Residual carrier and side band processing system and method

Abstract

In a communication device, the LO leakage and opposite side band signals are measured at an output signal. Input processing signals to a modulator are adjusted in response to the measured values to minimize the LO leakage and maximize side band suppression.

1 - 18 . (canceled) 
   
   
       19 . A communication device-implemented method of processing communication signals, comprising:
 providing an in-phase baseband signal at a test frequency;   providing a quadrature baseband signal at the test frequency;   modulating a carrier signal by the in-phase and quadrature baseband signals to generate a modulated carrier signal;   measuring a LO leakage signal in the modulated carrier signal, the measuring step comprising:
 generating a calibration baseband signal having a frequency component, wherein the frequency component has an amplitude corresponding to the magnitude of the LO leakage signal in the modulated carrier signal; and 
 utilizing the calibration baseband signal to generate a digital value proportional to the magnitude of the frequency component, the first digital value comprising a LO leakage signal value; 
   adaptively adjusting at least one of an in-phase DC offset or a quadrature DC offset in response to an LO leakage signal measurement, the adjusting step comprising:
 adjusting at least one of the in-phase DC offset or the quadrature DC offset in response to the LO leakage signal measurement; 
 measuring an LO leakage signal after the adjustment to generate an updated LO leakage signal value; and 
 determining if the updated LO leakage signal value is below an LO leakage threshold value; and 
   repeating the adaptive adjustment step until the updated LO leakage signal value is below the LO leakage threshold value.   
   
   
       20 . The method of  claim 19 , wherein the frequency component comprises a sine wave at the test frequency having an amplitude corresponding to the magnitude of the LO leakage signal at a LO frequency in the modulated carrier signal. 
   
   
       21 . The method of  claim 19 , wherein the LO leakage signal measurement comprises at least one of the LO leakage signal value or the updated LO leakage signal value. 
   
   
       22 . The method of  claim 19 , wherein the generation of the calibration baseband signal comprises passing the modulated carrier signal through a non-linear operational circuit. 
   
   
       23 . The method of  claim 22 , wherein the non-linear operational circuit comprises a RF diode. 
   
   
       24 . The method of  claim 19 , wherein the generation of the calibration baseband signal is performed without utilizing a signal corresponding to the frequency of the carrier signal. 
   
   
       25 . The method of  claim 19 , wherein the LO leakage threshold value is a non-zero value. 
   
   
       26 . The method of  claim 19 , wherein:
 the in-phase baseband signal is substantially single tonal; and   the quadrature baseband signal is substantially single tonal.   
   
   
       27 . The method of  claim 19 , further comprising:
 precluding transmission of the modulated carrier signal.   
   
   
       28 . The method of  claim 19 , wherein the utilization of the calibration baseband signal to generate the digital value comprising the LO leakage value comprises:
 low pass filtering the calibration baseband signal;   digitizing the filtered calibration baseband signal to generate a digital calibration baseband signal; and   measuring the amplitude of the frequency component in the digital calibration baseband signal.   
   
   
       29 . The method of  claim 28 , wherein the low pass filtering of the calibration baseband signal comprises utilizing a cutoff frequency of three times the test frequency. 
   
   
       30 . The method of  claim 28 , wherein the digitizing of the filtered calibration baseband signal comprises utilizing a sampling frequency greater than four times the test frequency. 
   
   
       31 . A communication device-implemented method of processing communication signals, comprising:
 providing an in-phase baseband signal at a test frequency;   providing a quadrature baseband signal at the test frequency;   modulating a carrier signal by the in-phase and quadrature baseband signals to generate a modulated carrier signal;   measuring a side band signal in the modulated carrier signal, the measuring step comprising:
 generating a calibration baseband signal having a frequency component, wherein the frequency component has an amplitude corresponding to the magnitude of the side band signal in the modulated carrier signal; and 
 utilizing the calibration baseband signal to generate a digital value proportional to the magnitude of the frequency component, the first digital value comprising a side band signal value; and 
   adaptively adjusting at least one of an in-phase gain, a quadrature gain, or a channel correlation in response to a side band signal measurement, the adjusting step comprising:
 adjusting at least one of the in-phase gain, the quadrature gain, or the channel correlation in response to the side band signal measurement; 
 measuring a side band signal after the adjustment to generate an updated side band signal value; and 
 determining if the updated side band signal value is below the side band threshold value; and 
   repeating the adaptive adjustment step until the updated side band signal value is below the side band threshold value.   
   
