Sec.  2.202   Bandwidths.

   (a) Occupied bandwidth. The frequency bandwidth such that, below its lower
   and above its upper frequency limits, the mean powers radiated are each
   equal to 0.5 percent of the total mean power radiated by a given emission.
   In some cases, for example multichannel frequency-division systems, the
   percentage of 0.5 percent may lead to certain difficulties in the practical
   application of the definitions of occupied and necessary bandwidth; in such
   cases a different percentage may prove useful.

   (b) Necessary bandwidth. For a given class of emission, the minimum value of
   the occupied bandwidth sufficient to ensure the transmission of information
   at the rate and with the quality required for the system employed, under
   specified conditions. Emissions useful for the good functioning of the
   receiving equipment as, for example, the emission corresponding to the
   carrier of reduced carrier systems, shall be included in the necessary
   bandwidth.

   (1) The necessary bandwidth shall be expressed by three numerals and one
   letter. The letter occupies the position of the decimal point and represents
   the unit of bandwidth. The first character shall be neither zero nor K, M or
   G.

   (2) Necessary bandwidths:

   between 0.001 and 999 Hz shall be expressed in Hz (letter H);

   between 1.00 and 999 kHz shall be expressed in kHz (letter K);

   between 1.00 and 999 MHz shall be expressed in MHz (letter M);

   between 1.00 and 999 GHz shall be expressed in GHz (letter G).

   (3) Examples:

   0.002 Hz—H002
   0.1 Hz—H100
   25.3 Hz—25H3
   400 Hz—400H
   2.4 kHz—2K40
   6 kHz—6K00
   12.5 kHz—12K5
   180.4 kHz—180K
   180.5 kHz—181K
   180.7 kHz—181K
   1.25 MHz—1M25
   2 MHz—2M00
   10 MHz—10M0
   202 MHz—202M
   5.65 GHz—5G65

   (c) The necessary bandwidth may be determined by one of the following
   methods:

   (1) Use of the formulas included in the table, in paragraph (g) of this
   section, which also gives examples of necessary bandwidths and designation
   of corresponding emissions;

   (2) For frequency modulated radio systems which have a substantially linear
   relationship between the value of input voltage to the modulator and the
   resulting frequency deviation of the carrier and which carry either single
   sideband suppressed carrier frequency division multiplex speech channels or
   television, computation in accordance with provisions of paragraph (f) of
   this section and formulas and methods indicated in the table, in paragraph
   (g) of this section;

   (3) Computation in accordance with Recommendations of the International
   Radio Consultative Committee (C.C.I.R.);

   (4) Measurement in cases not covered by paragraph (c) (1), (2), or (3) of
   this section.

   (d) The value so determined should be used when the full designation of an
   emission is required. However, the necessary bandwidth so determined is not
   the only characteristic of an emission to be considered in evaluating the
   interference that may be caused by that emission.

   (e) In the formulation of the table in paragraph (g) of this section, the
   following terms are employed:

   B[n] = Necessary bandwidth in hertz

   B = Modulation rate in bauds

   N = Maximum possible number of black plus white elements to be transmitted
   per second, in facsimile

   M = Maximum modulation frequency in hertz

   C = Sub-carrier frequency in hertz

   D = Peak frequency deviation, i.e., half the difference between the maximum
   and minimum values of the instantaneous frequency. The instantaneous
   frequency in hertz is the time rate of change in phase in radians divided by
   2

   t = Pulse duration in seconds at half-amplitude

   t[r] = Pulse rise time in seconds between 10% and 90% of maximum amplitude

   K = An overall numerical factor which varies according to the emission and
   which depends upon the allowable signal distortion.

   N[c] = Number of baseband telephone channels in radio systems employing
   multichannel multiplexing

   P = Continuity pilot sub-carrier frequency (Hz) (continuous signal utilized
   to verify performance of frequency-division multiplex systems).

   (f) Determination of values of D and B[n] for systems specified in paragraph
   (c)(2) of this section:

   (1) Determination of D in systems for multichannel telephony:

   (i) The rms value of the per-channel deviation for the system shall be
   specified. (In the case of systems employing preemphasis or phase
   modulation, this value of per-channel deviation shall be specified at the
   characteristic baseband frequency.)

