On Thursday, 21 March 2019 14:39:57 UTC, Ralph Mowery wrote:
In article ,
tabbypurr says...

Hello, and I already addressed your other post. I think a crystal is
probably likely. You said it was unlikely but don't offer sensible
reason(s) why (e.g. temperature and vibration stability, etc)

cost, as I said.




The cost of small microprocessors and crystals are almost nothing. Look
at the Arduino processor boards. They can be bought from China for
about 2 ot 3 dollars. They are powerful enough to run the inverter part
of the inverter.

No sensible manufacturer is going to use a crystal` where they can use a ceramic resonator or a silicon oscillator built into the chip. And no sensible mfr is going to pay for a crystal plus a divide by massive number circuit when they can use a low frequency oscillator. If you can't see why there's nothing further for us to discuss.