Re: Si5351 Programming Flowchart

Jerry Gaffke

Yup, not much point in getting too carried away in creating a VFO for the Bitx40.
Initial accuracy of the si5351bx routines can be calibrated to be quite good by adjusting si5351bx_vcoa
But a slight change in temperature and the 25mhz reference will drift a few hz,
so stability will be an issue

If an application comes up where greater stability is required,
the 25mhz (or 27mhz) reference could come from an ocxo or tcxo, or be GPS disciplined,
or perhaps you constantly adjust a knob for zero-beat with a known accurate radio station such as wwv.

Jerry, KE7ER

On Mon, Feb 12, 2018 at 12:56 pm, Pavel Milanes Costa wrote:
El 12/02/18 a las 15:35, Jerry Gaffke via Groups.Io escribió:
Calculations within the si5351bx routines are much better than than 1ppm accurate, perhaps more like 0.01ppm.
As I recall, the math was accurate within 0.2hz when doing calculations for a high side vfo on the Bitx40 of 19mhz.
If the math/hardware has a better accuracy than the Xtal itself then you have at the output just the stability of the Xtal... right?

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