Method and system for calibrating quadrature modulators

Abstract

A calibration method and system for reducing modulation errors in a telecommunication transmitter apparatus includes providing a pair of test signals, which are substantially in quadrature to each other, and to repeat an estimation loop. The estimation loop starts with generating a modulated signal by modulating the test signals (the modulation introducing a modulation error) and continues by obtaining a squared signal corresponding to the square of the modulated signal. A transformed signal corresponding to the squared signal in the frequency domain is then calculated. The estimation loop further includes calculating an error indicator, indicative of the modulation error, according to the modulus of the transformed signal. A compensation, to be applied to the test signals for counterbalancing the modulation error, is calculated according to the error indicator and is then applied to the test signals. The estimation loop is repeated until the error indicator reaches a threshold and an indication of the compensation resulting from a last iteration of the estimation loop is stored (for the application of the compensation to each pair of operative signals managed by the telecommunication transmitter apparatus during operation thereof).