Dave:
What is it that you "almost don't believe" ?
That it is this good? Or that it is this bad?
Remember that the sound card has a sampling clock, that also contributes
to any errors.
If it is a regular computer sound card, then it is using the same $0.33
crystal reference as the
rest of the computer.
--- Graham / KE9H
==
On 12/7/2013 2:24 PM, quartz55 wrote:
I've been testing my soundcard measurement capability with Speclab, so I hooked
my LPRO Rb to lock my Moto Service Monitor, fed the 1K audio out into the sound
card and I measured the freq over about a half hour. I got a spread of about
107uHz. I've tried a few other things through my TS2000 using a 1500Hz tone
from the USB and I can see when the fan goes on and off although I have the RX
main osc locked to the GPSDO with the XRef from VK3HZ. I can only assume the
drifting in the RX is due to the DSP processing crystal drifting with temp. I
get about 13mh drift on that. Anyhow, here's a shot of the 1000Hz directly
into the soundcard with Speclab.
http://i251.photobucket.com/albums/gg287/DogTi/time/1k30m_zpsc4173981.jpg I
almost don't believe it, does anyone else?
Dave
N3DT
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