China
Africa
Explore chapters and articles related to this topic
Force-System Resultants and Equilibrium
Published in Richard C. Dorf, The Engineering Handbook, 2018
generates a sequence in which a 1 moves from one position to the next position in the output pattern. For example, the outputs of a 5-bit ring counter follow the sequence: 10000,01000,00100,00010,00001, 10000,…. A Johnson counter or twisted ring counter is a ring counter whose final output is “twisted” before being fed back to the first stage, so that when the final output is a 1 the next value of the first output is a 0, and when the final output is a 0 the next value of the first output is a 1. The sequence for a 5 -bit Johnson counter is 10000,11000,11100,11110,11111,01111,00111,00011,00001,10000,…. Johnson counters have the characteristic that only one digit changes from one number in the sequence to the next number. This characteristic is particularly convenient in eliminating logic glitches that can occur in logic circuits using counter outputs. Logic glitches are unwanted logic pulses of very short duration.
Sequential Circuits
Published in Ronald C. Emery, Digital Circuits, 2020
The Johnson counter, sometimes called a "twisted ring," a "switch-tail ring" or a Moebius counter, is one of the most useful of the counter configurations. The Johnson counter strikes a pleasant middle course between the efficient binary counter, which requires maximum decoding circuitry but a minimum number of FFs, and the inefficient ring counter, which requires minimum decoding circuitry but a maximum number of FFs.
Additional Topics in Computer Arithmetic
Published in Joseph Cavanagh, Computer Arithmetic and Verilog HDL Fundamentals, 2017
A count-down counter was presented in Section 17.7. Another type of counter that is used for specific applications is a Johnson counter. This is a counter in which any two contiguous state codes (or code words) differ by only one variable. It is similar, in this respect, to a Gray code counter. A 4-bit Johnson counter counts in the sequence shown below, where y4 is the low-order bit.
Design of low power 16-bit counter with Programmable Combinational Logic and Integrated Clock Gating using 16-nm technology
Published in International Journal of Electronics, 2021
S Mohamed Sulaiman, B Jaison, M Anto Bennet
N-bit counter having 2 N states, the most significant bit (MSB) states remain longer than least significant bit (LSB) states. The traditional synchronous counters use Manchester carry chain (Kim et al., 2009) for accelerating the counting operation and fast carry propagation. In the meanwhile, length of convey chain, resistance, and capacitance additionally increase. So delay gets greater with the square of the length (Neil, 2006). Progressively over it has voltage wing. This technique is appropriate for a low arranged stage counter. For the multi-stage counter, it creates more opposition, capacitance and voltage swing. This likewise makes more delay. There is an aggregate of 8 clock pulses to each flip flop required to work a 4 bit Johnson counter. Thus, a sum of 32 pulses is required for a 4 bit counter. Yet, ordinary Johnson counter (Sharma & Singh, 2015) with clock gating framework has been utilised just to check clock pulses required in one cycle to each flip flop, which implies aggregate of 8 pulses are expected to work the 4 bit Johnson counter. In any case, in this strategy, a low-weighted piece of present state will be chosen, regardless of whether pass the clock or not.