   (ii) The value of D is then calculated by multiplying the rms value of the
   per-channel deviation by the appropriate factors, as follows:


-------------------------------------------------------------------------------
---------------------------------
       Number of message circuits                Multiplying factors
   Limits of X (Pavg (dBmO))
-------------------------------------------------------------------------------
---------------------------------
More than 3, but less than 12..........  4.47 x [a factor specified by the
                                          equipment manufacturer or station
                                          licensee, subject to Commission
                                          approval].
                                             3.76 antilog (X+2 log10 Nc)
At least 12, but less than 60..........             _____________            X:
 -2 to +2.6.
                                                         20
                                             3.76 antilog (X+4 log10 Nc)
At least 60, but less than 240.........             _____________            X:
 -5.6 to -1.0.
                                                         20
                                            3.76 antilog (X+10 log10 Nc)
240 or more............................             _____________            X:
 -19.6 to -15.0.
                                                         20
-------------------------------------------------------------------------------
---------------------------------
Where X represents the average power in a message circuit in dBmO; Nc is the nu
mber of circuits in the
  multiplexed message load; 3.76 corresponds to a peak load factor of 11.5 dB.

   (2) The necessary bandwidth (B[n]) normally is considered to be numerically
   equal to:

   (i) 2M+2DK, for systems having no continuity pilot subcarrier or having a
   continuity pilot subcarrier whose frequency is not the highest modulating
   the main carrier;

   (ii) 2P+2DK, for systems having a continuity pilot subcarrier whose
   frequency exceeds that of any other signal modulating the main carrier,
   unless the conditions set forth in paragraph (f)(3) of this section are met.

   (3) As an exception to paragraph (f)(2)(ii) of this section, the necessary
   bandwidth (B[n]) for such systems is numerically equal to 2P or 2M+2DK,
   whichever is greater, provided the following conditions are met:

   (i) The modulation index of the main carrier due to the continuity pilot
   subcarrier does not exceed 0.25, and

   (ii) In a radio system of multichannel telephony, the rms frequency
   deviation of the main carrier due to the continuity pilot subcarrier does
   not exceed 70 percent of the rms value of the per-channel deviation, or, in
   a radio system for television, the rms deviation of the main carrier due to
   the pilot does not exceed 3.55 percent of the peak deviation of the main
   carrier.

   (g) Table of necessary bandwidths:


-------------------------------------------------------------------------------
-------------------------------------------------------------------------
                                                                          Neces
sary bandwidth
       Description of emission        -----------------------------------------
------------------------------------------------- Designation of emission
                                                       Formula
               Sample calculation
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
                                                                 I. NO MODULATI
NG SIGNAL
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
Continuous wave emission.............  ......................................
................................................  N0N (zero)
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
                                                                II. AMPLITUDE M
ODULATION
 1. Signal With Quantized or Digital
             Information
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
Continuous wave telegraphy...........  Bn=BK, K=5 for fading circuits, K=3
25 words per minute; B=20, K=5, Bandwidth: 100    100HA1A
                                        for non-fading circuits
 Hz
Telegraphy by on-off keying of a tone  Bn=BK+2M, K=5 for fading circuits, K=3
25 words per minute; B=20, M=1000, K=5,           2K10A2A
 modulated carrier.                     for non-fading circuits
 Bandwidth: 2100 Hz=2.1 kHz
Selective calling signal, single-      Bn=M
Maximum code frequency is: 2110 Hz, M=2110,       2K11H2B
 sideband full carrier.
 Bandwidth: 2110 Hz=2.11 kHz
Direct-printing telegraphy using a     Bn=2M+2DK, M=B÷2                   B=50,
 D=35 Hz (70 Hz shift), K=1.2, Bandwidth:    134HJ2B
 frequency shifted modulating sub-
 134 Hz
 carrier single-sideband suppressed
 carrier.
Telegraphy, single sideband reduced    Bn=central frequency+M+DK, M=B÷2   15 ch
annels; highest central frequency is: 2805   2K89R7B
 carrier.
 Hz, B=100, D=42.5 Hz (85 Hz shift), K=0.7

