A digital receiver for receiving an analog host signal with one or more
digital sidebands includes a bandreject filter arranged at least in part
in an intermediate frequency (IF) processing stage of the receiver. In an
illustrative embodiment, first and second digital sidebands are
transmitted on either side of a frequency modulated (FM) analog host
signal in a hybrid in-band on-channel (HIBOC) digital audio broadcasting
(DAB) system. The received composite signal is filtered in the IF
processing stage of the receiver by the bandreject filter in order to
substantially attenuate the analog host signal while passing the digital
sidebands. The bandreject filter may be arranged in the IF processing
stage so as to filter the analog host signal from the composite signal at
a point prior to an input of an automatic gain control (AGC) circuit, such
that the AGC operating point is determined primarily by the digital
sidebands. The bandreject filter may have a group delay characteristic for
a portion of a frequency spectrum associated with the digital sidebands
that is selected to equalize a corresponding group delay characteristic
for a signal path of the receiver.