FCC Emission Designators

If you have ever obtained a license from the FCC or spent anytime looking at your radios manual you will notice a seven digit code. Like 11K2F3E or 20K0F3E. Its not there for decoration, it actually means something. The first four digits, in the example above, stand for occupied bandwidth in kilohertz. So 20K0 would signify 20 Kilohertz of bandwidth. 11K2 would signify 11.2 kilohertz. The last three digits signify the type of emission. F3E stands for analog voice. Below is a handy guide we put together to help you figure out what these mean:

The letter goes where the decimal point should be placed, and denotes a magnitude:
H        Hz
K        kHz
M        MHz
G        GHz

Some common bandwidths are:

400 Hz     400H
2.4 kHz    2K40
11.2 kHz   11K1
6 MHz      6M00
M = Modulation Type
N   None
A   AM (Amplitude Modulation), double sideband, full carrier
H   AM, single sideband, full carrier
R   AM, single sideband, reduced or controlled carrier
J   AM, single sideband, suppressed carrier
B   AM, independent sidebands
C   AM, vestigial sideband  (commonly analog TV)

F   Angle-modulated, straight FM
G   Angle-modulated, phase modulation (common; sounds like FM)

D   Carrier is amplitude and angle modulated

P   Pulse, no modulation
K   Pulse, amplitude modulation (PAM, PSM)
L   Pulse, width modulation (PWM)
M   Pulse, phase or position modulation (PPM)
Q   Pulse, carrier also angle-modulated during pulse
W   Pulse, two or more modes used

X   All cases not covered above
N = Nature of modulating signal
0   None
1   Digital, on-off or quantized, no modulation
2   Digital, with modulation
3   Single analog channel
7   Two or more digital channels
8   Two or more analog channels
9   Composite, one or more digital channel, one or more analog

X   All cases not covered above
I = Information type
N   None
A   Aural telegraphy, for people (Morse code)
B   Telegraphy for machine copy (RTTY, fast Morse)
C   Analog fax
D   Data, telemetry, telecommand
E   Telephony, voice, sound broadcasting
F   Video, television
W   Combinations of the above

X   All cases not covered above
From: http://fcclicenses.blogspot.com/2011/10/fcc-emission-designators-what-do-codes.html.

See also the FCC's web page on Emission Designators.