   
       32 . The method of  claim 31 , wherein the frequency component comprises a sine wave at double the test frequency having an amplitude corresponding to the magnitude of the side band signal at a LO frequency minus the test frequency in the modulated carrier signal. 
   
   
       33 . The method of  claim 31 , wherein the side band signal measurement comprises at least one of the side band signal value or the updated side band signal value. 
   
   
       34 . The method of  claim 31 , wherein the side band threshold value is a non-zero value. 
   
   
       35 . The method of  claim 31 , wherein the adjusting of the channel correlation comprises an addition of a scale multiple of the in-phase baseband signal to the quadrature baseband signal. 
   
   
       36 . The method of  claim 31 , wherein the adjusting of the channel correlation comprises an addition of a scale multiple of the quadrature baseband signal to the in-phase baseband signal. 
   
   
       37 . The method of  claim 31 , wherein the adjusting of the channel correlation comprises adjusting a phase shift between the in-phase baseband signal and the quadrature baseband signal. 
   
   
       38 . A communication device-implemented method of processing communication signals, comprising:
 providing an in-phase baseband signal at a test frequency;   providing a quadrature baseband signal at the test frequency;   modulating a carrier signal by the in-phase and quadrature baseband signals to generate a modulated carrier signal;   measuring a LO leakage signal in the modulated carrier signal, the measuring step comprising:
 generating a calibration baseband signal having a frequency component, wherein the frequency component has an amplitude corresponding to the magnitude of the LO leakage signal in the modulated carrier signal; and 
 utilizing the calibration baseband signal to generate a digital value proportional to the magnitude of the frequency component, the first digital value comprising a LO leakage signal value; and 
   adaptively adjusting at least one of an in-phase DC offset or a quadrature DC offset in response to a LO leakage signal measurement, the adjusting step comprising:
 adjusting at least one of the in-phase DC offset or the quadrature DC offset in response to the LO leakage signal measurement; 
 measuring the LO leakage signal after the adjustment to generate an updated LO leakage signal value; and 
 determining whether the adaptive adjustment step is to be repeated based at least in part on the updated LO leakage signal value. 
   
   
   
       39 . The method of  claim 38 , wherein the LO leakage signal measurement comprises at least one of the LO leakage signal value or the updated LO leakage signal value. 
   
   
       40 . A communication device-implemented method of processing communication signals, comprising:
 providing an in-phase baseband signal at a test frequency;   providing a quadrature baseband signal at the test frequency;   modulating a carrier signal by the in-phase and quadrature baseband signals to generate a modulated carrier signal;   measuring a side band signal in the modulated carrier signal, the measuring step comprising:
 generating a calibration baseband signal having a frequency component, wherein the frequency component has an amplitude corresponding to the magnitude of the side band signal in the modulated carrier signal; and 
 utilizing the calibration baseband signal to generate a digital value proportional to the magnitude of the frequency component, the first digital value comprising a side band signal value; and 
   adaptively adjusting at least one of an in-phase gain, a quadrature gain, or a channel correlation in response to side band signal measurement, the adjusting step comprising:
 adjusting at least one of the in-phase gain, the quadrature gain, or the channel correlation in response to the sideband signal measurement; 
 measuring the side band signal after the adjustment to generate an updated side band signal value; and 
 determining whether the adaptive adjustment step is to be repeated based at least in part on the updated side band signal value. 
   
   
   
       41 . The method of  claim 40 , wherein the side band signal measurement comprises at least one of the side band signal value or the updated side band signal value.