10. One of the difficult technical problems in time-division multiplex is to maintain synchronization of the
receiving terminal by means of the incoming signal. Synchronization is necessary, because in TDM
a. the sampling occurs at an audible rate.
b. each channel uses a highly selective filter to separate the signal frequencies.
c. each received pulse sample must be selected in sequence and placed into its appropriate channel.
d. the pulses sample the various channels without regard to a sequential time pattern.
11. The function of the equalizer in a telephone carrier terminal is to
a. level out all received signals to the same strength.
b. raise the received line signals to the required levels.
c. attenuate the highest signal frequencies and amplify the lowest.
d. transmit varying signal levels at different frequencies to compensate for line losses.
12. The function of a line repeater in a carrier system is to
a. prevent interchannel interference.
b. prevent overloading of the receiving channels.
c. compensate for loss in each unit length of line.
d. automatically compensate for changes in output level from the transmitting terminal.
13. Many channels of telegraph carrier can be included within one voice band because
a. each channel of telegraph carrier occupies a relatively narrow frequency band.
b. the low line level prevents overloading of channel amplifiers.
c. each channel operates on a separate carrier frequency.
d. telegraph carrier channels require no equalization.
14. Four types of signals that are to be sent over a carrier system include: teletypewriter, voice, facsimile, and
data. The signal requiring the widest bandwidth during transmission is
a. voice.
c. facsimile.
b. data.
d. teletypewriter.
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