Patent ID: 6954621

Claim:
A method of predistorting transmit signals in a transmitter comprising a power amplifier, said method comprising the steps of: predistorting the transmit signal, and amplifying the transmit signal at the desired radio frequency by means of the power amplifier and transmitting it, wherein the transmit signal is digitally predistorted at baseband and then up-converted to the desired radio frequency, the digital predistortion of the transmit signal being controlled by a feedback signal which 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 in the transmission spectrum, and within a second frequency range, which lies outside the transmission spectrum; and wherein the first and second frequency ranges are limited by means of respective bandpass filters, and that the spectral power is measured in these frequency ranges by down-converting the transmit signal from the desired radio frequency to an intermediate frequency, with the frequency of a local oscillator in a mixer being variable, so that it is possible to measure in the entire transmit-signal band.