[Code of Federal Regulations]
[Title 47, Volume 4]
[Revised as of October 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 47CFR73.682]
[Page 221-226]
TITLE 47--TELECOMMUNICATION
COMMISSION (CONTINUED)
PART 73_RADIO BROADCAST SERVICES--Table of Contents
Subpart E_Television Broadcast Stations
Sec. 73.682 TV transmission standards.
(a) Transmission standards. (1) The width of the television
broadcast channel shall be 6 MHz.
(2) The visual carrier frequency shall be nominally 1.25 MHz above
the lower boundary of the channel.
(3) The aural center frequency shall be 4.5 MHz higher than the
visual carrier frequency.
(4) The visual transmission amplitude characteristic shall be in
accordance with the chart designated as Figure 5 of Sec. 73.699:
Provided, however, That for stations operating on Channel 15 through 69
and employing a transmitter with maximum peak visual power output of 1
kW or less the visual transmission amplitude characteristic may be in
accordance with the chart designated as Figure 5a of Sec. 73.699.
(5) The chrominance subcarrier frequency is 63/88 times precisely 5
MHz (3.57954545 . . . MHz). The tolerance is +- 10 Hz and the rate of
frequency drift must not exceed 0.1 Hz per second (cycles per second
squared).
(6) For monochrome and color transmissions the number of scanning
lines per frame shall be 525, interlaced two to one in successive
fields. The horizontal scanning frequency shall be 2/455 times the
chrominance subcarrier frequency; this corresponds nominally to 15,750
Hz with an actual value of 15,734.264 +-0.044 Hz). The vertical scanning
frequency is 2/525 times the horizontal scanning frequency; this
corresponds nominally to 60 Hz (the actual value is 59.94 Hz). For
monochrome transmissions only, the nominal values of line and field
frequencies may be used.
(7) The aspect ratio of the transmitted television picture shall be
4 units horizontally to 3 units vertically.
(8) During active scanning intervals, the scene shall be scanned
from left to right horizontally and from top to bottom vertically, at
uniform velocities.
(9) A carrier shall be modulated within a single television channel
for both picture and synchronizing signals. The two signals comprise
different modulation ranges in amplitude in accordance with the
following:
(i) Monochrome transmissions shall comply with synchronizing
waveform specifications in Figure 7 of Sec. 73.699.
(ii) Color transmissions shall comply with the synchronizing
waveform specifications in Figure 6 of Sec. 73.699.
(iii) All stations operating on Channels 2 through 14 and those
stations operating on Channels 15 through 69 licensed for a peak visual
transmitter output power greater than one kW shall comply with the
picture transmission amplitude characteristics shown in Figure 5 of
Sec. 73.699.
(iv) Stations operating on Channels 15 through 69 licensed for a
peak visual transmitter output power of one kW or less shall comply with
the picture transmission amplitude characteristic shown in Figure 5 or
5a of Sec. 73.699.
(10) A decrease in initial light intensity shall cause an increase
in radiated power (negative transmission).
(11) The reference black level shall be represented by a definite
carrier level, independent of light and shade in the picture.
(12) The blanking level shall be transmitted at 75+-2.5 percent of
the peak carrier level.
(13) The reference white level of the luminance signal shall be
12.5+-2.5 percent of the peak carrier level.
(14) It shall be standard to employ horizontal polarization.
However, circular or elliptical polarization may be employed if desired,
in which case clockwise (right hand) rotation, as defined in the IEEE
Standard Definition
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42A65-3E2, and transmission of the horizontal and vertical components in
time and space quadrature shall be used. For either omnidirectional or
directional antennas the licensed effective radiated power of the
vertically polarized component may not exceed the licensed effective
radiated power of the horizontally polarized component. For directional
antennas, the maximum effective radiated power of the vertically
polarized component shall not exceed the maximum effective radiated
power of the horizontally polarized component in any specified
horizontal or vertical direction.
(15) The effective radiated power of the aural transmitter must not
exceed 22% of the peak radiated power of the visual transmitter.
(16) The peak-to-peak variation of transmitter output within one
frame of video signal due to all causes, including hum, noise, and low-
frequency response, measured at both scanning synchronizing peak and
blanking level, shall not exceed 5 percent of the average scanning
synchronizing peak signal amplitude. This provision is subject to change
but is considered the best practice under the present state of the art.
It will not be enforced pending a further determination thereof.
(17) The reference black level shall be separated from the blanking
level by the setup interval, which shall be 7.5+-2.5 percent of the
video range from blanking level to the reference white level.
(18) For monochrome transmission, the transmitter output shall vary
in substantially inverse logarithmic relation to the brightness of the
subject. No tolerances are set at this time. This provision is subject
to change but is considered the best practice under the present state of
the art. It will not be enforced pending a further determination
thereof.
