  We analyze the effect of bichromatic microwave irradiation on the
magnetoresistivity of a two dimensional electron system. We follow the model of
microwave driven Larmor orbits in a regime where two different microwave lights
with different frequencies are illuminating the sample ($w_{1}$ and $w_{2}$).
Our calculated results demonstrate that now the electronic orbit centers are
driven by the superposition of two harmonic oscillatory movements with the
frequencies of the microwave sources. As a result the magnetoresisitivity
response presents modulated pulses in the amplitude with a frequency of
$\frac{w_{1}-w_{2}}{2}$, whereas the main response oscillates with
$\frac{w_{1}+w_{2}}{2}$.
