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.

In article ,
says...


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.



I guess that I used crystal too loose. Anyway the small processors and
clock circuits for them are very inexpensive.

Digikey has for sale crystal oscillators that can be programmed for most
any frequency for around 2 to 3 dollars. I have even ordered them
already programmed for about $ 4 each. I am sure in quanties of
thousnads from the manufactor they are very inexpensive.

On 3/22/19 12:25 PM, Ralph Mowery wrote:
I guess that I used crystal too loose. Anyway the small processors and
clock circuits for them are very inexpensive.

Digikey has for sale crystal oscillators that can be programmed for most
any frequency for around 2 to 3 dollars. I have even ordered them
already programmed for about $ 4 each. I am sure in quanties of
thousnads from the manufactor they are very inexpensive.

I have ordered those for a project.
Certainly cheaper than having crystals made for $18-20 each.


--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

In article ,
says...
Digikey has for sale crystal oscillators that can be programmed for most
any frequency for around 2 to 3 dollars. I have even ordered them
already programmed for about $ 4 each. I am sure in quanties of
thousnads from the manufactor they are very inexpensive.

I have ordered those for a project.
Certainly cheaper than having crystals made for $18-20 each.





$ 10 to 20 is inexpensive for a special made crystal now. I only know
of 2 places right now, Bomar that last report was $ 50 per crystal and
minimum of $ 100 for an order. Another in England that is I think about
$ 30 per crystal.

In article t,
Ralph Mowery wrote:

Digikey has for sale crystal oscillators that can be programmed for most
any frequency for around 2 to 3 dollars. I have even ordered them
already programmed for about $ 4 each. I am sure in quanties of
thousnads from the manufactor they are very inexpensive.

I have ordered those for a project.
Certainly cheaper than having crystals made for $18-20 each.

$ 10 to 20 is inexpensive for a special made crystal now. I only know
of 2 places right now, Bomar that last report was $ 50 per crystal and
minimum of $ 100 for an order. Another in England that is I think about
$ 30 per crystal.

Those programmable-frequency oscillators may have distinctly worse
phase-noise characteristics than a real crystal in a good oscillator
circuit. They may not necessarily be suitable for communications
projects or others that are sensitive to phase noise / jitter.

In article ,
says...

$ 10 to 20 is inexpensive for a special made crystal now. I only know
of 2 places right now, Bomar that last report was $ 50 per crystal and
minimum of $ 100 for an order. Another in England that is I think about
$ 30 per crystal.

Those programmable-frequency oscillators may have distinctly worse
phase-noise characteristics than a real crystal in a good oscillator
circuit. They may not necessarily be suitable for communications
projects or others that are sensitive to phase noise / jitter.





They are 'dirty' compaired to a crystal. I have played with a couple on
a spectrum analizer just to see.

Probably not very useful if a clean signal is desired, but fine if just
a close frequency is needed for things like a microprocessor clock.

On 3/22/19 1:25 PM, Ralph Mowery wrote:
In article ,
says...


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.



I guess that I used crystal too loose. Anyway the small processors and
clock circuits for them are very inexpensive.

Digikey has for sale crystal oscillators that can be programmed for most
any frequency for around 2 to 3 dollars. I have even ordered them
already programmed for about $ 4 each. I am sure in quanties of
thousnads from the manufactor they are very inexpensive.



If the processor itself is timed from a crystal many uPs give the option
of scaling down the system clock via a hardware divider to generate a
reference clock for whatever purpose u need