Patent ID: 6952594
Filing Date: 2005-10-04
Classification: H04B

Abstract:
1. A communication apparatus including a dual mode receiver, the receiver comprising: a narrowband signal mixer adapted to downconvert a narrowband radio frequency (RF) signal to a narrowband intermediate frequency (IF) signal, wherein the narrowband IF signal having a narrowband IF signal carrier component, a first IF noise component having frequencies outside the narrowband IF carrier component, and a second IF noise component also having frequencies outside the narrowband IF carrier component, such that the narrowband IF carrier component lies within but near a limit of a predetermined range of signal frequencies; a bandpass filter connected to said narrowband signal mixer, said bandpass filter adapted to allow signals within the predetermined range to pass through such that, when the narrowband IF signal is introduced, the first IF noise component is filtered out while the narrowband IF carrier component and the second IF noise component passes through; and a dual-mode image-reject mixer (DMIRM) connected to said bandpass filter, said DMIRM adapted to attenuate the second IF noise component.