Systems and methods are disclosed for an electronically adjustable signal
filter system, which comprises, in some embodiments, a first filter
coupled to an antenna coupling network and a second filter, a power
amplifier coupled to the first filter, an antenna connected to an antenna
coupling network, a pilot tone generator coupled to the first filter, and
a first signal source connected to the power amplifier and first filter.
In some embodiments, the power amplifier amplifies the first signal, the
first filter places a notch into the first signal transmitted to the
antenna coupling network, the antenna coupling network combines the first
signal and a second signal received from the antenna and transmits a
third signal to the second filter.