When the transmitter wishes to send data, it first places the line in a sp

in a space level (i.e. the complement of a mark) for one element period. This element is called the start bit and has a duration of T seconds. The transmitter then sends the character, l bit at a time, by placing each successive bit on the line for a duration of T seconds, until all bits have been transmitted. Then a single parity bit is calculated by the transmitter and sent after the data bits. Finally, the transmitter sends a stop bit at a mark level (i.e. the same level as the idle state) for one or two bit periods. Now the transmitter may send another character whenever it wishes.

At the receiving end of an asynchronous serial data link, the receiver continually monitors the line looking for a start bit. Once the start bit has been detected, the receiver waits until the end of the start bit and then samples the next N bits at their centers, using a clock generated locally by the receiver. As each incoming bit is sampled, it is used to construct a new character. When the received character has been assembled, its parity is calculated and compared with the received parity bit following the character. If they are not equal, a parity error flag is set to indicate a transmission error.

(1).When the transmitter wishes to send data, it first sends().

A.a character at the same time

B.a character to the line

C.the start bit

D.a mark level to the line

(2).The transmitter then send the character, for a duration of T seconds().

A.each bit

B.all bits

C.successive bits

D.a start bit and a character

(3).Finally, the transmitter sends a stop bit at the same level as for one or two bit periods().

A.the space level

B.the mark level

C.the complement of the mark level

D.another character

(4).At the receiving end of an asynchronous serial data link, the receiver().

A.does not monitor the start bit

B.waits until the beginning of the start bit

C.samples the start bit at its center

D.generates a local clock

(5).When the received character has been assembled, its parity().

A.is set to indicate a transmission error

B.is compared with the received character

C.is an error flag

D.may be equal to the received parity

ring transmitter maintenance periods when the broadcast will be made on the two frequencies ______.

A.at the same time

B.exclusively

C.within the same period

D.consecutively

A. prevent the leakage of external fiber emissions

B. provide the optical network with the highest level of security possible

C. assure an even distribution of 1‘s and 0‘s for extended transmitter life

D. assure an adequate number of transitions for clock recovery at the receiver

E. prevent the receiver from assuming AIS inadvertently when all 0‘s are received

Which of the following should be noted when performing hardware loop on optical interface through fiber？()

A.Never look straight at output optical interface or tail fiber end surface that connects with it.

B. First you must disable laser output to avoid too strong output power burning down tail fiber end face.

C. Use an optical power meter to measure input interface power to avoid receiver burning down due to overload.

D. If there are no attenuators, loosen the receiver and tighten the transmitter to prevent optical input from overloading.

神经递质(nervous transmitter)

Please be advised that my radio transmitter broke down and needs________.

A.repair

B.reapiring

C.to repair

D.be reapried

lied to any future RDF bearings is listed against the ______．

A.true bearing of the transmitter

B.relative bearing of the transmitter

C.heading of the vessel

D.time of reception

A.Site表中的EquipmeNt项；

B.TRANSmitteR表中的MAiNpRopogAtioNmodelS项

C.Site表中的CommeNtS项；

D.TRANSmitteR表中的MAiNReSolutioN项。

A) demonstrator

B) exhibitor

C) monitor

D)transmitter

orificeplate、transmitter分别是（)和（)两种仪表的英语表示法。