Electronics and Communication Engineering - Communication Systems

1. 

Consider the following test signal patterns

  1. Ramp
  2. Grill
  3. Grey shades
  4. Sine pulse
  5. Picture line up generating equipment
Which of the above are used in TV studios?

A. All
B. 1, 2 and 3 only
C. 1, 2 and 5 only
D. 2, 3, 4 and 5 only

Answer: Option A

Explanation:

All these are standard test signals used in TV studios.


2. 

If aspect ratio is and number of lines in each frame is 625, the number of picture elements in one frame is

A. x 625
B. (625)2
C. 6252
D. (625)2

Answer: Option B

Explanation:

Since there are 625 lines in one frame, the number of picture elements is .


3. 

Indicate the false statement: If SWR on a transmission line is infinite, the line is terminated in

A. open circuit
B. short circuit
C. pure reactance
D. complex impedance

Answer: Option D

Explanation:

If line is OC or SC or terminated in pure reactance, SWR is 1.


4. 

In TV signals colour burst is used

A. to maintain colour sequence
B. to ensure I and Q phase correctly
C. to synchronise colours
D. for interlacing of horizontal lines

Answer: Option B

Explanation:

Colour burst consists of a short train of about 10 cycles sent to the receiver along with synchronous signals. It ensures I and Q phase correctly.


5. 

The resonant frequency of an RF amplifier is 1 MHz and its bandwidth is 10 kHz. The Q factor will be

A. 10
B. 100
C. 0.01
D. 0.1

Answer: Option B

Explanation:

.


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