS counter, the CD4060. Using such a circuit can produce very stable frequencies and since the 32.768 kHz crystal is a power of 2, you get nice divisions out of the counter.
We’ve seen the same trick done with decade counters (like the 4518B) to divide by 10 instead of powers of two to make frequency standards. A 1 MHz crystal can easily generate 100 kHz, 10 kHz, etc.
[Paul] mentions the clock is a Schmitt trigger input (he said output, but he meant input) and so it can take a noisy input from an oscillator with no problem.
The board is commercial, but the circuit is simple enough. The 4000-series CMOS is nice because you can use it over a wide voltage range and you can bias it in a linear range for things like simple crystal oscillators. Just be aware that if you do want to use a CMOS gate as a linear device you want to look for unbuffered versions (UB suffix). In 1972 the 4000A series ICs appeared and were all unbuffered. However, there were a number of flaws. The “B” series fixed some of these flaws at the expense of increasing propagation delay. by buffering. Since some designs rely on the unbuffered behavior, certain parts remain unbuffered and have a “UB” suffix.