SECTION 1 : BASIC PRINCIPLES OF COMMUNICATIONS ENGINEERING

J. AMPOLOQUIO

Electronic

Communication

Transmission, reception, and processing of information between two

or more locations using electronic circuits

Allocation Entry in the table of frequency allocations of a given frequency

band

Allotment Entry of designated frequency channel in the agreed plan for the

use of two or more nations

Assignment Authorization given by a nation for a radio station to use frequency

channel under specified conditions

Hans Christian

Oersted

Discovered relation between electricity and magnetism in 1820

Andre Marie Ampere Observed the phenomenon of electromagnetic induction;

hypothesized the existence of magnetic field around a current

carrying conductor (1821)

Michael Faraday Discovered electromagnetic induction; reverse of Oersteds

discovery (1822)

Joseph Henry Demonstrated telecommand, wire telegraphy was born

Samuel Morse Exploited Henrys invention commercially

James Clerk Maxwell Hypothesized the existence of EM waves (1866)

Heinrich Hertz Radio waves (1886)

Guglielmo Marconi Developed the first wireless telegraph; used spark gap transmitter

(1896)

Major Edwin

Armstrong

First successful FM radio system (1900)

Reginald Aubrey

Fessenden

Invented AM (1936)

Wired Medium The signal is confined within the proximity of the channel; bounded

or guided

Wireless Medium Signal is not subjected to limits; unbounded or unguided

White Noise Noise that has equal amount of energy per octave

Brown Noise Similar to pink noise but with a power density decrease of 6dB per

octave

Blue Noise Doubles the amount of energy as you go up 1 octave

Purple Noise/ Violet

Noise

Differentiated white noise; increases 6dB per octave

Orange Noise Quasi stationary noise with a finite power spectrum with a finite

number of small bands of zero energy dispersed throughout a

continuous spectrum

Black Noise Noise that has frequency spectrum of zero power level over all

frequencies except for a few narrowband or spikes

A3E Double sideband full carrier

H3E Single sideband full carrier

J3E Single sideband suppressed carrier

R3E Single sideband reduced carrier

C3F Vestigial sideband modulation

Amplitude Shift

Keying

On off Keying

CP FSK Continuous Phase FSK

Standard

Oscilloscope

Used to display the amplitude versus time representation of the

input signal

Frequency Number of times a particular phenomenon occurs in a given period

of time

Wavelength Distance between two points of similar cycles of periodic wave

Period Time required for one cycle of a repetitive system

Spectrum Analyzer Used to display amplitude versus frequency representation of the

input signal

Doppler Effect A perceived change in the frequency of a wave as the distance

between source and observer changes

Absolute Bandwidth f2 f1, where the spectrum is zero outside the interval along positive

frequency axis

-3dB Bandwidth or

Half Power Bandwidth

f2 f1, where for frequency inside f1

Designation 2nd Symbol : type of transmission

3rd Symbol : supplementary character

Simplex Only in one direction

Half Duplex Both direction but not the same time

Full Duplex Two way simultaneous

Full/Full Duplex Transmit and receive simultaneously but not necessary between

same two locations

Two-wire Those that carry information signal in both directions over the same

path

4-wire Over separable paths

FDM Frequency Division Multiplexing; unique band of frequency on each

channel on continuous time basis

TDM Time Division Multiplexing; each channel is allotted fixed time slot

occupying the entire wideband frequency

STDM Statistical TDM

WDM Wavelength Division Multiplexing; sending information signal that

occupy same frequency at the same time

Narrowband Single channel (64Kbps) or some of 64Kbps channels (N x 64Kbps)

but less than wideband

Wideband Multichannel capacity; 1.544 Mbps to 45 Mbps (US), 2.048 Mbps to

34 Mbps (European)

Broadband 45 Mbps (US), 34 Mbps (European)

Attenuation Due to resistance and length of transmission medium

Distortion Alteration of information which original proportion is changed

Noise Outside source which corrupts the signal

Distress Needs immediate assistance

Urgency Requires immediate attention

Safety Meteorological information

SECTION 2 : NOISE ANALYSIS AND DB CALCULATIONS

AMPOLOQUIO

Noise Any undesirable energy that falls within the passband of unwanted

signal

Impulse Noise Sudden burst of irregularly shaped pulses

Burst Noise Popcorn Noise; 1/f2

Neper Transmission unit used in Northern European countries used to

express attenuation of current along transmission line using natural

logarithm;

1 Neper = 8.686 Db

RLP Relative level point

TLP Transmission level point; American term for RLP;

0 TLP = 0dBr

dBrn dB above reference noise

dBa dB adjusted

dBrnC dB above reference noise using C-message line weighting

dBrnC = dBa +5 (pure test tone)

dBrnC = dBa +6 (3KHz white noise)

dBmp dB psophometrically weighted

pWp Picowatts psophometrically weighted

Volume Unit Used to measure the power level of program channels and certain

types of speech or music

P (dBm) = VU -1.4

SECTION 3 : AMPLITUDE MODULATION

J. AMPOLOQUIO

Modulation The process of impressing or imparting a low-frequency source

information onto a high-frequency bandpass signal with a carrier

frequency by the introduction of amplitude, frequency or phase

perturbation

Demodulation The reverse process where the received signals are transformed

back to their original form

Amplitude

Modulation

An analog modulation scheme in which the amplitude of relatively

high-frequency carrier signal is varied in accordance with the

instantaneous amplitude of an information signal

AM modulated wave Vam(t) = (Vc + Vmsin mt) sin ct

Coefficient of

Modulation

Describes the amount of amplitude change present in an AM

waveform

Overmodulation Created side frequencies (harmonics) further from the carrier known

as splatter, buckshot, or spurious emissions; overmodulation is illegal

535KHz to 1605KHz Standard AM broadcast band; 107 carrier assignments