A ring counter is a type of counter composed of a type circular shift register. The output of the last shift register is fed to the input of the first register. The hamming distance of a Johnson counter is 1, the hamming distance of an Overbeck counter is 2.
There are two types of ring counters:
- A straight ring counter or Overbeck counter connects the output of the last shift register to the first shift register input and circulates a single one (or zero) bit around the ring. For example, in a 4-register one-hot counter, with initial register values of 1000, the repeating pattern is: 1000, 0100, 0010, 0001, 1000... . Note that one of the registers must be pre-loaded with a 1 (or 0) in order to operate properly.
- A twisted ring counter, also called Johnson counter or Möbius counter (also Moebius), connects the complement of the output of the last shift register to the input of the first register and circulates a stream of ones followed by zeros around the ring. For example, in a 4-register counter, with initial register values of 0000, the repeating pattern is: 0000, 1000, 1100, 1110, 1111, 0111, 0011, 0001, 0000... .
Read more about Ring Counter: Four-bit Ring Counter Sequences, Johnson Counter(4-bits), Applications
Famous quotes containing the words ring and/or counter:
“Tell me where is fancy bred,
Or in the heart or in the head?
How begot, how nourished?
Reply, reply.
It is engendered in the eyes,
With gazing fed, and fancy dies
In the cradle where it lies.
Let us all ring fancy’s knell.
I’ll begin it. Ding, dong, bell.”
—William Shakespeare (1564–1616)
“As deaths have accumulated I have begun to think of life and death as a set of balance scales. When one is young, the scale is heavily tipped toward the living. With the first death, the first consciousness of death, the counter scale begins to fall. Death by death, the scales shift weight until what was unthinkable becomes merely a matter of gravity and the fall into death becomes an easy step.”
—Alison Hawthorne Deming (b. 1946)