[Elecraft] SDR-IF and I/Q questions

[Richard Fjeld]

Thank you, John, for posting this. (see below)

I was going to comment that articles I have read say the software adjusts the phase of the 
I/Q signals in the soundcard to cancel images.  You have said it well.  WinRad & HDSDR, perhaps
others, are doing it well.  It seems to be a weak spot with PSDR-IF related software.

Thaks for sharing the Infrasonic related info.

Dick, n0ce

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The Infrasonic Quartet card (stereo, 192 kHz) comes with a small applet, 
called "FREEMIXER Panel," that works outside of the WIN sound management 
system. This helper app allows one to independently play with the levels 
(not the phase) of the incoming I/Q stream. I imagine other fast cards 
come the same way. Several of the SDR programs also have an "image 
killer" available. I am guessing when I say that this "image killer" 
works by adjusting the phase (time delay)...the ones I have used are 
offset-specific WRT the particular image that is removed.

John Ragle -- W1ZI
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