Patent ID: 8238838

Claim:
A method of calibration of a transmit signal to be transmitted in a device simultaneously receiving and transmitting signals in a communication system, which device comprises a receiving path for a receive signal (RXS), a transmit path for the transmit signal (TXS), a calibration path for a correction signal (CS), the transmit signal being also received in the receiving path and the transmit signal and the receive signal being separated by a predetermined frequency band gap, wherein the transmit signal (TXS) is inserted or leaks into the receiving path as a received transmit signal, the method comprising: down-converting the received transmit signal to an intermediate frequency by mixing the received transmit signal with a first local oscillator frequency in the receiving path, wherein the intermediate frequency substantially corresponds to the frequency band gap reduced by the intermediate frequency of the receive signal; deriving an analog correction signal from the received transmit signal converted down in the down-converting step, wherein the deriving step is performed in the calibration path; and calibrating the transmit signal by a one of acting with the analog correction signal on the transmit path upon the transmit signal and converting the analog correction signal into a digital correction signal and calibrating the transmit signal by acting with the digital correction signal on the transmit path in the digital domain upon the digital transmit signal to be transmitted.