> >         I am now exploring linear encoding for a more digital solution.
> > I have come across a type of absolute position linear encoding called
> > binary chain code which is a _non-repeating_ pattern of ones and zeros of
> > length 2^N.  In an N-bit code _any_ N-bit sequence appears only once in
> > the entire 2^N pattern so you always know where your are.
>
> Is it better than standard way? I mean few parallel sensors and Gray coded
> strip.
Depends, the strip is only 1 bit wide and for a 16 bit resolution requires
a sense head 16 bits LONG not wide so may be possible to fit into smaller
spaces.

The problem that is solved with gray codes (only one bit changes at a time)
is not covered with the non repeating pattern code, you would need to either
have one more index track to indicate the read position or over sample the
code (16 x 4 = 64 ccd) and do edge detection and then read the center of the
bit position on all the code bits, remembering that you can have a sequence
of N (16) 1 bits which does make edge detection quite difficult.
--
Kalle Pihlajasaari     kalle@data.co.za
Interface Products     Box 15775, Doornfontein, 2028, South Africa
+27 (11) 402-7750      Fax: +27 (11) 402-7751