Frequency tuning of narrowband low noise amplifiers

摘要

A radio frequency (RF) receiver that includes a low noise amplifier (LNA), a tunable resonant circuit, and a processor for performing calibration of the RF receiver. The processor is configured to sweep the tunable resonant circuit through a dynamic range of resonant frequency settings while estimating noise signal output power at the LNA at each setting. The processor is also configured to set the tunable resonant circuit to the setting that produces the greatest noise signal power output at the LNA.

主权项

1. A radio frequency (RF) receiver, comprising:
a low noise amplifier (LNA) having an input terminal for receiving a noise signal and an output terminal for outputting an amplified noise signal; a tunable resonant circuit coupled to the output terminal of the LNA; a mixer coupled to the LNA and configured to mix the amplified noise signal with a signal from a local oscillator to produce a down-converted noise signal; and a processor coupled to the mixer and to a control terminal of the tunable resonant circuit, the processor configured to
set the tunable resonant circuit to a plurality of settings,measure a power of the down-converted noise signal at each setting,determine a setting corresponding to a greatest power of the down-converted noise signal, andset the tunable resonant circuit to the setting corresponding to the greatest power of the down-converted noise signal, wherein the processor is further configured to perform automatic gain control of the LNA, then stop the automatic gain control of the LNA prior to setting the tunable resonant circuit to the plurality of settings, measuring the power of the down-converted noise signal at each setting, and then start the automatic gain control of the LNA after setting the tunable resonant circuit to the setting corresponding to the greatest power of the down-converted noise signal.