Gray Code

Archiver

Stampers,

Anyone have a listing or details on GRAY CODE?

I know it is a "sort of" binary code where only one bit changes at a
time, but as for the sequence I have no idea!

Tim Stockman

Archiver

At 08:23 AM 9/19/2000 +0930, you wrote:
>Stampers,
>
>Anyone have a listing or details on GRAY CODE?
>
>I know it is a "sort of" binary code where only one bit changes at a
>time, but as for the sequence I have no idea!


Here ya go:

http://www.opticalencoder.com/copi_abs_enc.html

Gray code is an expanding binary sequence, where only a one-bit, bit change
is permitted during the expansion (iterative count). It's cumbersome on one
hand, but great for absolute encoders on the other. As the text will show,
a series of OR statements can be used for decoding.

I believe Tracy may have a "state machine" (which see) on his website for
decoding Grey code. It pretty much follows the cite above. Check on his
website at :

[noparse][[/noparse] http://ourworld.compuserve.com/homepages/emesys/BS2misc.htm ]


for the Gray code to binary routine.

Regards,

Bruce



>Tim Stockman

Archiver

The rule for generating Gray code: Start with all zeros. Then, to progress
to the next higher value, change only the least significant bit which
brings you to the new state. Horowitz and Hill cover this on page 477 (2nd
ed.)
4-bit Gray code is:


Value Gray code
MSb LSb

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0 0000
1 0001
2 0011
3 0010
4 0110
5 0111
6 0101
7 0100
8 1100
9 1101
A 1111
B 1110
C 1010
D 1011
E 1001
F 1000

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Steve Roberts: sroberts@s...

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