> Count me as interested, and actually wondering why your diff-amp solution > wasn't the default? I wonder what the cost differential between the AD8132 > and the transformer used?
Actually, the differential amps are _cheaper_ than the transformers. I went with the transformers because they allow for very high IF frequencies -- the ADCs are spec'ed to 400 MHz, and I have done direct sampling as high as 1.2 GHz (with about 15-20 dB of loss). The differential amps don't perform well past 70 MHz or so. Even under 70 MHz, you'll get cleaner signals with the transformers, since they have no distortion or noise. > Speaking of, what is the usable low-frequency cutoff for those transformers > according to spec? I think they have a 3dB cutoff of around 100 kHz or so. If you need a lower cutoff you can switch them out for other Minicircuits transformers which have cutoffs as low as 10 kHz (like the T1-1T), at the expense of a lower frequency response on the high end. Most should be pin compatible. Matt _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
