Patent ID: 6917815

Claim:
A concurrent, dual-band, image-rejection downconverter for a concurrent dual-band RF receiver having a front-end subsystem that supplies a front-end signal having two discrete desired frequency bands and a transfer function with attentuation regions at frequency bands outside the two discrete desired frequency bands, comprising: (a) a first image-rejection downconversion stage that receives and that is adapted to simultaneously downconvert the front-end signal to two intermediate frequency (IF) bands such that the image frequency bands of the two desired frequency bands fall at the attenuation regions of the front-end transfer function, and further comprising: (i) a first quadrature local oscillator (LO 1 ) block adapted to supply an in-phase (I) signal and a quadrature (Q signal of a first predetermined frequency; (ii) a first mixer connected to the LO 1 block and the front-end subsystem that is adapted to mix the in-phase LO 1 signal with the front-end signal and to supply a resultant in-phase intermediate frequency (IF) signal; and (iii) a second mixer connected to the LO 1 block and the front-end subsystem and adapted to mix the quadrature LO 1 signal with the front-end signal and to supply a resultant quadrature IF signal, wherein the first predetermined frequency of the LO 1 block is offset from the midpoint of the two desired bands such that the image frequency bands of the two desired bands fail at attenuation regions of the front-end transfer function; and (b) a subsequent image-rejection downconversion stage that downconverts the two IF bands.