(19) The color picture signal shall correspond to a luminance
component transmitted as amplitude modulation of the picture carrier and
a simultaneous pair of chrominance components transmitted as the
amplitude modulation sidebands of a pair of suppressed subcarriers in
quadrature.
(20) Equation of complete color signal.
(i) The color picture signal has the following composition:
EM=EY'+[EQ' sin ([omega]t+33[deg])+EI' cos ([omega]t+33[deg])]
Where:
EQ'=0.41(EB'-EY')+0.48(ER'-EY').
EI'=-0.27(EB'-EY')+0.74(ER'-EY').
EY'=0.30ER'+0.59EG'+0.-1EB'.
For color-difference frequencies below 500 kHz (see (iii) below), the
signal can be represented by:
EM=EY'+[(1/1.14)[(1/1.78)(EB'-EY') sin [omega]t+(ER'-EY') cos [omega]t]]
(ii) The symbols in paragraph (a)(20)(i) of this section have the
following significance:
EM is the total video voltage, corresponding to the scanning of a
particular picture element, applied to the modulator of the picture
transmitter.
EY' is the gamma-corrected voltage of the monochrome (black-and-white)
portion of the color picture signal, corresponding to the given picture
element.
Note: Forming of the high frequency portion of the monochrome signal
in a different manner is permissible and may in fact be desirable in
order to improve the sharpness on saturated colors.
EQ' and EI' are the amplitudes of two orthogonal components of the
chrominance signal corresponding respectively to narrow-band and wide-
band axes.
ER', EG', and EB' are the gamma-corrected voltages corresponding to
red, green, and blue signals during the scanning of the given picture
element.
[omega] is the angular frequency and is 2 times the frequency of the
chrominance subcarrier.
The portion of each expression between brackets in (i) represents
the chrominance subcarrier signal which carries the chrominance
information.
The phase reference in the EM equation in (i) is the phase of the
burst+180[deg], as shown in Figure 8 of Sec. 73.699. The burst
corresponds to amplitude modulation of a continuous sine wave.
(iii) The equivalent bandwidth assigned prior to modulation to the
color difference signals EQ' and EI' are as follows:
Q-channel bandwidth:
At 400 kHz less than 2 dB down.
At 500 kHz less than 6 dB down.
At 600 kHz at least 6 dB down.
I-channel bandwidth:
At 1.3 MHz less than 2 dB down.
At 3.6 MHz at least 20 dB down.
[[Page 223]]
(iv) The gamma corrected voltages ER', EG', and EB' are suitable for
a color picture tube having primary colors with the following
chromaticities in the CIE system of specification:
x y
Red (R)................................................. 0.67 0.33
Green (G)............................................... 0.21 0.71
Blue (B)................................................ 0.14 0.08
and having a transfer gradient (gamma exponent) of 2.2 associated with
each primary color. The voltages ER', EG', and EB' may be respectively
of the form ER 1/[gamma], EG 1/[gamma], and EB 1/[gamma] although other
forms may be used with advances in the state of the art.
Note: At the present state of the art it is considered inadvisable
to set a tolerance on the value of gamma and correspondingly this
portion of the specification will not be enforced.
(v) The radiated chrominance subcarrier shall vanish on the
reference white of the scene.
Note: The numerical values of the signal specification assume that
this condition will be reproduced as CIE Illuminant C (x=0.310,
y=0.316).
(vi) EY', EQ', EI', and the components of these signals shall match
each other in time to 0.05 [mu] secs.
(vii) The angles of the subcarrier measured with respect to the
burst phase, when reproducing saturated primaries and their complements
at 75 percent of full amplitude, shall be within +-10[deg] and their
amplitudes shall be within +-20 percent of the values specified above.
The ratios of the measured amplitudes of the subcarrier to the luminance
signal for the same saturated primaries and their complements shall fall
between the limits of 0.8 and 1.2 of the values specified for their
ratios. Closer tolerances may prove to be practicable and desirable with
advance in the art.
(21) The interval beginning with line 17 and continuing through line
20 of the vertical blanking interval of each field may be used for the
transmission of test signals, cue and control signals, and
identification signals, subject to the conditions and restrictions set
forth below. Test signals may include signals designed to check the
performance of the overall transmission system or its individual
components. Cue and control signals shall be related to the operation of
the TV broadcast station. Identification signals may be transmitted to
identify the broadcast material or its source, and the date and time of
its origination. Figures 6 and 7 of Sec. 73.699 identify the numbered
lines referred to in this paragraph.
