Calibration apparatus for analog-to-digital converter
First Claim
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1. A calibration apparatus for an analog-to-digital converter, comprising:
- circuit means for controlling the DC level and the amplitude of an input signal applied thereto, the output signal from said circuit means being applied to said analog-to-digital converter;
reference signal generator means for generating first, second and third reference levels to be applied to said circuit means, said first reference level being intermediate said second and third reference levels; and
control means for controlling said circuit means in such a manner that the DC level of the output signal thereof is responsive to a digitized output from said analog-to-digital converter when the first reference level is applied to said circuit means, and that the amplitude of the output signal thereof is responsive to the difference between digitized outputs from said analog-to-digital converter when the second and third reference levels are applied to said circuit means.
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Abstract
A calibration apparatus for analog-to-digital converter or transient recorder including both analog and digital sections is disclosed. A built-in calibrator automatically calibrates the gain and DC level of the entire system to substantially the same accuracy as that of the digital section, thereby avoiding relatively large errors of the analog section. The amplitude or gain calibration is always performed over the full range of the digitizer used in the digital section.
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Citations
14 Claims
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1. A calibration apparatus for an analog-to-digital converter, comprising:
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circuit means for controlling the DC level and the amplitude of an input signal applied thereto, the output signal from said circuit means being applied to said analog-to-digital converter; reference signal generator means for generating first, second and third reference levels to be applied to said circuit means, said first reference level being intermediate said second and third reference levels; and control means for controlling said circuit means in such a manner that the DC level of the output signal thereof is responsive to a digitized output from said analog-to-digital converter when the first reference level is applied to said circuit means, and that the amplitude of the output signal thereof is responsive to the difference between digitized outputs from said analog-to-digital converter when the second and third reference levels are applied to said circuit means. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A transient recorder, comprising:
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an amplifier with controllable gain and DC level for amplifying an input analog signal; an analog-to-digital converter for digitizing the output signal from said amplifier; a memory for storing the digital output from said analog-to-digital converter; a calibrator for generating three different reference levels to be applied selectively to the input of said amplifier; and a control circuit responsive to the digital outputs from said analog-to-digital converter when the reference levels are applied to said amplifier for controlling the DC level of said amplifier in response to the intermediate value of the digital outputs and for controlling the gain thereof in response to the difference between the maximum and minimum values of the digital outputs. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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Specification