--- In [email protected], "D. J. Wang" <[EMAIL PROTECTED]> wrote: > > Hi everyone, > I am a little puzzle with this phenomenon when I run Winrad, may be someone or Alberto can help explain it. > My setup is pretty basic, a generic soundcard (running at 48KSPS) with a AD9951 DDS driving a SDR hardware design by YU1LM (74HC4053 + 74AC74). Reception is great with Alberto's software, however, I notice instead of getting the full 48KHz bandwidth I was getting only 24 KHz -i.e., right side of the spectrum is just a mirror image of the left side. Identical signal can be seen at both +F and -F position relative to center of the spectral window. I though using this I/Q detection you can differentiate positive from negative frequencies (relative to frequency zero), am I wrong? > Thanks! > > de D.J. /NM3R >
Hi D.J. I've had exactly the same problem, traced to faulty TL072 OpAmp. Also check panning slider on your LineIn recording mixer. I found mine in full right position, after much head scratching :). Simply connect some headphones to RX and check if you hear some noise on both ears. Worked for me. GL! Mario 9A4DE
