1
GATE ECE 1995
Subjective
+10
-0
A ROM is to be used to implement the Boolean functions given below:
$${F_1}$$$$(A,\,B,\,C,\,D) = ABCD + \bar A\,\overline B \,\bar C\,\bar D$$
$${F_2}(A,\,B,\,C,\,D) = (A + B)(\bar A\, + \overline B + C)$$
$${F_3}(A,\,B,\,C,\,D) = \sum {13,15 + \sum {3,5} } $$
$${F_1}$$$$(A,\,B,\,C,\,D) = ABCD + \bar A\,\overline B \,\bar C\,\bar D$$
$${F_2}(A,\,B,\,C,\,D) = (A + B)(\bar A\, + \overline B + C)$$
$${F_3}(A,\,B,\,C,\,D) = \sum {13,15 + \sum {3,5} } $$
(a) What is the minimum size of the ROM required?
(b) Determine the data in each location of the ROM.
2
GATE ECE 1994
Subjective
+10
-0
A Boolean function, F , given as sum of product (SOP) terms as F= $$\sum {} $$m(3,4,5,6) with A,B, and C as inputs. The function, F, can be expreeed on the Karnaugh's map shown below.
(1) What will be the minimized SOP expression for F?
(2) Implement this function on an 8 : 1 MUX.
3
GATE ECE 1993
Subjective
+10
-0
Signals A,B,C,D and $$\overline D $$ are available. Using a single 8 - to - 1 multiplexer and no other gate, implement the Boolean function.
$$f(A,B,C,D) = B.C + A.B.\bar D + \bar A.\bar C.\bar D$$
$$f(A,B,C,D) = B.C + A.B.\bar D + \bar A.\bar C.\bar D$$
4
GATE ECE 1989
Subjective
+10
-0
A chemical reactor has three sensors indicating the following conditions:-
(1) Pressure (P) is low or high'
(2) Temperature (T) is low or high' and
(3) Liquid level (L) is low or high.
(1) Pressure (P) is low or high'
(2) Temperature (T) is low or high' and
(3) Liquid level (L) is low or high.
its has two controls - Heater (H) which is either on or off and inlet value (V) which is open or close. The controls are operated as per Table.
(a) Using the convertion High =1, Low = 0, On=1, Off=0, Open=1 and Closed=0, draw the Karnaugh maps for H and V.
(b) Obtain the minimal product of sums expressions for H and V.
(c) Realize the logic for H and V using two 4-input multiplexers with T and L as control inputs. Used T as MSB.
Questions Asked from Combinational Circuits (Marks 10)
Number in Brackets after Paper Indicates No. of Questions
GATE ECE Subjects
Network Theory
Control Systems
Electronic Devices and VLSI
Analog Circuits
Digital Circuits
Microprocessors
Signals and Systems
Representation of Continuous Time Signal Fourier Series Discrete Time Signal Fourier Series Fourier Transform Discrete Time Signal Z Transform Continuous Time Linear Invariant System Transmission of Signal Through Continuous Time LTI Systems Discrete Time Linear Time Invariant Systems Sampling Continuous Time Signal Laplace Transform Discrete Fourier Transform and Fast Fourier Transform Transmission of Signal Through Discrete Time Lti Systems Miscellaneous Fourier Transform
Communications
Electromagnetics
General Aptitude