Electronics and Communication Engineering - Communication Systems

26.
In cellular telephone each cell is designed to handle
45 two way communications
90 two way communications
45 one way communications
180 two way communications
Answer: Option
Explanation:

Each cell is designed for 45 two way conversations.


27.
A UPS contains
rectifier
inverter
either rectifier or inverter
both rectifier and inverter
Answer: Option
Explanation:

Rectifier is needed to charge the battery. Inverter is needed to feed the loads during power failure.


28.
A transmitter power of 10 W is increased by 30 dB. The effective radiated power is
100 W
1000 W
10000 W
100000 W
Answer: Option
Explanation:

or P = 10000 W.


29.
It is desired to couple a coaxial line to a two parallel wire line. It is best to use
quarter wave transformer
balun
slotted line
directional coupler
Answer: Option
Explanation:

Balun gives 4 : 1 impedance transformation and is suited for coupling a coaxial line to two wire line.


30.
24 telephone channels are frequency division multiplexed using an SSB modulation. Assuming 3 kHz per channel, the required band width is
8 kHz
27 kHz
21 kHz
72 kHz
Answer: Option
Explanation:

Since SSB modulation is used, bandwidth = 24 x 3 = 72 kHz.