Radar Engineering and Satellite Communication MCQs

Question 1

The traffic-handling capacity of an Earth station on the up-link depends on

Accepted Answer

all of the above

Answer

its EIRP

Answer

satellite antenna gain

Answer

noise associated with the satellite

Question 2

The different access methods which permit many satellite users to operate in parallel through a single transponder without interfering with each other are

Accepted Answer

all of the above

Answer

frequency division multiple access (FDMA)

Answer

time division multiple access (TDMA)

Answer

code division multiple access (CDMA)

Question 3

A colour television signal having bandwidth of 4.6 MHz is digitised using 10 bits/sample. The digital bit rate used for its transmission with PCM would be kilobits/second.

Accepted Answer

92,000

Answer

920

Answer

23,000

Answer

230

Question 4

Which one of the following statements regarding compandor is FALSE?

Accepted Answer

for weaker signals, it gives a poor ratio of signal strength to quantizing error

Answer

it compresses the higher-amplitude parts of a signal before modulation and expands them back to normal again after demodulation.

Answer

it gives perferential treatment to the weaker parts of the signal

Answer

weaker signals traverse more quantum steps than they would do otherwise and so quantizing error is reduced

Question 5

Regarding TASI which one of the following statements is wrong?

Accepted Answer

the same speaker is reassigned a channel almost instantly when he speaks again even when the circuit is heavily loaded.

Answer

it snatches the channel from a person when he pauses in his speech and may allocate it to another speaker needing it.

Answer

it increase the overall utilization of the transmission channel

Answer

intercontinental callers sometimes confuse the effects of TASI with the effects of satellite delay.

Question 6

Which one of the following statements regarding DR is wrong?

Accepted Answer

though it is more efficient than TASI, it is much slower

Answer

it is a digital form of TASI

Answer

a speaker has to wait (if at all) for only a few milliseconds for reallocation of channel

Answer

it has increased the capacity of satellite channels by a factor of 2.2 or more without degrading speech quality

Question 7

In the context of error detection in satellite transmission, ARQ stands for

Accepted Answer

automatic repeat request

Answer

automatic relay request

Answer

accelerated recovery request

Answer

automatic radiation quenching

Question 8

In a stop-and-wait ARQ systme, the transmitting terminal

Accepted Answer

does not wait for acknowledgement after sending a block

Answer

waits for positive or negative acknowledgement from the receiving terminal after sending a block

Answer

sends another block if positive acknowledgement is received through ACK character

Answer

resends the previous block if negative acknowledgement is received through a NAK character

Question 9

A typical error rate on satellite circuits is one bit error in

Accepted Answer

107

Answer

103

Answer

102

Answer

101?