scope:

This handbook describes the operation of contact and non-contact (formerly brush and brushless) shaft-position, analog-to-digital encoders. It contains physical descriptions and illustrations of encoders, techniques used, theory of operation, background information on binary codes, coding principles and limitation, definitions of encoder terminology, and other criteria for selecting an encoder including identification and marking of encoders for military use.

In many situations, data to be measured can only, or most easily, be extracted in analog form. Since much of the available measurement readout equipment operates on the decimal system (decimal data inputs), the analog data to be measured must be changed to digital form. Encoders and associated equipment perform this function. This particular handbook is concerned primarily with encoders that receive the input in the form of a change in shaft position. However, many of the principles herein are applicable to all types of encoders.

It is the intent of this handbook to familiarize personnel with encoders and encoder operation so that intelligent choices can be made in system design. It is intended primarily for use by engineers, technically oriented personnel, or management personnel who wish to learn the general background of encoders. As such it is neither all inclusive nor fundamental oriented. Knowledge of the contents herein should provide the background for constructive conferences with encoder representatives in solving system design problems.