A transmitter circuit 10 with a first characteristic controllable by a first control signal and a second characteristic controllable by a second control signal is calibrated using a calibration method to enable accurate power control. The transmitter circuit 10 will typically comprise a VGA amplifier...http://www.google.de/patents/US7792493?utm_source=gb-gplus-sharePatent US7792493 - Transmitter and a method of calibrating power in signals output from a transmitter
