Method and apparatus for calibrating a gain control circuit
AssigneeAnalog Devices, Inc.
InventorsMichael Mueck, Paul F. Ferguson, Jr.
Life of this patent
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Abstract
A system includes a digital-to-analog converter circuit and a calibration circuit. The digital-to-analog converter circuit includes a gain control circuit providing volume adjustment. The system includes a calibration mode and a normal mode of operation. During calibration, a correction value associated with the gain control circuit is measured by the calibration circuit and stored. During normal operation, the stored correction value is combined with the input before provision of the same to the DAC circuit such that, for a predetermined input of midscale code, the desired system output remains constant despite any change in the volume setting of the gain control circuit.
Claims19
A system comprising:
- a gain control circuit having an input terminal and an output terminal, receiving an input signal on the input terminal and providing an output signal on the output terminal;
- a calibration circuit, coupled to the gain control circuit, receiving the output signal and producing and storing an correction value for the gain control circuit during a calibration cycle;
- and
- a summing block, coupled to the calibration circuit and the gain control circuit, combining the stored correction value with the input signal such that, for a predetermined input signal, the output signal remains substantially constant despite any changes in the amount of attenuation or gain provided by the gain control circuit.
A system comprising:
- a gain control means having an input terminal and an output terminal, for adjusting the gain or attenuation of an input signal received on the input terminal to produce an output signal on the output terminal;
- calibration means, coupled to the gain control means, for measuring and storing a correction value for the gain control means during a calibration cycle;
- and
- summing means, coupled to the calibration means and the gain control means, for combining the stored correction value with the input signal such that, for a predetermined input signal, the output signal remains substantially constant despite any changes in the amount of attenuation provided by the gain control means.
A method for calibrating a system comprising the steps of:
- receiving an input signal on an input terminal;
- controlling the gain or attenuation of the input signal with a gain control circuit to produce an output signal on an output terminal;
- determining a correction value during a calibration cycle;
- storing the correction value;
- and
- combining the correction value with the input signal such that, for a predetermined input signal, the output signal remains substantially constant despite any changes in the amount of attenuation provided by the gain control circuit.
Dependencies are inferred from the claim text.