 Bandwidth: 2.885 Hz=2.885 kHz
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
                                                            2. Telephony (Comme
rcial Quality)
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
Telephony double-sideband............  Bn=2M
M=3000, Bandwidth=6000 Hz=6 kHz                   6K00A3E
Telephony, single-sideband, full       Bn=2M
M=3000, Bandwidth: 3000 Hz=3 kHz                  3K00H3E
 carrier.
Telephony, single-sideband suppressed  Bn=M-lowest modulation frequency
M=3000, lowest modulation frequency is 3000 Hz,   2K70J3E
 carrier.
 2700 Hz Bandwidth: 2700Hz=2.7 kHz
Telephony with separate frequency      Bn=M
Maximum control frequency is 2990 Hz, M=2990,     2K99R3E
 modulated signal to control the
 Bandwidth: 2990 Hz=2.99 kHz
 level of demodulated speech signal,
 single-sideband, reduced carrier.
Telephony with privacy, single-        Bn=Nc M-lowest modulation frequency in
Nc=2, M=3000 lowest modulation frequency is 250   5K75J8E
 sideband, suppressed carrier (two or   the lowest channel
 Hz, Bandwidth: 5750 Hz=5.75 kHz
 more channels).
Telephony, independent sideband (two   Bn=sum of M for each sideband
2 channels, M=3000, Bandwidth: 6000 Hz=6 kHz      6K00B8E
 or more channels).
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
                                                                  3. Sound Broa
dcasting
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
Sound broadcasting, double-sideband..  Bn=2M, M may vary between 4000 and
Speech and music, M=4000, Bandwidth: 8000 Hz= 8   8K00A3E
                                        10000 depending on the quality
 kHz
                                        desired
Sound broadcasting, single-sideband    Bn=M, M may vary between 4000 and
Speech and music, M=4000, Bandwidth: 4000 Hz= 4   4K00R3E
 reduced carrier (single channel).      10000 depending on the quality
 kHz
                                        desired
Sound broadcasting, single-sideband,   Bn=M-lowest modulation frequency
Speech and music, M=4500, lowest modulation       4K45J3E
 suppressed carrier.
 frequency=50 Hz, Bandwidth: 4450 Hz=4.45 kHz
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
                                                                      4. Televi
sion
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
Television, vision and sound.........  Refer to CCIR documents for the
Number of lines=525; Nominal video bandwidth:     5M75C3F
                                        bandwidths of the commonly used
 4.2 MHz, Sound carrier relative to video
                                        television systems
 carrier=4.5 MHz
                                       ......................................
Total vision bandwidth: 5.75 MHz; FM aural        250KF3E

 bandwidth including guardbands: 250,000 Hz
                                       ......................................
Total bandwidth: 6 MHz                            6M25C3F
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
                                                                      5. Facsim
ile
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
Analogue facsimile by sub-carrier      Bn=C-N÷2+DK, K=1.1 (typically)     N=110
0, corresponding to an index of cooperation  2K89R3C
 frequency modulation of a single-
 of 352 and a cycler rotation speed of 60 rpm.
 sideband emission with reduced
 Index of cooperation is the product of the drum
 carrier.
 diameter and number of lines per unit length

 C=1900, D=400 Hz, Bandwidth=2.890 Hz=2.89 kHz
Analogue facsimile; frequency          Bn=2M+2DK, M=N/2, K=1.1 (typically)
N=1100, D=400 Hz, Bandwidth: 1980 Hz=1.98 kHz     1K98J3C
 modulation of an audio frequency sub-
 carrier which modulates the main
 carrier, single-sideband suppressed
 carrier.
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
                                                                 6. Composite E
missions
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
Double-sideband, television relay....  Bn=2C+2M+2D
Video limited to 5 MHz, audio on 6.5 MHz          13M2A8W

 frequency modulated subcarrier deviation=50

 kHz: C=6.5x106 D=50x103 Hz, M=15,000,

 Bandwidth: 13.13x106 Hz=13.13 MHz
Double-sideband radio relay system...  Bn=2M
10 voice channels occupying baseband between 1    328KA8E

