The even newer structure (that I named after the culprit) works with a very different frequency, but 3600Hz is not a total stranger: it's a divisor of frequencies that have been used in other projects.

I can already test the electrical characteristics with the 32768Hz generator and make sure the edges are clean with the 'scope. But the Rb source is broken and I need something to (roughly) calibrate the 18KHz resonator.

By a nice coincidence, 18432=1024×18. I just need to find a 18432KHz canned oscillator and feed the signal to a 74HC4040. I have a huge stock of 4040 (from the #Discrete YASEP ebay binge) but I used all my canned oscs in PIC circuits that need to speak serial.

Another happy coincidence : 3600×1024=3.6864MHz, which I have also used (in #Discrete YASEP too). And it doesn't need a ÷5 predivider.