This is a Question Papers of Mumbai University for B.Sc.IT Student of Semester - I [Electronic and Communication Technology] (Revised Course). [Year - January / 2017] . . .Solution Set of this Paper is Coming soon..

1. E l e c t r o n i c s a n d C o m m u n i c a t i o n s T e c h n o l o g y
Q u e s t i o n P a p e r ( J a n u a r y – 2 0 1 7 ) [ R e v i s e d C o u r s e ]
1 | Page
M u m b a i B . S c . I T S t u d y
F a c e b o o k | T w i t t e r | I n s t a g r a m | G o o g l e + | Y o u T u b e
– Kamal T.
Time: 3 Hours Total Marks: 100
N.B.: (1) All Questions from 1 to 7 are Compulsory.
(2) Figure To right indicate the marks.
Q.1 Attempt Any Two From The Following: (10 Marks)
(A) Explain the formation of P-Type Semiconductor with necessary diagram. (5)
(B) Draw a neat Labelled Block Diagram of an Oscillator. (5)
(C) Explain working of Transistor as a Switch. (5)
(D) Define AM and draw the Waveforms. (5)
(E) State the Sampling Theorem and explain it. (5)
Q.2 Attempt Any Three From The Following: (15 Marks)
(A) Explain the working of P-N Junction diode with necessary diagrams. (5)
(B) With the help of Circuit Diagram explain the working of Half Rectifier with necessary
Wave-Forms.
(5)
(C) Explain the output characteristics of P-N-P Transistor in CE Configuration. (5)
(D) The turns ratio of a transformer uses in a bridge rectifier is 100:1. The primary is
connected to a 230 VRMS mains supply. Assuming diode voltage drop to be 0.5 V, find
the de voltage across the load resistance & the PIV of each diode. Also find the load
current if a load resistance of 100 Ω is used.
(5)
(E) When the emitter current of a transistor is changed by 1.1 mA its collector current
changes by 0.97 mA. Calculate its common base current gain(𝛽) and common emitter
current gain(𝛼).
(5)
Q.3 Attempt Any Three From The Following: (15 Marks)
(A) Explain the working of single stage CE amplifier. Also discuss its frequency response
curve.
(5)
(B) With the help of circuit diagram explain the working of Multistage Amplifier. Derive an
expression for its gain decibel.
(5)
(C) Explain working of RC coupled amplifier with circuit diagram discuss its frequency
response curve.
(5)
(D) Explain the need of biasing a transistor. Explain the fixed biased method of biasing. (5)
(E) Explain how to plot the load line of CE amplifier. What is Q-point? (5)

2. E l e c t r o n i c s a n d C o m m u n i c a t i o n s T e c h n o l o g y
Q u e s t i o n P a p e r ( J a n u a r y – 2 0 1 7 ) [ R e v i s e d C o u r s e ]
2 | Page
M u m b a i B . S c . I T S t u d y
F a c e b o o k | T w i t t e r | I n s t a g r a m | G o o g l e + | Y o u T u b e
– Kamal T.
Q.4 Attempt Any Three From The Following: (15 Marks)
(A) Explain the need of tank circuit in an oscillator. Explain the RC Tank circuit. (5)
(B) Explain the working of RC Phase Shift Oscillator with its Circuit Diagram. (5)
(C) Explain the Block Diagram of IC555. (5)
(D) An astable multivibrator using IC555 has 𝑅 𝐴 = 470Ω, 𝑅 𝐵 = 2𝑘Ω and 𝐶 =
0.0076𝑢𝐹. Calculate charging and discharging time constant duty cycle and output
frequency.
(5)
(E) A Colpitt’s Oscillator uses following components in its turned 𝐶1 = 1500𝑝𝐹, 𝐶2 =
800𝑝𝐹, 𝐿 = 200𝜇𝐻. Calculate the frequency of the Oscillator.
(5)
Q.5 Attempt Any Three From The Following: (15 Marks)
(A) With the help of Circuit Diagram explain the working of Balanced Modulator. (5)
(B) Explain the Block Diagram of the Basic Communication System. (5)
(C) Explain filter method for side band suppression with block diagram. (5)
(D) An audio signal is given by 𝐸 𝑚 = 100 sin(3140)𝑡. It Amplitude Modulates a carrier
frequency of carrier, Frequency of Modulating Signal, Amplitude of Side Band
Components & their Frequency.
(5)
(E) Explain the Low Level Modulator. (5)
Q.6 Attempt Any Three From The Following: (15 Marks)
(A) With help of Block Diagram explain the Television Transmitter. (5)
(B) Explain TRF Receiver with the Block Diagram. (5)
(C) Compare PM and AM Systems. (5)
(D) Explain Typical Pre-Emphasis & De-Emphasis Circuit with their characteristics. (5)
(E) Explain PPM Generator with Waveforms. (5)
Q.7 Attempt Any Three From The Following: (15 Marks)
(A) Explain Amplitude Shift Keying. (5)
(B) Explain types of Optical Fiber. (5)
(C) Explain the Optional Links in detail. (5)
(D) Explain the construction and working of LED. (5)
(E) Write a note on Ray Model. (5)