such as the mixer 20 see fig1 the im 2 current generated by the mixer 20 can be expressed in the form i im2mix t a 2mix u00b7 v rf t 2 1 expressing v rf in polar form and taking into account that it may be attenuated by some factor u03b1 mix and phase shifted by some phase u03c6 mix through the mixer circuitry we obtain i im2mix t a 2mix u00b7 u03b1 mix u00b7 a t cos u03c9 rf u00b7 t u03c6 t u03c6 mix 2 2 a portion of the signal represented by equation 3 is dependent on a value 2 u03c9 rf this portion of equation 3 is of little concern in this analysis since it is very high frequency and will be filtered away using conventional techniques however the low frequency part could land inside the desired baseband channel so the im 2 product of interest from equation 3 is i im2mixlf u2061 t 1 2 u00b7 a 2 u2062 mix u00b7 u03b1 mix 2 u00b7 a u2061 t 2 4 similarly the im 2 compensation current generated at the output of the vga 110 in fig2 is given by i im2cal u2061 t 1 2 u00b7 a cal u00b7 a u2061 t 2 5 where a cal is a programmable scaling factor cancellation of im 2 by the adder 114 is achieved when thus im 2 cancellation should be possible independently of the rf phase shift u03c6 mix through the mixer in a typical implementation of the rf block 102 the mixer cores are the main im 2 contributors therefore to improve tracking between the im 2 source i e the mixer core and the im 2 calibration signal it would.