A novel RF to IF converter operates in two modes allowing both wide bandwidth
signals
and narrow bandwidth signals to be processed using the same wide bandwidth bandpass
filter as well as a dual-mode image-reject mixer. As a mobile receiver, both wide
bandwidth WCDMA or IMT-2000 signals and narrow bandwidth GSM signals pass through
the same wide bandwidth channel select filter. In the GSM mode, signals lying to
one side of the frequency range of the narrow GSM signal are attenuated by the
wide bandwidth channel select filter. Then signals lying to the other side of the
GSM signal are attenuated by an image-reject mixer. The image-reject mixer also
downconverts the GSM signal. In the WCDMA or IMT-2000 mode, the wide bandwidth
channel select filter attenuates signals outside of the WCDMA or IMT-2000 channel
bandwidth, and the image-reject mixer downconverts the wide bandwidth signal without
rejecting signals.