Re: GrayCode to Binary conversion
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
|
Not Categorized, Please Help
|
|
