Why is the outermost ring of an optical encoder the least significant bit?

[engineer23]

Why is the outermost ring of an optical encoder the least significant bit? Is this somehow related to frequency?

 

[NoTime]

There is more length in the outside ring.
For a sensor of any given resolution the wider the disk the more lines that can be scribed on it.
While in a way this relates to frequency, it is more about sensor resolution.

 

[rbj]

just curious, does your optical encoder use Gray code? it should. if it does, the two LSBs (of Gray code) will have the same "frequency" but will be 90^o outa phase. just like the encoders of the earlier mice.