An improved method of predistorting a transmit signal is disclosed whereby the
distortions occurring in all nonlinear subassemblies are compensated for using
a particularly suited feedback signal. Also disclosed are a transmitter, a transmitting
station, and a communications system using the method. The transmit signal, before
being converted to the desired radio frequency, is digitally predistorted at baseband
by digital signal processing means which are controlled by the feedback signal.
This signal is generated by a detector measuring the spectral power of the transmit
signal at the desired radio frequency both within a first frequency range, which
lies within the transmission spectrum, and within a second frequency range, which
lies outside the transmission spectrum. The digital predistortion disclosed is
flexibly parameterized and is adapted by the feedback control to the current behavior
of the transmitter subassemblies.