Re: GrayCode to Binary conversion
- Posted by Kat <kat at kogeijin.com> Nov 15, 2002
- 368 views
On 15 Nov 2002, at 19:34, euman at bellsouth.net wrote: <snip> > For those who might not know why Gray Code are used, here is a brief > explanation: A Gray Code is a special type of binary code that doesnt use > position weighting, in other words, each position does not have a specific > weight. Gray Code are setup so that as we progress from one number to the > next, > only one bit changes. Because only one bit changes at a time, the speed of > transition for Gray Code is considerably faster than BCD. Mechanically, for position encoders, it's faster, because you don't need to care about bit-change alignment, or when to clock the input into the digital equipment. That's why the gray code was invented. Bit phase jitter is a major pain to interfacing to the real world on mechanical systems, what with oscillation in shafts and vibration in supporting frames, and just general physical slop in the switches and encoders. It was a problem in tape drives, paper tape, and card readers. It is in AD and DA convertors too, actually, but that's solved with throwing more electronics at the problem. Or in one case i had to solve, by making all the lines to the 200Mhz ecl d/a chip the same length, pcb layout people are not engineers. Kat