A zero intermediate frequency (ZIF) radio frequency (RF) digital mixer
(200) includes a low noise amplifier (LNA) (203), a first RF mixer stage
(205) for mixing an RF signal from the at least one LNA with a first
local oscillator signal operating a first predetermined frequency. A
second RF mixer stage (207) is then utilized for mixing in-phase (I) and
quadrature (Q) digital signals from the first RF mixer stage (205) with a
plurality of second local oscillator signals (LO) operating at a second
predetermined frequency. The invention significantly improves current
drain by eliminating the need for a linear transconductance stage while
still maintaining high degrees of isolation and linearity.