Granted Patent B2

US 8,150,350 · App. 13/246,538 · Granted Apr 3, 2012

Abstract

Claims (14)

1. A method of tuning a input-related, second-order intercept point (IIP2) of a mixer in a receiver of a transceiver including a transmitter, comprising the steps of:

determining whether power output of the transmitter is greater than a predetermined power output level;

determining whether a received signal strength indication of the receiver is less than a predetermined received signal strength indication level;

providing values for a gain of an IIP2 estimator and an update rate of a IIP2 controller;

using the gain of the IIP2 estimator, performing an optimization algorithm for estimating an estimated value of an IIP2 coefficient that is proportional to second-order intermodulation distortion occurring in the mixer;

using the update rate of the IIP2 controller and the estimated value of the IIP2 coefficient, performing an optimization algorithm for changing a tuning voltage of the mixer;

waiting a period for a change to occur in one or both of the power output level of the transmitter and a received signal strength indication of the receiver;

after waiting the period, determining whether a change in one or both of the gain of the IIP2 estimator and the update rate of the IIP2 controller has occurred;

based upon one of or both the change of the power output level and the received signal strength indication, determining whether a change in one or both of the gain of the IIP2 estimator and the update rate of the IIP2 controller are required; and

if any such change is required, making a change in one or both of the gain of the IIP2 estimator and the update rate of the IIP2 controller, based upon information stored in a look-up table.

2. The method of claim 1 , wherein the step of performing the optimization algorithm for estimating the estimated value of the IIP2 coefficient includes a step of compensating for DC offset in the receiver, thereby reducing any degradation of the estimate caused by the presence of the DC offset.

3. The method of claim 2 , wherein the values for the gain of the IIP2 estimator and the update rate of the IIP2 controller are obtained from respective look-up tables, based upon the power output of the transmitter and the receiver signal strength indication of the receiver.

4. The method of claim 1 , wherein the optimization algorithm is a sign-sign least means squared optimization algorithm.

5. The method of claim 4 , wherein the sign-sign least means squared optimization algorithm has a variable step size, the variable step size depending on a magnitude of the IIP2 coefficient estimation.

Assignments (28)