Wegener UNITY4000, Instruction Manual

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C-1 UTY4000-003
Appendix C
Glossary of Terms
AMBER - An LED with the red and green both “On.”
ASIC - Application-specific Integrated Circuit: A general term for any highly integrated
circuit (in a single package that historically very complex operations solders to a printed-
circuit-board) implementing.
BLINK - An LED which is ON for 250 mS and OFF for 250 mS, with the pattern
continuing for some time, is said to “Blink.” See Table 3-1, page 3-2. Also, see “Flash”
and “Flutter.”
COMPEL™ - Wegener's patented satellite network control system. This is a system
which features a control data stream embedded along with the payload services, where
a single central control site may control all aspects of network operation: database
management, program selection and setup by site, grouping of sites, scheduling, etc.
DAC - Digital-to-Analog Converter. A device that converts a sequence of numbers
representing signal amplitudes in electronic binary format to actual analog signals.
EEPROM - Electrically-Erasable Programmable Read-Only Memory. This acronym is
used to describe any non-volatile memory device which can be read- or written-to a
nearly unlimited number of times, but which retains its last written data when power is
turned off.
FEC - Concatenated FEC: Forward Error Correction. A method of mapping digital data
for transmission over a noisy, error-creating medium, and then un-mapping it, such that
error-reduction is achieved. This allows for lower-power (but wider bandwidth) carriers
to be used than would otherwise be required on a satellite link. Concatenated FEC
means that a bit-level convolutional FEC is embedded "inside" a byte or frame-level
Reed-Solomon FEC within the transmission path. This is done to create a far more
powerful error-reduction system than either type of FEC alone could provide.
FLASH - An LED which is ON for 100 mS and OFF for 100 mS, with the pattern
continuing for some time, is said to “Flash.” See Table 3-1, page 3-2. Also, see “Blink”
and “Flutter.”
FLUTTER - An LED which is ON for 50 mS and OFF for 50 mS, with the pattern
continuing for some time, is said to “Flutter.” See Table 3-1, page 3-2. Also, see “Blink”
and “Flash.”
MCPC - Multiple-Channel-Per-Carrier. Means that one or more services or programs
are present on a particular radio-frequency carrier.