[Elecraft] K3EXREF question

[Lyle Johnson]

Almost.

The TCXO has no control input and is not tuned; it is only measured.

The measurement information is passed to the radio's MCU which then uses 
the data to determine the correct value to command the synthesizer(s), 
drive the REF CAL display, and so forth.

73,

Lyle KK7P

> The K3EXREF circuit is essentially a AFC (sort of) where a highly 
> accurate 10-MHz reference is used to measure the frequency of the TCXO 
> and send a frequency correction "word" to control the TCXO so that the 
> error from 49.380 MHz is removed...