a modification of a number system, esp a binary code, in which any adjacent pair of numbers, in counting order, differ in their digits at one position only, the absolute difference being the value 1
A binary sequence with the property that only one bit changes between any two consecutive elements (the two codes have a Hamming distance of one).
The Gray code originated when digital logic circuits were built from vacuum tubes and electromechanical relays. Counters generated tremendous power demands and noise spikes when many bits changed at once. E.g. when incrementing a register containing 11111111, the back-EMF from the relays’ collapsing magnetic fields required copious noise suppression. Using Gray code counters, any increment or decrement changed only one bit, regardless of the size of the number.
Gray code can also be used to convert the angular position of a disk to digital form. A radial line of sensors reads the code off the surface of the disk and if the disk is half-way between two positions each sensor might read its bit from both positions at once but since only one bit differs between the two, the value read is guaranteed to be one of the two valid values rather than some third (invalid) combination (a glitch).
One possible algorithm for generating a Gray code sequence is to toggle the lowest numbered bit that results in a new code each time. Here is a four bit Gray code sequence generated in this way:
0 0 0 0 0 0 0 1 0 0 1 1 0 0 1 0 0 1 1 0 0 1 1 1 0 1 0 1 0 1 0 0 1 1 0 0 1 1 0 1 1 1 1 1 1 1 1 0 1 0 1 0 1 0 1 1 1 0 0 1 1 0 0 0
The codes were patented in 1953 by Frank Gray, a Bell Labs researcher.
adjective pertaining to a working class with some manual labor, e.g. mechanics, maintenance, food preparation Examples Gray-collar refers to occupations that incorporate some of the elements of both blue and white collar. Word Origin 1963
- Gray column
gray column n. Any of the three masses of gray matter that extend longitudinally through the center of each lateral half of the spinal cord and appear as gray horns in transverse sections.
- Gray degeneration
gray degeneration n. The degeneration of the white substance of the spinal cord, the fibers of which lose their myelin sheaths and become darker in color.
noun 1. any of several ducks in which certain immature or female plumages are predominantly gray, as the gadwall and the pintail.