(i) Modulation of the television transmitter by such signals shall
be confined to the area between the reference white level and the
blanking level, except where test signals include chrominance subcarrier
frequencies, in which case positive excursions of chrominance components
may exceed reference white, and negative excursions may extend into the
synchronizing area. In no case may the modulation excursions produced by
test signals extend beyond peak-of-sync, or to zero carrier level.
(ii) The use of such signals shall not result in significant
degradation of the program transmission of the television broadcast
station, nor produce emission outside of the frequency band occupied for
normal program transmissions.
(iii) Such signals may not be transmitted during that portion of
each line devoted to horizontal blanking.
(iv) Regardless of other provisions of this paragraph, after June
30, 1994, Line 19, in each field, may be used only for the transmission
of the ghost-canceling reference signal described in OET Bulletin No.
68, which is available from the FCC Warehouse, 9300 East Hampton Drive,
Capitol Heights, MD 20743. Notwithstanding the modulation limits
contained in paragraph (a)(23)(i) of this section, the vertical interval
reference signal formerly permitted on Line 19 and described in Figure
16 of Sec. 73.699, may be transmitted on any of lines 10 through 16
without specific Commission authorization, subject to the conditions
contained in paragraphs (a)(21)(ii) and (a)(22)(ii) of this section.
(22)(i) Line 21, in each field, may be used for the transmission of
a program-related data signal which, when decoded, provides a visual
depiction of information simultaneously being presented on the aural
channel (captions).
[[Page 224]]
Line 21, field 2 may be used for transmission of a program-related data
signal which, when decoded, identifies a rating level associated with
the current program. Such data signals shall conform to the format
described in figure 17 of Sec. 73.699 of this chapter, and may be
transmitted during all periods of regular operation. On a space
available basis, line 21 field 2 may also be used for text-mode data and
extended data service information.
Note: The signals on Fields 1 and 2 shall be distinct data streams,
for example, to supply captions in different languages or at different
reading levels.
(ii) At times when Line 21 is not being used to transmit a program
related data signal, data signals which are not program related may be
transmitted, Provided: the same data format is used and the information
to be displayed is of a broadcast nature.
(iii) The use of Line 21 for transmission of other data signals
conforming to other formats may be used subject to prior authorization
by the Commission.
(iv) The data signal shall cause no significant degradation to any
portion of the visual signal nor produce emissions outside the
authorized television channel.
(v) Transmission of visual emergency messages pursuant to Sec.
73.1250 shall take precedence and shall be cause for interrupting
transmission of data signals permitted under this paragraph.
(23) Specific scanning lines in the vertical blanking interval may
be used for the purpose of transmitting telecommunications signals in
accordance with Sec. 73.646, subject to certain conditions:
(i) Telecommunications may be transmitted on Lines 10-18 and 20, all
of Field 2 and Field 1. Modulation level shall not exceed 70 IRE on
lines 10, 11, and 12; and, 80 IRE on lines 13-18 and 20.
(ii) No observable degradation may be caused to any portion of the
visual or aural signals.
(iii) Telecommunications signals must not produce emissions outside
the authorized television channel bandwidth. Digital data pulses must be
shaped to limit spectral energy to the nominal video baseband.
(iv) Transmission of emergency visual messages pursuant to Sec.
73.1250 must take precedence over, and shall be cause for interrupting,
a service such as teletext that provides a visual depiction of
information simultaneously transmitted on the aural channel.
(v) A reference pulse for a decoder associated adaptive equalizer
filter designed to improve the decoding of telecommunications signals
may be inserted on any portion of the vertical blanking interval
authorized for data service, in accordance with the signal levels set
forth in paragraph (a)(23)(i) of this section.
(vi) All lines authorized for telecommunications transmissions may
be used for other purposes upon prior approval by the Commission.
(24) Licensees and permittees of TV broadcast and low power TV
stations may insert non-video data into the active video portion of
their TV transmission, subject to certain conditions:
(i) The active video portion of the visual signal begins with line
22 and continues through the end of each field, except it does not
include that portion of each line devoted to horizontal blanking.
Figures 6 and 7 of Sec. 73.699 identify the numbered line referred to
in this paragraph;
(ii) Inserted non-video data may be used for the purpose of
transmitting a telecommunications service in accordance with Sec.
73.646. In addition to a telecommunications service, non-video data can
be used to enhance the station's broadcast program service or for
purposes related to station operations. Signals relating to the
operation of TV stations include, but are not limited to program or
source identification, relay of broadcast materials to other stations,
remote cueing and order messages, and control and telemetry signals for
the transmitting system; and
(iii) A station may only use systems for inserting non-video
information that have been approved in advance by the Commission. The
criteria for advance approval of systems are as follows:
(A) The use of such signals shall not result in significant
degradation to any portion of the visual, aural, or program-related data
signals of the television broadcast station;
[[Page 225]]
(B) No increase in width of the television broadcast channel (6 MHz)
is permitted. Emissions outside the authorized television channel must
not exceed the limitations given in Sec. 73.687(e). Interference to
reception of television service either of co-channel or adjacent channel
stations must not increase over that resulting from the transmission of
programming without inserted data; and
(C) Where required, system receiving or decoding devices must meet
the TV interface device provisions of Part 15, Subpart H of this
chapter.
