[Elecraft] K3S USB audio questions

[Richard Lamont]

A few questions about the K3S internal audio interface:

1. Is the internal connection between the USB audio interface and the
2nd IF analogue or digital? If digital, how is the sample rate
conversion implemented?

2. It seems to support sampling rates of 32000, 44100 and 48000 Hz, but
not higher or lower values. Is this correct?

3. What determines the clock frequency for this sampling? Is it a
free-running crystal? If so, what is its frequency tolerance? Or is it
locked to the main TXCO and/or external 10 MHz reference?

4. When listening to SSB audio at S9+, with slow AGC, the output level
via this interface seems to be -22 dBFS true peak. Why is it throwing
away three bits of resolution? Or is this amount of headroom
necessary/useful?

TIA.

-- 
Richard Lamont G4DYA
<richard at lamont.me.uk>