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The data launched by the third flip-flop has to be captured by the first flip-flop in the next clock cycle for correct functionality. The path is Q out-> NOR -> AND -> J in . Also it is the critical p …

When clock = 0 NAND2 and NAND3 outputs are 1, simply because one of its inputs became 0 (clock). Hence S and R becomes 1 and remains at 1 as long as clock is 0. (R,S) = (1,1) => (Q,Q') holds presen …

What you have in the figure and waveforms is a positive D Latch (Master Latch) cascaded with a negative D Latch (Slave Latch). Together, this Master-Slave configuration act as a negative edge-triggere …

Possible setup violation because data may not be stable in the setup-hold window. And hence the output Q is unpredictable. If you add a buffer in the clock path of the flip-flop, such that it introduc …

The problem with simple JK latch is the race condition. Race condition is that as long as the clock is high, when the propagation delay is less than the pulse period, the output toggles between 0 and …

The first one is a negative-edge-triggered D flip-flop with clock enable. When EN is high, the input at D is latched on to the flip-flop at the falling edge of the clock. When EN is low, the previous …

I was going to feed Q back into D with an inverter such that it is toggled when clocked ( would this need a delay to not violate the hold time on D?) It's quite unlikely. There won't be any hold vio …

The problem with asynchronous counter is the "ripple". Say take an example of 4-bit asynchronous counter counting up. The transition from 0111 --> 1000 goes through or ripple through 3 intermediate s …

Preset and Clear are two asynchronous inputs in a Flip-Flop. "Preset" is used to set its output to '1' and "Clear" is used to reset its output to '0'. Active-low Preset means the Flip-Flop output …

\$t_{pcq}\$ is the clock to Q propagation delay of a flip-flop. That is the amount of time to propagate the value at D to its Q, after a rising edge clock edge has appeared. Known as simply propagatio …

While assertion of an Asynchronous Reset is not an issue, de-assertion can be an issue if it happens near clock edge. Asynchronous signals like Asynchronous Resets hence have to satisfy two timing ch …

D flip-flop provided by Logisim which you used for simulation was a positive edge-triggered D Flip-Flop. While what you have designed is a level-sensitive D latch. You have to cascade two of those D l …

\$ n \$ flip-flops can represent \$ 2^n \$ states. The number of bits needed to represent all the states will be the number of flip-flops needed to implement that state machine. So for this state diag …

Counters are made from flip-flops. This is also a counter which produces different counts on each clock cycle, based on the inputs X and Y. This is an asynchronous counter because the first flip-flop …

No problem with the circuit. The problem is the way you have simulated. When you toggle D at the exact moment of the rising edge of the clock, the HDL simulator will take only its past value. For eg., …