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

participate in a class broadcast from another location.
distributed control An operating mode in which a terminal's access to a
communications slot is preassigned (both time-slot and
frame format).
Doppler shift An apparent shift in the frequency of a wave. For example,
when someone is listening to the sound of an ambulance
siren, and that person is staying still but the ambulance is
driving by, the person hears a change in pitch of the
ambulance siren. That change in pitch is caused by the
“Doppler effect”. The frequency of a sound wave determines
the pitch, so the distance of the source of the sound from the
observer of that sound determines the amount that the
frequency seems to have shifted, known as the Doppler shift.
downlink The satellite-to-earth half of a 2-way telecommunications
satellite link. Often used to describe the receive dish end of
the link.
downlink
acquisition
Glossary-14
Condition during initial acquisition of the waveform, when
the terminal or a non-controlling CC receives a correct FOW
burst.
dual spin Spacecraft design whereby the main body of the satellite is
spun to provide altitude stabilization, and the antenna
assembly is despun by means of a motor and bearing system
in order to continually direct the antenna earthward. This
dual-spin configuration thus serves to create a spinstabilized
satellite.
eccentricity The measure of how circular a satellite’s orbit is. For a
perfectly circular orbit the eccentricity is zero; elliptical
orbits have eccentricities between zero and one. The higher
the eccentricity, the more “squashed” the orbit is.
effective isotropic
radiated power
This term describes the strength of the signal leaving the
satellite antenna or the transmitting earth station antenna,
and is used in determining the carrier/noise (C/N) and
signal/noise (S/N). The transmit power value in units of
decibels relative to 1 watt is expressed by the product of the
transponder output power and the gain of the satellite
transmit antenna.
encryption To encode data so as to render a document unreadable by all
except those who are authorized to have access to it.
Encryption is accomplished by scrambling the bits,
characters, words, or phrases in the original message.
energy per bit The average signal energy contained in a binary digit.
even link test timeslot
A link test time-slot used to perform dedicated ranging
measurements when the receive frame count is even.
field A specific portion of a burst or message.
fill bits Fill bits are used to complete the last interleaver block and
must be zero.