(iv) No protection from interference of any kind will be afforded to
reception of inserted non-video data.
(v) Upon request by an authorized representative of the Commission,
the licensee of a TV station transmitting encoded programming must make
available a receiving decoder to the Commission to carry out its
regulatory responsibilities.
(b) Subscription TV technical systems. The FCC may specify, as part
of the advance approval of the technical system for transmitting encoded
subscription programming, deviations from the power determination
procedures, operating power levels, aural or video baseband signals,
modulation levels or other characteristics of the transmitted signal as
otherwise specified in this Subpart. Any decision to approve such
operating deviations shall be solely at the discretion of the FCC.
(c) TV multiplex subcarrier/stereophonic aural transmission
standards.
(1) The modulating signal for the main channel shall consist of the
sum of the stereophonic (biphonic, quadraphonic, etc.) input signals.
(2) The instantaneous frequency of the baseband stereophonic
subcarrier must at all times be within the range 15 kHz to 120 kHz.
Either amplitude or frequency modulation of the stereophonic subcarrier
may be used.
(3) One or more pilot subcarriers between 16 kHz and 120 kHz may be
used to switch a TV receiver between the stereophonic and monophonic
reception modes or to activate a stereophonic audio indicator light, and
one or more subcarriers between 15 kHz and 120 kHz may be used for any
other authorized purpose; except that stations employing the BTSC system
of stereophonic sound transmission and audio processing may transmit a
pilot subcarrier at 15,734 Hz, +- 2 Hz. Other methods of multiplex
subcarrier or stereophonic aural transmission systems must limit energy
at 15,734 Hz, +- 20 Hz, to no more than +- 0.125 kHz aural carrier
deviation.
(4) Aural baseband information above 120 kHz must be attenuated 40
dB referenced to 25 kHz main channel deviation of the aural carrier.
(5) For required transmitter performance, all of the requirements of
Sec. 73.687(b) shall apply to the main channel, with the transmitter in
the multiplex subcarrier or stereophonic aural mode.
(6) For electrical performance standards of the transmitter, the
requirements of Sec. 73.687(b) apply to the main channel.
(7) Multiplex subcarrier or stereophonic aural transmission systems
must be capable of producing and must not exceed +- 25 kHz main channel
deviation of the aural carrier.
(8) The arithmetic sum of non-multiphonic baseband signals between
15 kHz and 120 kHz must not exceed +-50 kHz deviation of the aural
carrier.
(9) Total modulation of the aural carrier must not exceed +- 75 kHz.
(d) Digital broadcast television transmission standard. Transmission
of digital broadcast television (DTV) signals shall comply with the
standards for such transmissions set forth in Advanced Television
Systems Committee (ATSC) Doc. A/52, ATSC Standard Digital Audio
Compression (AC-3), December 20, 1995 and ATSC Doc. A/53B, Revision B,
with Amendment 1, ATSC Digital Television Standard, August 7, 2001,
except for Section 5.1.2 (``Compression format constraints'') of Annex A
(``Video Systems Characteristics'') and the phrase ``see Table 3'' in
Section 5.1.1 Table 2 and Section 5.1.2 Table 4. This incorporation by
reference was approved by the Director of the Federal Register in
accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be
inspected at the Federal Communications Commission, 445 12th St., SW,
Washington, DC 20554 or at the Office of the Federal Register, 800 N.
Capitol St., NW, Suite 700, Washington, DC.
[[Page 226]]
Copies of ATSC A/52, A/53, A/54, and A/65 can be obtained from the
Commission's contract copier or from the Advanced Television Systems
Committee, 1750 K St., NW, Washington, DC 20006. They are also available
in their entirety on the Internet at http://www.atsc.org. Although not
incorporated by reference, licensees may also consult ATSC Doc. A/54,
Guide to Use of the ATSC Digital Television Standard, October 4, 1995,
and ATSC Doc. A/65A, Program System and Information Protocol (PSIP) for
Terrestrial Broadcast and Cable, December 23, 1997 for guidance.
(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154,
155, 303))
[28 FR 13660, Dec. 14, 1963]
Editorial Note: For Federal Register citations affecting Sec.
73.682, see the List of CFR Sections Affected, which appears in the
Finding Aids section of the printed volume and on GPO Access.