Answer1

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WHAT'S YOUR ENGINEERING QUOTIENT?

Problem 5—What is the counting sequence of a three bit "twisted ring" counter?

Answer:

A 3-bit twisted ring counter has the following counting sequence:

000
100
110
111
011
001
:
:

or it can also be:

000
001
011
111
110
100
:
:

Observe that the twisted ring sequences are obtained by inverting one of the end bits (MSB or LSB) and shifting it into the other end bit.

From the above sequences, we can observe that there are 6 states. There are two illegal states (010 and 101), which if entered, will loop to each other in a 2-state sequence. Additional logic is required to move from these states to the correct sequence.

Twisted ring counters are used for symmetric code generation.

Contributor: Naveen P N

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