Question

in communications. Make a table of FCC Emmision Classification

Answer 1

FCC Emission Classification:

The International Telecommunication Union (ITU) uses an internationally agreed system for classifying radio frequency signals. Each type of radio emission is classified according to its bandwidth, method of modulation, nature of the modulating signal, and type of information transmitted on the carrier signal. It is based on characteristics of the signal, not on the transmitter used.

The ITU designations for the different types of radio emissions follows a standard format. This format helps us to quickly identify the parameters of the particular transmission. Although not all elements of the system may be used every time, it has been developed so that there is no ambiguity whatever part of the system for describing the types of radio emission is used.

A minimum of three symbols are used to describe the basic characteristics of radio waves

An emission designation is of the form

BBBB 123 45

Where BBBB is the bandwidth of the signal,

1 is a letter indicating the type of modulation used of the main carrier (not including any subcarriers which is why FM stereo is F8E and not D8E),

2 is a digit representing the type of modulating signal again of the main carrier,

3 is a letter corresponding to the type of information transmitted,

4 (Optional)is a letter indicating the practical details of the transmitted information (of signal),

5 (optional)is a letter that represents the method of multiplexing.

The 4 and 5 fields are optional. Tables for the different characters 1 to 5 are given below.

This designation system was agreed at the 1979 World Administrative Radio Conference (WARC 79), and gave rise to the Radio Regulations that came into force on 1 January 1982. A similar designation system had been in use under prior Radio Regulations.

Bandwidth designator (BBBB)

The bandwidth (BBBB above) is expressed as four characters: three digits and one letter.

The letter occupies the position normally used for a decimal point, and indicates what unit of frequency is used to express the bandwidth.

The letter H indicates Hertz, K indicates kiloHertz, M indicates megaHertz, and G indicates gigaHertz.

For instance, "500H" means 500 Hz, and "2M50" means 2.5 MHz. The first character must be a digit between 1 and 9; it may not be the digit 0 or a letter.

Character 1 - type of modulation

This character describes the format for the modulation itself. It provides information about the way in which the signal is superimposed onto the carrier.

Character	Description
N	Unmodulated carrier
A	Double-sideband amplitude modulation (e.g. AM broadcast radio)
H	Single-sideband with full carrier (e.g. as used by CHU)
R	Single-sideband with reduced or variable carrier
J	Single-sideband with suppressed carrier (e.g. Shortwave utility and amateur stations)
B	Independent sideband (two sidebands containing different signals)
C	Vestigial sideband (e.g. NTSC)
F	Frequency modulation (e.g. FM broadcast radio)
G	Phase modulation
D	Combination of AM and FM or PM
P	Sequence of pulses without modulation
K	Pulse amplitude modulation
L	Pulse width modulation (e.g. as used by WWVB)
M	Pulse position modulation
Q	Sequence of pulses, phase or frequency modulation within each pulse
V	Combination of pulse modulation methods
W	Combination of any of the above
X	None of the above

Digit 2 - Type of modulating signal

Character	Description
0	No modulating signal
1	One channel containing digital information, no subcarrier
2	One channel containing digital information, using a subcarrier
3	One channel containing analog information
7	More than one channel containing digital information
8	More than one channel containing analog information
9	Combination of analog and digital channels
X	None of the above

Types 4 and 5 were removed from use with the 1982 Radio Regulations. In previous editions, they had indicated facsimile and video, respectively.

Character 3 –Type of transmitted information

Character	Description
N	No transmitted information
A	Aural telegraphy, intended to be decoded by ear, such as Morse code
B	Electronic telegraphy, intended to be decoded by machine (radioteletype and digital modes)
C	Facsimile (still images)
D	Data transmission, telemetry or telecommand (remote control)
E	Telephony (voice or music intended to be listened to by a human)
F	Video (television signals)
W	Combination of any of the above
X	None of the above

4 (Optional) - Type of modulating signal

Character	Description
A	Two-condition code, elements vary in quantity and duration
B	Two-condition code, elements fixed in quantity and duration
C	Two-condition code, elements fixed in quantity and duration, error-correction included
D	Four-condition code, one condition per "signal element"
E	Multi-condition code, one condition per "signal element"
F	Multi-condition code, one character represented by one or more conditions
G	Monophonic broadcast-quality sound
H	Stereophonic or quadraphonic broadcast-quality sound
J	Commercial-quality sound (non-broadcast)
K	Commercial-quality sound—frequency inversion and-or "band-splitting" employed
L	Commercial-quality sound, independent FM signals, such as pilot tones, used to control the demodulated signal
M	Greyscale images or video
N	Full-color images or video
W	Combination of two or more of the above
X	None of the above

5 (optional) Multiplexing

Character	Description
N	None used
C	Code-division (excluding spread spectrum)
F	Frequency-division
T	Time-division
W	Combination of Frequency-division and Time-division
X	None of the above