Hi Richard, Some answers, below. --matt
On 11/5/2016 9:38 AM, Richard Lamont wrote:
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?
The KIO3B uses a codec (digital on its USB side, analog one the audio side (line in/out). The codec's USB D+/- nets are connected to a USB hub.
2. It seems to support sampling rates of 32000, 44100 and 48000 Hz, but not higher or lower values. Is this correct?
These are the sample rates the codec supports. Yes.
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?
The clock is an XO: 12 MHz, +/- 100 ppm as rated. The XO's output is buffered and feeds the codec.
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?
You can find a copy of the data sheet here: http://www.digikey.com/product-search/en?keywords=PCM2901E%2F2K
73, matt W6NIA
TIA.
-- Always store beer in a dark place. - R. Heinlein Matt Zilmer, W6NIA [Shiraz] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
