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US 8,265,584 B2Granted
Providing image rejection calibration for a receiver
AssigneeSilicon Laboratories Inc.
InventorsJohn Khoury, Mitch Reid, Majid Barazande-Pour
Life of this patent
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Abstract
According to one embodiment, a method for updating filter values of an image canceller is provided. The method may include determining a channel-to-image (C/I) ratio between a channel signal and an image signal at the canceller input and generating a gain control value based at least in part on the C/I ratio. Then correlations between the channel signal and the image signal at the canceller's input and output can be generated, along with a gear control value based at least in part on a ratio between the correlations. In turn, one or more filters of the canceller can be updated using the control values.
Claims27
An apparatus comprising:
- a signal channel path including a first mixer to receive an intermediate frequency (IF) signal and to downconvert the IF signal to a signal channel baseband signal;
- an image channel path including a second mixer to receive the IF signal and to downconvert the IF signal to an image channel baseband signal;
- an image rejection calibration unit to receive the signal channel baseband signal and the image channel baseband signal and including:
- a signal filter to receive a value of the signal channel baseband signal and to generate a filtered signal channel value;
- a first combiner to combine the signal channel baseband signal with a filtered image channel value to obtain a signal channel path output;
- an image filter to receive a value of the image channel baseband signal and to generate the filtered image channel value;
- a second combiner to combine the image channel baseband signal with the filtered signal channel value to obtain an image channel path output;
- and
- a signal correlator to correlate a current sample of the image channel path output with a current sample and at least one previous sample of the signal channel path output.
6 more elements
A system comprising:
- an antenna to receive a radio frequency (RF) signal;
- an analog front end to receive the RF signal from the antenna and to downconvert the RF signal to an intermediate frequency (IF) signal and to convert the IF signal to a digital complex signal;
- a digital signal processor (DSP) coupled to the analog front end, the DSP including an image canceller to perform image rejection, the image canceller including:
- a signal filter to receive a signal channel value and to generate a filtered signal channel value;
- an image filter to receive an image channel value and to generate a filtered image channel value;
- a first combiner to combine the signal channel value and the filtered image channel value to obtain a signal channel output;
- a second combiner to combine the image channel value and the filtered signal channel value to obtain an image channel output;
- a signal correlator to correlate a current sample of the image channel output with a current sample and at least one previous sample of the signal channel output, wherein the signal filter is to be updated based at least in part on an output of the signal correlator;
- and
- an image correlator to correlate a current sample of the signal channel output with a current sample and at least one previous sample of the image channel output, wherein the image filter is to be updated based at least in part on an output of the image correlator.
7 more elements
A method comprising:
- determining a channel-to-image (C/I) ratio between a channel signal and an image signal at an input to an image rejection unit, and generating a gain control value based at least in part on the C/I ratio;
- determining a first correlation between the channel signal and the image signal at the image rejection unit input and a second correlation between the channel signal and the image signal at an output of the image rejection unit, and generating a gear control value based at least in part on a ratio between the first and second correlations;
- and
- updating a first filter of the image rejection unit using the gain control value and the gear control value.
1 more element
Dependencies are inferred from the claim text.