15. Theoretically, the bandwidth of a composite frequency-division-multiplex signal may be expanded by the
equipment to accommodate any number of channels through the process of
a. varying the length of each time frame.
b. adding pulses to the time frame.
c. keying the signal at a fast rate.
d. translating channel frequencies.
16. Carrier systems generally are required to carry many parallel channels of information. In most military
carrier systems, the channel information consists of
a. voice or teletypewriter messages.
b. telemetry signals.
c. on-tone, off-tone messages.
d. guided missile command signals.
17. An area communication system makes extensive use of carrier equipment. The primary function of a
carrier channel in such a system is to serve as
a. trunk lines between unit switchboards.
b. trunk lines between air defense stations.
c. local lines between switchboards and telephones.
d. local lines for control of guided missile firing operations.
18. The equipment in a fixed-plant carrier telephone system is similar to that used in a
a. mobile system.
b. portable system.
c. tactical system.
d. commercial system.
19. One of the characteristics of fixed-plant carrier equipment is its
a. small size.
b. light weight.
c. low power consumption.
d. need to be protected against weather.