A wireless communications transceiver system and a variable gain mixer used in
the wireless communications transceiver system. The differential mixed output signal
of the variable gain mixer is a constant current signal. The gain of the mixer
is set by selectively connecting into the input section circuit of the mixer a
degeneration impedance. By maintaining the current of the mixed output signal constant,
the linearity of the variable gain mixer is maintained constant and there are no
changes in harmonic rejection.
