The Nyquist stability criterion and the Routh criterion both are powerful analysis tools for
determining the stability of feedback controllers. Identify which of the following statements
is FALSE.
A
The closed-loop frequency response for a unity feedback system cannot be obtained
from the Nyquist plot.
B
The Routh criterion is not applicable in the condition of transport lag, which can be
readily handled by the Nyquist criterion.
C
The general shape of the Nyquist plot is readily obtained from the Bode magnitude plot
for all minimum-phase systems.
D
Both the criteria provide information relative to the stable gain range of the system.
2
GATE ECE 2018
Numerical
+2
-0
The figure below shows the Bode magnitude and phase plots of a stable transfer function
Consider the negative unity feedback configuration with gain k in the feedforward path.
The closed loop is stable for k < k0. The maximum value of k0 is ______.
Your input ____
3
GATE ECE 2018
Numerical
+1
-0
A traffic signal cycles from GREEN to YELLOW, YELLOW to RED and RED to GREEN.
In each cycle, GREEN is turned on for 70 seconds, YELLOW is turned on for
5 seconds and the RED is turned on for 75 seconds. This traffic light has to be implemented
using a finite state machine (FSM). The only input to this FSM is a clock of 5 second period.
The minimum number of flip-flops required to implement this FSM is _______.
Your input ____
4
GATE ECE 2018
Numerical
+2
-0
In the circuit shown below, a positive edge-triggered D Flip-Flop is used for sampling input
data Din using clock CK. The XOR gate outputs 3.3 volts for logic HIGH and 0 volts for
logic LOW levels. The data bit and clock periods are equal and the value of $${{\Delta T} \over {{T_{CK}}}}$$ = 0.15,
where the parameters $$\Delta T$$ and TCK are shown in the figure. Assume that the Flip-Flop and the
XOR gate are ideal.
If the probability of input data bit (Din) transition in each clock period is 0.3, the average
value (in volts, accurate to two decimal places) of the voltage at node X, is _______.
