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Flip-Flop Macros
Published in Murat Uzam, PIC16F1847 Microcontroller-Based Programmable Logic Controller, 2020
Example 4.7 explains the implementation of an asynchronous decade counter by using the PIC16F1847-Based PLC. The binary counters have 2n states, where n is the number of flip-flops. Counters with fewer than 2n states are designed with truncated sequences. These sequences are achieved by forcing the counter to recycle before going through all of its normal states. A common modulus for counters with truncated sequences is 10. A counter with 10 states in its sequence is called a decade counter. An asynchronous decade counter designed by using falling edge–triggered T flip-flops is shown in Figure 4.45. An asynchronous decade counter counts sequence from 0000 to 1001 (from 0 to 9 in decimal). Clock inputs of all flip-flops are cascaded and the T input of each flip-flop is connected to HIGH. This means that in the asynchronous decade counter, the flip-flops are connected in toggle mode and they will toggle at each negative-going edge (falling edge) of their respective clock signal. The clock input is connected to the first flip-flop. The other flip-flops receive the clock signal input from the Q output of the previous flip-flop. Once the counter counts to 10 (1010), all the flip-flops are cleared by means of the AND gate. Notice that only Q1 and Q3 are used to decode the count of 10. This is called partial decoding, as none of the other states (0 to 9) have both Q1 and Q3 HIGH at the same time.
Measurement Systems: Calibration and Response
Published in Patrick F. Dunn, Michael P. Davis, Measurement and Data Analysis for Engineering and Science, 2017
Patrick F. Dunn, Michael P. Davis
Typically, magnitude attenuation is given in units of dB/decade or dB/octave. A decade is defined as a 10-fold increase in frequency (any 10:1 frequency range). An octave is defined as a doubling in frequency (any 2:1 frequency range). For example, using the information in Figure 9.13, there would be an attenuation of approximately −8 dB/octave [= 20log(0.2) − 20log(0.5)] in the frequency range 1 ≤ ω/ωn ≤ 2 when ζ = 1.
Measurement Systems: Calibration and Response
Published in Patrick F. Dunn, Fundamentals of Sensors for Engineering and Science, 2019
Typically, magnitude attenuation is given in units of dB/decade or dB/octave. A decade is defined as a 10-fold increase in frequency (any 10:1 frequency range). An octave is defined as a doubling in frequency (any 2:1 frequency range). For example, using the information in Figure 6.13, there would be an attenuation of approximately –8 dB/octave [= 20log(0.2) – 20log(0.5)] in the frequency range 1 ≤ ω/ωn ≤ 2 when ζ = 1.
Ideas for Improving the Digital Design Lab
Published in IETE Journal of Education, 2023
Synchronous counters can be designed using JK, D, or T flip-flops. The minimum number of flip-flops required to build a synchronous counter is log2n, where n is the number of states. A counter can be a binary up/down counter [10,13], or a counter that generates a specific sequence. A binary up-counter of k bits will generate the sequence {0, 1, 2, … , 2k–1}. A modulo-m counter generates the sequence {0,1,2, … ,m−1}. A modulo-10 counter is also called a decade counter. An example of a 3-bit sequence generator is a circuit that generates the sequence {0, 1, 3, 2, 4, … }.