Digital Logic
Q171.
Consider the circuit in the diagram. The \oplus operator represents Ex-OR. The D flip-flops are initialized to zeroes (cleared). The following data : 100110000 is supplied to the "data" terminal in nine clock cycles. After that the values of q_{2}q_{1}q_{0} areQ172.
Which of the following input sequences will always generate a 1 at the output z at the end of the third cycle?Q173.
You are given a free running clock with a duty cycle of 50% and a digital waveform f which changes only at the negative edge of the clock. Which one of the following circuits (using clocked D flip flops) will delay the phase of f by 180^{\circ} ?Q174.
In an SR latch made by cross-coupling two NAND gates, if both S and R inputs are set to 0, then it will result inQ176.
Choose the correct alternatives (more than one may be correct) and write the corresponding letters only: Advantage of synchronous sequential circuits over asynchronous ones is:Q177.
A 1-input, 2-output synchronous sequential circuit behaves as follows. Let z_{k},n_{k} denote the number of 0's and 1's respectively in initial k bits of the input ( z_{k}+n_{k}=k ). The circuit outputs 00 until one of the following conditions holds. 1. z_{k}-n_{k}=2. In this case, the output at the k -th and all subsequency clock ticks is 10. 2. n_{k}-z_{k}=2. In this case, the output at the k -th and all subsequent clock ticks is 01. What in the minimum number of states required in the state transition graph of the above circuit?Q178.
What is the final value stored in the linear feedback shift register if the input is 101101?Q179.
Consider the circuit given below the initial state Q_{0}=1, Q_{1}=Q_{2}=0. The state of the circuit is given by the value 4Q_{2}+2Q_{1}+Q_{0} Which one of the following is the correct state sequence of the circuit ?Q180.
The below figure shows four D-type flip-flops connected as a shift register using a XOR gate. The initial state and three subsequent states for three clock pulses are also given.\begin{array}{|c|c|c|c|c|} \hline \text{State} & Q_{A} & Q_{B} & Q_{C} & Q_{D} \\\hline \text{Initial} & 1 & 1 & 1 & 1 \\\hline \text{After the first clock} & 0 & 1 & 1 & 1 \\\hline \text{After the second clock} & 0 & 0 & 1 & 1 \\\hline \text{After the third clock} & 0 & 0 & 0 & 1 \\\hline \end{array}The state Q_{A} Q_{B} Q_{C} Q_{D} after the fourth clock pulse is