uhf tacsat /dama multi-service tactics, techniques ... - UHF-Satcom.com

attitude can be measured by the angle the satellite makes
with the object it is orbiting, usually the Earth. Attitude
determines the direction a satellite’s instruments face. The
attitude of a satellite must be constantly maintained; this is
known as attitude control.
aurora Light radiated by ions and atoms in the Earth’s upper
atmosphere, mostly in polar regions.
automatic control An operating mode that allows communications slots within
the waveform to be dynamically assigned to terminals
requiring access to the slots.
automatic
frequency change
Glossary-10
A terminal capability to automatically switch to and operate
on another 5- or 25-kHz DASA or DAMA channel upon
receipt of a FOW directing such a change. This capability
requires the change to be accomplished within 8.96...seconds
for switching to a DASA channel, 90 seconds for switching to
another DAMA channel (5- or 25-kHz), and 90 seconds for
switching from a DASA channel to a DAMA channel. The
90-second switching time from a DASA to a DAMA channel
applies when assigned time on DASA channel expires.
bandwidth A measure of spectrum (frequency) use or capacity. For
instance, a voice transmission by telephone requires a
bandwidth of about 3000 cycles per second (3-kHz). A TV
channel occupies a bandwidth of 6 million cycles per second
(6-MHz) in terrestrial systems. In satellite-based systems, a
larger bandwidth of 17.5- to 72-MHz is used to spread or
“dither” the television signal in order to prevent
interference.
baseband The original band of frequencies produced by a signalinitiating
device such as a microphone or data key prior to
the initial modulation of the carrier.
binary phase-shift
keying
A form of PSK in which the instantaneous phase of the
carrier can be either unchanged or shifted 180 degrees. The
information content of an uncoded BPSK signal is 1 binary
digit (bit) per symbol; therefore, the symbol rate and the
information rate are identical.
bit A single digital unit of information The smallest increment
of digital information. Often referred to as a 1 or 0 in the
binary system. Also referred to as an ‘on’ or ‘off’ when
referring to the mechanical operation of bits in the
computer.
bit error rate The fraction of a sequence of message bits that are in error.
A bit error rate of 10Î6 means that there is an average of
one error per million bits.
bit rate The amount of data being transported, measured relative to
quantity over time in bps; the speed of a digital
transmission, measured in bps.