歷年特許公認(rèn)會計(jì)師考試模擬試題

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ALLOCATION OF FREQUENCIES IN THE RADIO SPECTRUM
    In the United States the National Telecommunications and Information Administration (NTIA) has responsibility for assigning each portion of the
    radio spectrum (9 kHz to 300 GHz) for different uses. These assignments must be compatible with the rules of the International Telecommunications
    Union (ITU), to which the United States is bound by treaty. The current assignments are given in a wall chart (Reference 1) and may also be found
    on the NTIA web site (Reference 2). The list below summarizes the broad features of the spectrum allocation, with particular attention to those sections
    of scientific interest. The references should be consulted for details of the allocations in the frequency bands listed here, which in some cases are quite
    complex.
    REFERENCES
    1. United States Frequency Allocations, 1996 Spectrum Wall Chart, Stock No. 003-000-00652-2, U. S. Government Printing Office, P. O. Box
    371954, Pittsburgh, PA 15250-7954.
    2. http://www.ntia.doc.gov/osmhome/allochrt.html
    Frequency range Allocation
    9 - 19.95 kHz Maritime communication, navigation
    19.95 - 20.05 kHz Standard frequency and time signal (also at 60 kHz and 2.5, 5, 10, 15, 20, 25 MHz)
    20.05 - 535 kHz Maritime and aeronautical communication, navigation
    535 - 1605 kHz AM radio broadcasting
    1605 - 3500 kHz Mobile communication and navigation, amateur radio (1800-1900 kHz)
    3.5 - 4.0 MHz Amateur radio
    4.0 - 5.95 MHz Mobile communication
    5.95 - 13.36 MHz Mobile communication, amateur, short-wave broadcasting
    13.36 - 13.41 MHz Radioastronomy
    13.41 - 25.55 MHz Mobile communication, amateur, short-wave broadcasting
    25.55 - 25.67 MHz Radioastronomy
    25.67 - 37.5 MHz Mobile communication, amateur, short-wave broadcasting
    37.5 -38.25 MHz Radioastronomy
    38.25 - 50.0 MHz Mobile communication
    50.0 - 54.0 MHz Amateur
    54.0 - 72.0 MHz TV channels 2-4
    72.0 - 73.0 MHz Mobile communication
    73.0 - 74.6 MHz Radioastronomy
    74.6 - 76.0 MHz Mobile communication
    76.0 - 88.0 MHz TV channels 5-6
    88.0 - 108.0 MHz FM radio broadcasting
    108.0 - 118.0 MHz Aeronautical navigation
    118.0 - 174.0 MHz Mobile communication, space research, meteorological satellites
    174.0 - 216.0 MHz TV channels 7-13
    216.0 - 400.05 MHz Mobile communication
    400.05 - 400.15 MHz Standard frequency and time satellite (also 20 and 25 GHz)
    400.15 - 406.1 MHz Meteorological aids (radiosonde)
    406.1 - 410.0 MHz Radioastronomy
    410.0 - 470.0 MHz Mobile communication, amateur
    470.0 - 512.0 MHz TV channels 14-20
    512.0 - 608.0 MHz TV channels 21-36
    608.0 - 614.0 MHz Radioastronomy
    614.0 - 806.0 MHz TV channels 38-69
    806 -1400 MHz Mobile communication, navigation
    1400 - 1427 MHz Radioastronomy, space research
    1427 - 1660 MHz Various navigation and satellite applications
    1660 - 1710 MHz Radioastronomy, space research, meteorology