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Circuit Description

This circuit implements a 4-bit dual-code to Gray-code converter. Note that only one bit changes from one code word to the next in the Gray code.

One common use for the Gray-code is in position or angle-encoders, because the position (rotation) error due to misalignment is at most one bit. There is no such guarantee for a binary coded sensor, because the value at a position between the 00...0 and 11...1 states could be of any value.

The following image shows a 5-bit rotation encoder, using a Gray-code pattern in front of an optical sensor.

(The original page with more details and images about rotation angle sensors can be found here).