What is a Johnson counter?
1 Answer
A Johnson counter, also known as a ring counter or a walking ring counter, is a type of digital sequential circuit used in digital electronics and digital signal processing. It is a specific implementation of a shift register that circulates a single high-bit ("1") through a series of flip-flops, creating a shifting pattern as the output.
The Johnson counter consists of a chain of flip-flops, where each flip-flop output is connected to the input of the next flip-flop in the sequence, forming a closed loop. The output of the last flip-flop is then fed back to the input of the first flip-flop, completing the loop.
The counter has two states, represented by the two possible patterns of bits it can generate. For an n-bit Johnson counter, there are 2^n possible states. It can circulate the "1" bit either in a right-shift (forward) or left-shift (reverse) direction, depending on the specific implementation.
Johnson counters are widely used in applications where a repeating pattern is required, such as in shift register sequences, frequency division, and control circuits. They are particularly useful when a simple, repeating sequence is needed with minimal external control.
It's worth noting that there are variations of Johnson counters, such as the twisted ring counter and the switch-tail ring counter, which add additional logic to alter the output sequence or optimize power consumption.
The Johnson counter consists of a chain of flip-flops, where each flip-flop output is connected to the input of the next flip-flop in the sequence, forming a closed loop. The output of the last flip-flop is then fed back to the input of the first flip-flop, completing the loop.
The counter has two states, represented by the two possible patterns of bits it can generate. For an n-bit Johnson counter, there are 2^n possible states. It can circulate the "1" bit either in a right-shift (forward) or left-shift (reverse) direction, depending on the specific implementation.
Johnson counters are widely used in applications where a repeating pattern is required, such as in shift register sequences, frequency division, and control circuits. They are particularly useful when a simple, repeating sequence is needed with minimal external control.
It's worth noting that there are variations of Johnson counters, such as the twisted ring counter and the switch-tail ring counter, which add additional logic to alter the output sequence or optimize power consumption.