Self adjusting digital image rejection receiver for mobile communications

We present a receiver capable of capturing two RF channels at the same time with a single RF front end and single IF stage. The idea is to use the lowest possible IF plus a digital image rejection unit that can separate two adjacent RF channels with a negligible cochannel's image interference. We analyze two procedures of compensating, in the IF range, any gain and phase misadjustments generated in the I+Q mixing section that could produce image bands in any of the channels. The first one needs the help of an internal reference or pilot signal whereas the second one implements a blind procedure that only needs the current working signals.