Chapter 26: Satellite Multiple Accessing Arrangements - Review Notes

Reviewer and summary notes of the important concepts and formulas in Chapter 26 of the book "Introduction to Electronics Communications" by Wayne Tomasi.

Chapter 26: Satellite Multiple Accessing Arrangements

This is the summary notes of the important terms and concepts in Chapter 26 of the book "Electronic Communications System" by Wayne Tomasi. The notes are properly synchronized and concise for much better understanding of the book. Make sure to familiarize this review notes to increase the chance of passing the ECE Board Exam.

CHAPTER 26

SATELLITE MULTIPLE ACCESSING ARRANGEMENTS

Items

Definitions

Terms

1

Also called as Multiple Destination, It implies that more than one user has access to one or more radio channels within a satellite communications channel.

Multiple Accessing Arrangement:

·         Frequency-division multiple accessing (FDMA)

·         Time-division multiple accessing (TDMA)

·         Code-division multiple accessing (CDMA)

Multiple Accessing

2

A given number of the available voice-band channels from each earth station are assigned a dedicated destination.

Pre-assignment (dedicated)

3

Voice channels are assigned on an as-needed basis.

Demand Assignment

4

The method of assigning adjacent channels different electromagnetic polarizations and is possible by using orthogonal polarization and spacing adjacent channels 20 MHz apart.

Frequency Reuse

5

Eskimo word meaning “little brother”.

Anik

6

Domestic Satellites operated by Telsat Canada.

Anik-E communications Satellite

7

A method of multiple accessing where a given RF bandwidth is divided into smaller frequency bands.

FDMA

8

Multiple channels per carrier formats assigned and remain fixed for a long Period of time.

Fixed-Assignment, Multiple

Access (FAMA)

9

Assigning carrier frequency on temporary basis using a statistical assignment process.

Demand-Assignment

Multiple Access

10

An acronym for Single-channel-per-carrier PCM multiple Access Demand-assignment Equipment.

SPADE

11

Stands for Single-Carrier-Per-Channel.

SCPC

12

A time division-multiplexed transmission that is frequency division multiplexed.

Common Signaling Channel

(CSC)

13

The predominant Multiple-access method of time division multiplexing digitally modulated carriers between participating earth stations within a satellite network through a common satellite transponder.

TDMA

14

An RF-to-RF repeater that simply receives the earth station transmissions, amplifies them, and then retransmits them in a downlink beam that is received by all other participating station.

Transponder

15

It is where transmissions from all earth stations are synchronized.

Reference Burst

16

It is where all receiving stations recover a frequency and phase coherent carrier for PSK demodulation.

Carrier Recovery Sequence

(CRS)

17

An acronym for, Conference of European Postal and Telecommunications Administrations, is commonly used TDMA frame format for digital satellite system.

CEPT

18

Sometimes referred to as Spread-Spectrum Multiple entire allocated bandwidth Access, the transmissions can spread throughout.

Code-Division Multiple Access

CDMA)

19

A unique binary word that each earth station’s transmissions are encoded.

Chip Code

20

It compares two signals and recover the original data.

Correlator

21

It assigns an individual terrestrial channel (TC) to a particular satellite channel (SC) for the duration of the call.

Digital non interpolated Interface

22

It assigns a terrestrial channel to a satellite channel only when speech energy is present on the TC.

Digital Speech Interpolated Interface

23

A form of analog channel compression that has been used for sub oceanic cables for many years.

Time-Assignment Speech Interpolation

(TASI)

24

The art or science of plotting, ascertaining or directing the course of movements, in other words, knowing where you are and being able to find your way around.

Navigation

25

It is the most ancient and rudimentary method of navigation and simply continuing to travel about until you reach your destination, assuming of course that you have one.

Wandering

26

Earliest effective means of navigation wherein direction and distance are determined from precisely timed sightings of celestial bodies, including the stars and moon.

Celestial Navigation

27

Method of navigation by means of fixing a position and direction with respect to familiar, significant landmarks such as railroad tracks, water towers, barns, mountains and bodies of water.

Piloting

28

A navigation technique that determines position by extrapolating a series of measured velocity increments.

Dead Reckoning

29

The term derived from the word “deduced” and not necessarily from the fate of the people who used the technique.

Dead

30

He used dead reckoning successfully in 1927 during his historic 33-hour transatlantic journey.

Charles Lindbergh

31

She attempted to make the first around-the-world in 1937 using the dead reckoning technique.

Amelia Earhart

32

Navigation technique wherein the position is determined by measuring the travel time of an electromagnetic wave as it moves from a transmitter to a receiver.

Radio Navigation

33

A radio Navigation system for terrestrial surface broadcast.

Decca

34

Radio Navigation system that provides global coverage and terrestrial surface broadcast.

Omega

35

Also a terrestrial surface broadcast.

LORAN

36

Low-orbit satellite broadcast that provides global coverage.

Navy Transit GPS

37

Medium-orbit satellite broadcast also provides global coverage.

Navstar GPS

38

Means of radio navigation in which receivers acquire Coded signals from two pairs of high-powered, land based transmitters whose locations are precisely known.

LORAN

39

An acronym for Navigation System with Time and Ranging.

Navstar

40

An abbreviation for Global Positioning System.

Two levels of service or accuracy:

·         Standard Positioning Service

·         Precise Positioning Service

GPS

41

A satellite-based open navigation system which simply means that it is available to anyone equipped with a GPS receiver.

Consists of three segments:

·         a space segment

·         a ground control segment

·         user segment

Navstar GPS

42

It was when the Navstar declared as fully operational by the U.S. Air Force Space Command.

April 27, 1995

43

It was completed in 1994 and is maintained by the United States Air Force.

Navstar Satellite System

44

A positioning and timing service that is available to all GPS users on a continuous, worldwide basis with no direct change.

Standard Positioning

Service

45

Sometimes called Space Segment, consists of 24operational satellites revolving around Earth in six orbital planes approximately 60° apart with four satellites in each plane.

Satellite Segment

46

It produces highly accurate timing signals for satellites.

Cesium Atomic Clock

47

A unique integer number that is used to encrypt the signal from that satellite.

Pseudorandom Noise

(PRN)

Code Number

48

A term associated with a table showing the position of a heavenly body on a number dates in a regular sequence, in essence, an astronomical almanac.

Ephemeris

49

Error in the receiver’s clock which affects the accuracy of the time-difference measurement.

Clock Bias Error

50

The Navstar control segment.

It consists of :

·         Fixed-location ground based monitor stations

·         Master Control Station

·         uplink transmitter

Operational Control

System

51

It makes standard GPS more accurate. It works by cancelling out most of the natural and man-made errors that creep into normal GPS measurements.

Differential GPS

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