DipIETE – ET (OLD SCHEME)
Code: DE18 Subject:
TELEVISION ENGINEERING
Time: 3 Hours Max. Marks: 100
NOTE: There are 9 Questions in all.
· Question 1 is compulsory and
carries 20 marks. Answer to Q.1 must be written in the space provided for it in
the answer book supplied and nowhere else.
· Out of the remaining EIGHT
Questions, answer any FIVE Questions. Each question carries 16 marks.
· Any required data not explicitly
given, may be suitably assumed and stated.
Q.1 Choose
the correct or the best alternative in the following: (2
10)
a. The channel bandwidth as per
CCIR-B 625 line system used in
(A) 6.0
MHz (B)
7.0 MHz
(C) 5.0 MHz (D) 8.0 MHz
b. The colour burst is placed at ________.
(A)
the back porch of the horizontal sync
pulse
(B)
the front porch of the horizontal
sync pulse
(C) during the vertical blanking period
(D) during
equalizing pulses
c. The colour sub-carrier frequency used in the PAL – B colour TV system is _______.
(A) 3.58 MHz (B) 33.4 MHz
(C) 4.43 MHz (D) 38.9 MHz
d. The camera tube based on the photo-emission principle is _________.
(A)
Image Orthicon (B) Vidicon
(C) Plumbicon (D) CCD
e. Interlacing is used in television to ________.
(A) produce illusion of motion
(B) ensure that all the lines on the screen are scanned
(C) simplify the vertical sync pulse train
(D) avoid flicker
f. In a TV receiver, the colour killer _________.
(A)
cuts
off the chroma stage during monochrome reception
(B) ensures that no colour is transmitted to
monochrome TV receiver
(C) prevents colour overloading
(D) makes sure that the colour burst is mistaken
for pulses, by cutting off reception during the back porch
g. The video voltage applied to the picture tube of a TV receiver is fed ________.
(A) between grid and ground (B) to the yoke
(C) to the anode (D)
between grid and cathode
h. According to CCIR-B 625 line system used in
(A) 61 - 68 MHz (B) 174-181 MHz
(C) 54 - 61 MHz (D)
47 - 54 MHz
i. The EHT voltage in a TV receiver is measured with_________.
(A) multimeter (B)
pattern Generator
(C) HV Probe (D) sweep
Generator
j. Automatic Brightness control forms a part of which of the following circuit?
(A) Video Amplifier (B) Audio Amplifier
(C) Vertical Oscillator (D) Horizontal Oscillator
Answer any FIVE Questions out
of EIGHT Questions.
Each question carries 16
marks.
Q.2 a. Explain in brief “Interlaced scanning” used
in television systems. (4)
b. Derive an
expression for the highest modulating frequency in a television system and show
that it is nearly 5 MHz in the 625 line monochrome system. (6)
c. What are post equalizing and pre-equalizing
pulses? (6)
Q.3 a. Explain with the help of suitable sketches,
how video signal is developed in a Vidicon camera tube? (8)
b. Describe the
constructional details and working of a PIL colour picture tube. (8)
Q.4 a. Explain with a block diagram how colour difference signals are generated? (8)
b. What is vestigial sideband transmission and why it is used for transmission
of TV picture signals? (8)
Q.5 a. Explain
the working of a monochrome TV receiver with a neat block diagram. (10)
b. Explain the operation of RF Tuner with a neat block diagram. (6)
Q.6 a. Describe with a block diagram, how
various patterns are generated in a video patterns generator? Explain typical
applications of this instrument for testing and aligning a TV receiver. (11)
b. Draw a neat sketch of a composite video
signal and explain various terms in it. (5)
Q.7 a. Sketch Turnstile Array antenna and explain
the function of various elements in it. (6)
b. What are the advantages of AGC in a TV
receiver? Explain with a neat circuit the working of keyed AGC using
transistor. (10)
Q.8 a. Explain frequency
interleaving technique used in colour television transmission system. (8)
b. Explain the
block diagram of PAL - D Encoder. (8)
Q.9 a. Explain positive and negative modulation and
compare them. (8)
b. Explain with a
neat block diagram the function of monochrome TV transmitter. (8)