--- In [email protected], "Janne Pulkkinen" <[EMAIL PROTECTED]> wrote:
>
> Is there any place where I could see the effect of image cancelation
> visually. It would be nice to see print-screen (Winrad, Sdradio,
> Powersrd etc.) from zero image rejection and second pic from full
> image rejection so I can be sure that I'm doin' it right :)
Janne,
nothing of more easy. I connected a signal generator to a QSD driving
the sound card. Then I started Winrad,
and captured the following two pictures. The first :
http://www.i2phd.com/images/image.gif
is what what you see when the unbalancing is total, here the image
response is even stronger than the true signal.
The second :
http://www.i2phd.com/images/noimage.gif
is what you see when the balancing is done at its best. The image
response cannot be seen anymore. Of course you
cannot maintain such a good rejection all over the band, for this you
need an automatic algorithm, not a manual
balancing. From my experience, sampling at 96 kHz, if you do an almost
perfect balancing in the middle of the upper
(or the lower) half, you can count on approx. 45 - 50 dB of rejection at
the band extremes.
This at least with my hardware.
73 Alberto I2PHD