 kHz and 164 kHz; M=164,000 bandwith=328,000

 Hz=328 kHz
Double-sideband emission of VOR with   Bn=2Cmax+2M+2DK, K=1 (typically)
The main carrier is modulated by: _a 30 Hz sub-   20K9A9W
 voice (VOR=VHF omnidirectional radio
 carrier_a carrier resulting from a 9960 Hz tone
 range).
 frequency modulated by a 30 Hz tone_a telephone

 channel_a 1020 Hz keyed tone for continual

 Morse identification. Cmax=9960, M=30, D=480

 Hz, Bandwidth: 20,940 Hz=20.94 kHz
Independent sidebands; several         Bn=sum of M for each sideband
Normally composite systems are operated in        12K0B9W
 telegraph channels together with
 accordance with standardized channel
 several telephone channels.
 arrangements, (e.g. CCIR Rec. 348-2) 3

 telephone channels and 15 telegraphy channels

 require the bandwidth 12,000 Hz=12 kHz
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
                                                               III-A. FREQUENCY
 MODULATION
 1. Signal With Quantized or Digital
             Information
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
Telegraphy without error-correction    Bn=2M+2DK, M=B÷2, K=1.2            B=100
, D=85 Hz (170 Hz shift), Bandwidth: 304 Hz  304HF1B
 (single channel).                      (typically)
Four-frequency duplex telegraphy.....  Bn2M+2DK, B=Modulation rate in bands
Spacing between adjacent frequencies=400 Hz;      1K42F7B
                                        of the faster channel. If the
 Synchronized channels; B=100, M=50, D=600 Hz,
                                        channels are synchronized:
 Bandwidth: 1420 Hz=1.42 kHz
                                        M=B÷2, otherwise M=2B, K=1.1
                                        (typically)
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
                                                            2. Telephony (Comme
rcial Quality)
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
Commercial telephony.................  Bn=2M+2DK, K=1 (typically, but under
For an average case of commercial telephony,      16K0F3E
                                        conditions a higher value may be
 M=3,000, Bandwidth: 16,000 Hz=16 kHz
                                        necessary
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
                                                                  3. Sound Broa
dcasting
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
Sound broadcasting...................  Bn=2M+2DK, K=1 (typically)
Monaural, D=75,000 Hz, M=15,000, Bandwidth:       180KF3E

 18,000 Hz=180 kHz
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
                                                                      4. Facsim
ile
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
Facsimile by direct frequency          Bn=2M+2DK, M=N÷2, K=1.1            N=110
0 elements/sec; D=400 Hz, Bandwidth: 1980    1K98F1C
 modulation of the carrier; black and   (typically)
 Hz=1.98 kHZ
 white.
Analogue facsimile...................  Bn=2M+2DK, M=N÷2, K=1.1            N=110
0 elements/sec; D=400 Hz, Bandwidth: 1980    1K98F3C
                                        (typically)
 Hz=1.98 kHz
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
                                                        5. Composite Emissions
(See Table III-B)
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
Radio-relay system, frequency          Bn=2P+2DK, K=1
Microwave radio relay system specifications: 60   2M45F8E
 division multiplex.
 telephone channels occupying baseband between

 60 and 300 kHz; rms per-channel deviation 200

 kHz; pilot at 331 kHz produces 200 kHz rms

 deviation of main carrier. Computation of Bn :

 D=(200x1033x3.76x1.19), Hz=0.895x106,

 P=0.331x106 Hz; Bandwidth: 2.452x106 Hz
Radio-relay system frequency division  Bn=2M+2DK, K=1
Microwave radio relay relay systems               16M6F8E
 multiple.
 specifications: 1200 telephone channels

 occupying baseband between 60 and 5564 kHz; rms

 per channel deviation 200 kHz; continunity

 pilot at 6199 kHz produces 140 kHz rms

 deviation of main carrier. Computation of Bn :

 D=(200x103x 3.76x3.63)=2.73x106; M=5.64x106 Hz;

 P=6.2x106 Hz; (2M+2DK<2P; Bandwidth

 16.59x106 Hz
Radio-relay system, frequency          Bn=2P
Microwave radio relay system specifications:      17M0F8E
 division multiplex.
 Multiplex 600 telephone channels occupying

 baseband between 60 and 2540 kHz; continuity

 pilot at 8500 kHz produces 140 kHz rms

 deviation of main carrier. Computation of Bn :

