169. Regarding TASI which one of the following statements is wrong?
A. it snatches the channel from a person when he pauses in his speech and may allocate it to another speaker needing it.
B.the same speaker is reassigned a channel almost instantly when he speaks again even when the circuit is heavily loaded.
C. it increase the overall utilization of the transmission channel
D. intercontinental callers sometimes confuse the effects of TASI with the effects of satellite delay.
170. Which one of the following statements regarding DR is wrong?
A. it is a digital form of TASI
B. though it is more efficient than TASI, it is much slower
C.a speaker has to wait (if at all) for only a few milliseconds for reallocation of channel
D.it has increased the capacity of satellite channels by a factor of 2.2 or more without degrading speech quality
171. In the context of error detection in satellite transmission, ARQ stands for
A. automatic repeat request
B. automatic relay request
C. accelerated recovery request
D. automatic radiation quenching
172. In a stop-and-wait ARQ systme, the transmitting terminal
A. waits for positive or negative acknowledgement from the receiving terminal after sending a block
B.sends another block if positive acknowledgement is received through ACK character
C.resends the previous block if negative acknowledgement is received through a NAK character
D.does not wait for acknowledgement after sending a block
173. A typical error rate on satellite circuits is one bit error in
174. The most effective antijamming technique is
A. frequency hopping
B. spread-spectrum modulation
C. key leverage
D. once-only key
175. The present total cost per watt of power generation in geosynchronous orbit is nearly Rs.
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