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US 9,319,027 B1Granted
Injecting a tone for image rejection calibration
AssigneeSilicon Laboratories Inc.
InventorAslamali A. Rafi
Life of this patent
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Abstract
In an example, apparatus comprises: a low noise amplifier (LNA) including a first transconductor having an input to receive a differential input radio frequency (RF) signal and an output to output a differential amplified RF signal to a RF signal path; and a second transconductor having an input coupled to a first common mode node and a second common mode node to receive a test tone signal and an output to output an amplified test tone signal to the RF signal path.
Claims20
An apparatus comprising:
- a low noise amplifier (LNA) comprising a first transconductor having an input to receive a differential input radio frequency (RF) signal via a first differential signal line and a second differential signal line and an output to output a differential amplified RF signal to a RF signal path;
- and
- a second transconductor having an input coupled to a first common mode node and a second common mode node coupled between the first differential signal line and the second differential signal line to receive a test tone signal and an output to output an amplified test tone signal to the RF signal path, wherein the first common mode node is coupled between first and second parallel capacitors and the second common mode node is coupled between third and fourth parallel capacitors.
A tuner comprising:
- a radio frequency (RF) signal path having a first signal path portion and a second signal path portion;
- a first differential transconductor coupled to receive a RF signal via the first signal path portion and the second signal path portion and to output an amplified RF signal to a mixer;
- a first pair of capacitors coupled between the first signal path portion and the second signal path portion and having a first common mode node adapted between the first pair of capacitors;
- a second pair of capacitors coupled between the first signal path portion and the second signal path portion and having a second common mode node adapted between the second pair of capacitors;
- and
- a second differential transconductor coupled to receive a test signal from the first common mode node and the second common mode node in a test mode and to output a test output to the mixer.
3 more elements
A method comprising:
- disabling a low noise amplifier (LNA) of a receiver during a test mode;
- enabling an injection source of the receiver during the test mode, the injection source coupled between common mode nodes at an input of the LNA and an input of a transconductor, wherein a first common mode node of the common mode nodes is coupled between first and second parallel capacitors and a second common mode node of the common mode nodes is coupled between third and fourth parallel capacitors, the transconductor having an output to couple to an output of the LNA during the test mode;
- injecting, via the injection source, a tone into the receiver at a frequency of an image band;
- measuring a signal power in a desired band responsive to processing the injected tone in the receiver;
- and
- calibrating an image rejection circuit of the receiver based at least in part on the signal power.
3 more elements
Dependencies are inferred from the claim text.