29.12.2014 Views

A Symbolic Analysis of Relay and Switching Circuits

A Symbolic Analysis of Relay and Switching Circuits

A Symbolic Analysis of Relay and Switching Circuits

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

33<br />

It is easy to sP£w that the sum modulo two obeys the<br />

commutative, asso(}iative, <strong>and</strong> the distrihltive law<br />

with resoect to multiplication, i.e.<br />

x 1<br />

ex 2<br />

: ~exl<br />

(X 1 eX 2 )eX 3<br />

=X 1<br />

8(X 2<br />

eX 3<br />

)<br />

Also:<br />

x el : X'<br />

1 1<br />

Since the sum modulo two obeys the associative law,<br />

we may omit parentheses in a<br />

sum <strong>of</strong> several terms<br />

Without ambiguity_ The sum modulo two <strong>of</strong> the n var1-<br />

ables X 'A ••••X will for convenience be written:<br />

1 2 n<br />

Xlex2ex3···e~<br />

n<br />

=~Xk<br />

Theorem: The two functions <strong>of</strong> n variables which require<br />

the most elements (relay contacts) in a seriesn<br />

n<br />

parallel realization Bre ~X"<strong>and</strong> (~X~)I, each <strong>of</strong> wlUch<br />

requires (3·2 n - 1 _2) elements.<br />

12 1

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!