Method for calibrating distortion cancelation in duplex communication systems

Abstract

A radio with a system for cancelation of noise, distortion, and interference products is calibrated using a test signal. The test signal is inserted in a radio transmit path, amplified, and down-converted. The test signal may be converted from the digital domain prior to amplification, and up-converted prior to amplification. The down-converted amplified test signal is compared with a signal in the receive path, to measure test signal distortion in the receive path. A distortion model is calibrated based on the test signal, and parameters of the distortion model may be stored.

1 . A method for calibrating a distortion canceling system in a radio, comprising:
 inserting a test signal in a radio transmit path;   amplifying the test signal;   down-converting the amplified test signal;   comparing the down-converted amplified test signal with a receive path signal to measure test signal distortion in the receive path signal; and   calibrating a distortion model based on the test signal distortion.   
     
     
         2 . The method of  claim 1 , further comprising modulating the test signal prior to amplifying it. 
     
     
         3 . The method of  claim 1 , further comprising converting the test signal from a digital domain to an analog domain prior to amplifying it. 
     
     
         4 . The method of  claim 1 , further comprising up-converting the test signal prior to amplifying it. 
     
     
         5 . The method of  claim 1 , further comprising storing parameters of the distortion model.