Method and apparatus for DC offset calibration
AssigneeWionics Technologies, Inc.
InventorTurgut Aytur
Life of this patent
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Abstract
A variable amplifier with adjustable current to correct for DC offset. The variable amplifier includes a zero function, allowing for zeroing of some amplifiers in an amplifier chain during correction for DC offset of another amplifier in an amplifier chain. In some embodiments selectable current injection is provided to an amplifier chain in conjunction with signals from selectable mixers.
Claims23
A differential amplifier with DC offset reduction circuitry, comprising:
- a differential amplifier comprising a pair of transistors having their sources coupled to a current source and their drains each coupled to a resistance, differential amplifier adapted to receive a differential input at gates of the pair of transistors;
- and
- an adjustable current generator coupled to a drain of one of the transistors of the pair of transistors.
An amplifier chain including DC offset reduction capability, comprising:
- a plurality of differential amplifiers coupled in series,
- each of the differential amplifiers having an adjustable current generator coupled to a drain of at least one transistor of a differential transistor pair, and
- at least some of the differential amplifiers having a circuit path for selectively shunting current away from the differential transistor pair in response to a selection signal.
A radio frequency (RF) receiver, comprising:
- at least one mixer configured to downconvert an RF signal to a baseband signal;
- an amplifier chain coupled to the at least one mixer, the amplifier chain comprising a plurality of differential amplifiers coupled in series, each of the differential amplifiers having an adjustable current generator coupled to a drain of at least one transistor of a differential transistor pair, and at least some of the differential amplifiers having a circuit path for selectively shunting current away from the differential transistor pair in response to a selection signal;
- and
- processing circuitry configured to command adjustment of the adjustable current generators and to command selectively shunting of current away from the differential transistor pairs.
A method for reducing DC offset in a radio frequency (RF) receiver, comprising:
- evaluating a signal indicative of an output of a circuit element;
- and
- commanding a change in current generation by a current generator associated with the circuit element based on the evaluation of the signal indicative of the circuit element.
A method of reducing DC offset in a radio frequency (RF) receiver, comprising:
- effectively zeroing inputs to an amplifier in a chain of amplifiers;
- and
- commanding a change in current generation by a current generator associated with the amplifier based on a signal indicative of an output of the amplifier.
Dependencies are inferred from the claim text.