Electronics and Communication Engineering - Communication Systems

46.
Which of the following amplifiers is used for impedance matching?
CE
CC
CB
Push pull
Answer: Option
Explanation:

CC connection has low output impedance and is suitable for impedance matching.


47.
Which of the following amplifiers has highest output impedance?
CE
CB
CC
Push pull
Answer: Option
Explanation:

CB connection has high output impedance and is used for radio frequency isolation.


48.
In a superheterodyne receiver, having no RF amplifier, the IF is 455 kHz. The image frequency at 1000 kHz is
1455 kHz
545 kHz
1910 kHz
90 kHz
Answer: Option
Explanation:

Image frequency = 1000 - 455 = 545 kHz.


49.
Audio tapes have two tracks each 2.5 mm wide.
True
False
Answer: Option
Explanation:

Deck is much superior to tape recorder.


50.
Which of the following amplifiers has a voltage gain of less than 1?
CE
CC
CB
CE or CB
Answer: Option
Explanation:

CC circuit has voltage gain of less than 1 and is used for impedance matching.