Patent ID: 7120414

Claim:
A frequency mixer comprising: a first differential amplifier for amplifying a first pair of input signals (RF 1 , RF 2 ) having a first frequency (f 1 ) to output a first differential output signal; a second differential amplifier for amplifying a second pair of input signals orthogonal to the first input signals to output a second differential output signal, the second pair of input signals having a substantially same frequency as the first frequency (f 1 ); a subtracter for subtracting the second differential output signal from the first differential output signal to output a subtracted output signal; and a mixer for mixing the subtracted output signal, and a first pair of drive signals having a second frequency (f 2 ) and a second pair of drive signals orthogonal to the first pair of drive signals and having the second frequency (f 2 ), wherein the mixer has a sub-harmonic double balanced mixing mode, and for outputting a pair of output signals orthogonal to each other, wherein at least one harmonic is cancelled from the output signals.