February 28, 1964 Electronics
[Table of Contents]
Wax nostalgic about and learn from the history of early electronics.
See articles from
published 1930 - 1988. All copyrights hereby acknowledged.
Admittedly, the only thing I
remember about Gray
Code (aka reflected binary) from college courses is that successive count values
change only one bit per increment, saving power in some digital circuits. The power
savings comes from the fact that, especially for CMOS circuits, current only flows
during the transition of a state change from "0" to "1" or from "1" to "0." Shaft
position encoders were and still are a primary application of Gray Code switching. If
the encoder output digital code is going to be used in a binary computation system,
then there is an advantage in generating a direct binary ("natural") count that does
not require a Gray-Code-to-Binary conversion circuit (or software routine). When the
Wayne-George Corporation introduced its paradigm-changing "Natural Code Non-Ambiguous Optical Encoder"
in 1964, those conversion circuits were probably not simple, compact, inexpensive
semiconductor IC's, but more likely vacuum tube behemoths. Even if IC's were used,
the conversion circuit would have been comprised of quad packs of AND's, OR's,
NAND's, and NOR's, not even a single application specific IC (ASIC). The difference
between the two types of encoders is very apparent in the advertisement. Close
inspection reveals that the Gray Code version produces only one bit change per step
whereas the binary version can result in every bit changing during a single step.
Natural Code Non-Ambiguous Optical Encoder
Why use a Cyclic-to-Natural Code Converter when
it is no longer necessary?
Now! Natural Code Non-Ambiguous Optical Encoders Exclusive from Wayne-George!
Typical Cyclic (Gray) Code Disk. Output is cyclic or inverted code and must be converted
to natural form for computation.
Wayne-George Natural Code (Binary) Disk. Output is non-ambiguous, natural code produced
directly without conversion from cyclic code.
Only Wayne-George offers a complete line of optical shaft-angle encoders providing
direct, non-ambiguous natural code outputs without code conversion. The new DIGISEC®
and "N" Series DIGISYN® encoders completely obsolete encoders using inverted or cyclic
(Gray) codes and their conversion equipment.
The DIGISEC and "N" Series DIGISYN encoders cover accuracies and resolutions (per
turn) ranging from several minutes of arc to one second of arc. Natural binary, binary
coded decimal or other natural codes are available. Outputs are DC levels in parallel
form and are continuously available. There is no limit to interrogation rate. Integral
code displays can be provided.
High reliability is attained through solid state circuits and long-life incandescent
lamps using low voltages and low power.
Shown is an NB-15 DIGISYN. The "N" Series cover the range from 5 to 17 Binary Digits.
Shown is 0-19 Digit DIGISEC.
The DIGISEC Series cover the range from 15 to 20 Binary Digits
322 Needham Street, Newton 64, Massachusetts (617) 969-7300
Posted August 23, 2018