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US 8,427,232 B2Granted
Self-calibrating gain control system
AssigneeMaxLinear, Inc.
InventorsJames Qiu, Sridhar Ramesh
Life of this patent
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Abstract
A circuit for self-calibrating a gain control system samples the output of a digital amplifier coupled in series with one or more analog amplifiers to correct errors in a discrete stepped gain control. A digital gain control circuit controls both the digital amplifier and at least one analog amplifier to produce a smooth linear and continuous gain, wherein perturbations in the digital control of gain are smoothed by a signal applied to gain control circuit by a gain step correction circuit.
Claims26
A step gain control system, comprising:
- an analog unit operable to change an amplification of an input signal according to a first gain step;
- and
- a digital unit operable to correct for the first gain step by an incremental adjustment of one or more second gain steps, the digital unit being in series with the analog unit and a magnitude of a second gain step being smaller than a magnitude of the first gain step, wherein the digital unit comprises a level detector operable to measure a digital signal level, wherein the digital unit comprises a filter for filtering the digital signal level over time, and wherein the change in amplification of the analog unit is associated with a slower response time and the incremental adjustment of the digital unit is associated with a faster response time.
A step gain control system, comprising:
- an analog unit operable to change an amplification of an input signal according to a first gain step;
- and
- a digital unit operable to correct for the first gain step by an incremental adjustment of one or more second gain steps, the digital unit being in series with the analog unit and a magnitude of a second gain step being smaller than a magnitude of the first gain step, wherein the digital unit comprises a level detector operable to measure a digital signal level, wherein the digital unit comprises a filter for filtering the digital signal level over time, and wherein the digital unit is operable to calibrate the incremental adjustment according a slow response time and a fast response time.
A step gain control system, comprising:
- an analog unit operable to change an amplification of an input signal according to a first gain step;
- and
- a digital unit operable to correct for the first gain step by an incremental adjustment of one or more second gain steps, the digital unit being in series with the analog unit and a magnitude of a second gain step being smaller than a magnitude of the first gain step, wherein the digital unit comprises a level detector operable to measure a digital signal level, wherein the digital unit comprises a filter for filtering the digital signal level over time, and wherein the level detector comprises a peak envelope power detector.
A method of gain control, comprising:
- changing an amplification of an input signal according to a first gain step in an analog unit;
- measuring a digital signal level;
- and
- correcting for the first gain step by applying an incremental adjustment of one or more second gain steps in a digital unit, the digital unit being in series with the analog unit and a magnitude of a second gain step being smaller than a magnitude of the first gain step, wherein correcting for the first gain step comprises filtering the digital signal level over time, and wherein the change in amplification of the analog unit is associated with a slower response time and the incremental adjustment of the digital unit is associated with a faster response time.
1 more element
A gain control system, comprising:
- an analog amplifier operable to amplify an analog signal, wherein a gain of the analog amplifier changes according to a first gain step;
- an analog to digital converter operable to convert the amplified analog signal to a digital signal;
- a level detector operable to measure a digital signal level, wherein the level detector comprises at least one of a root-mean-square (RMS) signal detector and a peak envelope power detector;
- and
- a digital amplifier operable to receive the digital signal and correct for the first gain step according to the level of the digital signal, a gain of the digital amplifier changing incrementally by one or more second gain steps, wherein each second gain step is smaller than the first gain step.
2 more elements
A step gain control system, comprising:
- an analog unit operable to change an amplification of an input signal according to a first gain step;
- and
- a digital unit operable to correct for the first gain step by an incremental adjustment of one or more second gain steps, the digital unit being in series with the analog unit and a magnitude of a second gain step being smaller than a magnitude of the first gain step, wherein the digital unit comprises a level detector operable to measure a digital signal level, wherein the digital unit comprises a filter for filtering the digital signal level over time, and wherein the digital unit comprises a gain step correction circuit operable to control the incremental adjustment of the one or more second gain steps based on the digital signal level and the first gain step.
A method of gain control, comprising:
- changing an amplification of an input signal according to a first gain step in an analog unit;
- measuring a digital signal level;
- and
- correcting for the first gain step by applying an incremental adjustment of one or more second gain steps in a digital unit, the digital unit being in series with the analog unit and a magnitude of a second gain step being smaller than a magnitude of the first gain step, wherein correcting for the first gain step comprises filtering the digital signal level over time, and wherein the digital unit comprises a gain step correction circuit operable to control the incremental adjustment of the one or more second gain steps based on the digital signal level and the first gain step.
1 more element
Dependencies are inferred from the claim text.