 D=(200x103x3.76x2.565)=1.93x106 Hz; M=2.54x106

 Hz; 2DK)[le]2P Bandwidth: 17x106 Hz
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
Unmodulated pulse emission...........  Bn=2K÷t, K depends upon the ratio  Prima
ry Radar Range resolution: 150 m, K=1.5      3M00P0N
                                        of pulse rise time. Its value usually
 (triangular pulse where t[sime]tr, only
                                        falls between 1 and 10 and in many
 components down to 27 dB from the strongest are
                                        cases it does not need to exceed 6
 considered) Then t=2xrange

 resolution÷velocity of

 light=2x150÷3x108=1x10-6 seconds,

 Bandwidth: 3x106 Hz=3 MHz
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
                                                                 6. Composite E
missions
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
Radio-relay system...................  Bn=2K÷t, K=1.6                     Pulse
 position modulated by 36 voice channel      8M00M7E

 baseband; pulse width at half amplitude=0.4 us,

 Bandwidth: 8x106 Hz=8 MHz (Bandwidth

 independent of the number of voice channels)
Radio-relay system...................  Bn = 2K/t
Pulse position modulated by 36 voice channel      8M00M7E
                                       K=1.6
 baseband: pulse width at half amplitude 0.4 mS;

 Bn = 8x10 \6\ Hz = 8 MHz (Bandwidth independent

 of the number of voice channels)
Composite transmission digital         Bn = 2RK/log2S
Digital modulation used to send 5 megabits per    5M00K7
 modulation using DSB-AM (Microwave
 second by use of amplitude modulation of the
 radio relay system).
 main carrier with 4 signaling states

R = 5x10 \6\ bits per second; K = 1; S = 4; Bn =

 5 MHz
Binary Frequency Shift Keying........  (0.03 < 2D/R < 1.0);              Digita
l modulation used to send 1 megabit per     2M80F1D
                                       Bn = 3.86D + 0.27R
 second by frequency shift keying with 2
                                       (1.0 < 2D/R <2)                    signa
ling states and 0.75 MHz peak deviation of
                                       Bn = 2.4D + 1.0R
 the carrier

R = 1x10 6 bps; D = 0.75x10 6 Hz; Bn = 2.8 MHz
Multilevel Frequency Shift Keying....  Bn = (R/log2S) + 2DK
Digital modulation to send 10 megabits per        9M00F7D

 second by use of frequency shift keying with

 four signaling states and 2 MHz peak deviation

 of the main carrier

R = 10x10 \6\ bps; D = 2 MHz; K = 1; S = 4; Bn =

 9 MHz
Phase Shift Keying...................  Bn = 2RK/log2S
Digital modulation used to send 10 megabits per   10M0G7D

 second by use of phase shift keying with 4

 signaling states

R = 10x10 \6\ bps; K = 1; S = 4; Bn = 10 MHz
Quadrature Amplitude Modulation (QAM)  Bn = 2R/log2S
64 QAM used to send 135 Mbps has the same         45M0W

 necessary bandwidth as 64-PSK used to send 135

 Mbps;

R = 135x10 \6\ bps; S = 64; Bn = 45 MHz
Minimum Shift Keying.................  2-ary:
Digital modulation used to send 2 megabits per    2M36G1D
                                       Bn = R(1.18)
 second using 2-ary minimum shift keying
                                       4-ary:
R = 2.36x10 \6\ bps; Bn = 2.36 MHz
                                       Bn = R(2.34)
-------------------------------------------------------------------------------
-------------------------------------------------------------------------

   [ 28 FR 12465 , Nov. 22, 1963, as amended at  37 FR 8883 , May 2, 1972;  37 FR 9996 , May 18, 1972;  48 FR 16492 , Apr. 18, 1983;  49 FR 48698 , Dec. 14, 1984;
    68 FR 68543 , Dec. 9, 2003]

Subpart D—Call Signs and Other Forms of Identifying Radio Transmissions

   Authority:   Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082; 47
   U.S.C. 154, 155, 303.