b. Allotment.
This is a further subdivision of allocation to
services.
The distribution of electromagnetic spectrum channels or
bands to support operations for a type of service within specified
areas or countries and within the United States Government is made to
agencies or departments of the United States Government and United
States nongovernment users.
c. Assignment.
(1) Authority to use a portion of the frequency spectrum is
granted through assignment.
Within the United States military
services, assignments are the result of command processes authorizing
the use of a portion of the spectrum for the operation of
communications-electronics equipments at a state location under
specified conditions, which may include limitations upon the actual
operation of the equipment.
(2) A frequency assignment specifies not only the assigned
(center) frequency but also the size of the spectrum segment
required.
Emission bandwidth describes the size of the spectrum
segment required for a specific frequency assignment.
Thus, a
frequency assignment centered at 40.00 megahertz with an emission
bandwidth of 16 kilohertz would employ frequencies ranging from
39.992 to 40.008 megahertz. The emission bandwidth requirements for
various items of communications-electronics equipment may vary from a
few hertz to several million hertz.
For example, the emission
bandwidth requirements of a radiotelegraph may be on the order of 100
hertz; a radar may require an emission bandwidth of 10 megahertz.
Since the spectrum is portrayed on a logarithmic scale, the capacity
of each segment, in terms of available emission bandwidth, had ten
times the capacity of the next lower frequency segment.
In other
words, the very high frequency band has ten times the capacity of the
high frequency band. By way of further illustrating the significance
of emission bandwidth to spectrum capacity, one television channel
occupies approximately six times the spectrum space required for the
entire commercial amplitude modulation broadcast band.
Figure 2
illustrates the capacity of the radio frequency spectrum in terms of
possible television channels.
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