List of top Electronics and Communication Engineering Questions asked in GATE Electronics and Communication Engineering

An asymmetrical periodic pulse train \( v_{\text{in}} \) of 10 V amplitude with on-time \( T_{\text{on}} = 1 \, \text{ms} \) and off-time \( T_{\text{off}} = 1 \, \mu \text{s} \) is applied to the circuit shown in the figure. The diode \( D_1 \) is ideal. \[ \text{The difference between the maximum voltage and minimum voltage of the output waveform \( v_o \) (in integer) is V.} \] 

In the circuit shown in the figure, the switch is closed at time \( t = 0 \), while the capacitor is initially charged to \( -5 \, \text{V} \) (i.e., \( v_C(0) = -5 \, \text{V} \)). The time after which the voltage across the capacitor becomes zero (rounded off to three decimal places) is ms.

The impedance matching network shown in the figure is to match a lossless line having characteristic impedance \( Z_0 = 50 \, \Omega \) with a load impedance \( Z_L \). A quarter-wave line having a characteristic impedance \( Z_1 = 75 \, \Omega \) is connected to \( Z_L \). Two stubs having characteristic impedance of \( 75 \, \Omega \) each are connected to this quarter-wave line. One is a short-circuited (S.C.) stub of length \( 0.25 \lambda \) connected across PQ and the other one is an open-circuited (O.C.) stub of length \( 0.5 \lambda \) connected across RS. The impedance matching is achieved when the real part of \( Z_L \) is: 

The electrical system shown in the figure converts input source current \( i_s(t) \) to output voltage \( v_o(t) \). \[ \text{Current } i_L(t) \text{ in the inductor and voltage } v_C(t) \text{ across the capacitor are taken as the state variables, both assumed to be initially equal to zero, i.e., } i_L(0) = 0 \text{ and } v_C(0) = 0. \text{ The system is} \]

The propagation delays of the XOR gate, AND gate, and multiplexer (MUX) in the circuit shown in the figure are 4 ns, 2 ns, and 1 ns, respectively. 

If all the inputs \( P \), \( Q \), \( R \), \( S \), and \( T \) are applied simultaneously and held constant, the maximum propagation delay of the circuit is

The switch in the circuit in the figure is in position P for a long time and then moved to position Q at time \( t = 0 \). The value of \( \frac{d v(t)}{dt} \) at \( t = 0^+ \) is 

Consider the circuit shown in the figure. The current \( I \) flowing through the 7 \(\Omega\) resistor between P and Q (rounded off to one decimal place) is . 

(Circuit diagram with resistors and current source)
 

The complete Nyquist plot of the open-loop transfer function \( G(s)H(s) \) of a feedback control system is shown in the figure. If \( G(s)H(s) \) has one zero in the right-half of the s-plane, the number of poles that the closed-loop system will have in the right-half of the s-plane is 

The block diagram of a feedback control system is shown in the figure. 

The transfer function \( \frac{Y(s)}{X(s)} \) of the system is 
 

Consider the circuit with an ideal OPAMP shown in the figure. 
Assuming \( |V_{IN}| \ll |V_{CC}| \) and \( |V_{REF}| \ll |V_{CC}| \), the condition at which \( V_{OUT} \) equals to zero is

For the circuit with an ideal OPAMP shown in the figure, \( V_{REF} \) is fixed. 

If \( V_{OUT} = 1 \, \text{volt} \) for \( V_{IN} = 0.1 \, \text{volt} \) and \( V_{OUT} = 6 \, \text{volt} \) for \( V_{IN} = 1 \, \text{volt} \), where \( V_{OUT} \) is measured across \( R_L \) connected at the output of this OPAMP, the value of \( \frac{R_F}{R_{IN}} \) is:

The energy band diagram of a p-type semiconductor bar of length \( L \) under equilibrium condition (i.e., the Fermi energy level \( E_F \) is constant) is shown in the figure. The valance band \( E_V \) is sloped since doping is non-uniform along the bar. The difference between the energy levels of the valence band at the two edges of the bar is \( \Delta \). 

If the charge of an electron is \( q \), then the magnitude of the electric field developed inside this semiconductor bar is