Gated precision offset circuit for a digital meter having a dual slope analog-to-digital converter
AssigneeSangamo Weston, Inc.
InventorsIrwin Munt, Philip Emile, Jr., John G. Walden
Life of this patent
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Abstract
An offset circuit for use in providing an offset signal to an analog-to-digital converter. The analog-to-digital converter has an integrator for performing signal integrate operations and is connected to a digital display. The offset circuit is gated to provide a variable offset current directly to the integrator of the analog-to-digital converter, thereby eliminating adverse loading effects on the high input impedance of the analog-to-digital converter.
Claims7
In a dual slope analog-to-digital converter, said converter having an integrator and including means for generating a control signal responsive to an integrate operation, the improvement comprising:
- means for generating a user selectable offset signal for application to said integrator including:
- an offset signal source, said offset signal having a magnitude which is continuously variable by a user;
- means, selectable by a user, for selecting or disabling said offset signal;
- logic means, responsive to said integrate control signal and to said offset selecting means for generating a gating signal;
- and
- switch means, responsive to said gating signal, for applying said offset signal to an input of said integrator only during said integrate operation.
Dependencies are inferred from the claim text.