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Calibration of Analog Channels

IP.com Disclosure Number: IPCOM000080707D
Original Publication Date: 1974-Feb-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Kennedy, PJ: AUTHOR

Abstract

In the normal use of computers for processing systems, it is often necessary to convert from analog quantities to digital values or vice versa. Such conversion will be done by use of ladder-type resistance networks, voltage dividers, etc., and these, due to the requirements for accuracy are usually made of very high precision and stable components. The supply of these components is limited and they are quite expensive.

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Calibration of Analog Channels

In the normal use of computers for processing systems, it is often necessary to convert from analog quantities to digital values or vice versa. Such conversion will be done by use of ladder-type resistance networks, voltage dividers, etc., and these, due to the requirements for accuracy are usually made of very high precision and stable components. The supply of these components is limited and they are quite expensive.

By the use of the present procedures, less accurate components may be used with substantial hardware savings at a cost of a small increase in processing time. In the use of the procedure, after a system has been assembled with the lower cost components or at any later time during use, it is calibrated by using the system to measure precision standards of voltage, current or other quantities and the apparent measured values are stored in the processor. These values are used as data inputs in an algorithm which will determine the error factors such as zero offset, rate of change of error, etc., needed to correct the measured values to actual values.

These error factors are stored in a table in the processor's storage and whenever any unknown quantity is measured thereafter, the apparent value is modified by the use of the error factors from the stored table to generate an improved and more accurate indication of the value of the quantity. Since the laboratory standards can be more precise than the production hardware, e...