Goto Section: 76.601 | 76.606 | Table of Contents
FCC 76.605
Revised as of
Goto Year:1996 |
1998
Sec. 76.605 Technical standards.
(a) As of December 30, 1992, unless otherwise noted, the following
requirements apply to the performance of a cable television system as
measured at any subscriber terminal with a matched impedance at the
termination point or at the output of the modulating or processing
equipment (generally the headend) of the cable television system or
otherwise as noted. The requirements are applicable to each NTSC or
similar video downstream cable television channel in the system:
(1)(i) The cable television channels delivered to the subscriber's
terminal shall be capable of being received and displayed by TV
broadcast receivers used for off-the-air reception of TV broadcast
signals, as authorized under part 73 of this chapter; and
(ii) Cable television systems shall transmit signals to subscriber
premises equipment on frequencies in accordance with the channel
allocation plan set forth in the Electronics Industries Association's
``Cable Television Channel Identification Plan, EIA IS-132, May 1994''
(EIA IS-132). This incorporation by reference was approved by the
Director of the Federal Register in accordance with 5 U.S.C. 522(a) and
1 CFR Part 51. Cable systems are required to use this channel allocation
plan for signals transmitted in the frequency range 54 MHz to 1002 MHz.
This incorporation by reference was approved by the Director of the
Federal Register in accordance with 5 U.S.C. 522(a) and 1 CFR Part 51.
Copies of EIA IS-132 may be obtained from: Global Engineering Documents,
2805 McGraw Ave., Irvine CA 92714. Copies of EIA IS-132 may be inspected
during normal business hours at the following locations: Federal
Communications Commission, 1919 M Street, NW, Dockets Branch (Room 239),
Washington, DC, or the Office of the Federal Register, 800 North Capitol
Street, NW., suite 700, Washington, DC. This requirement is applicable
on May 31, 1995, for new and re-built cable systems, and on June 30,
1997, for all cable systems.
(2) The aural center frequency of the aural carrier must be 4.5 MHz
&177; 5 kHz above the frequency of the visual carrier at the
output of the modulating or processing equipment of a cable television
system, and at the subscriber terminal.
(3) The visual signal level, across a terminating impedance which
correctly matches the internal impedance of the cable system as viewed
from the subscriber terminal, shall not be less than 1 millivolt across
an internal impedance of 75 ohms (0 dBmV). Additionally, as measured at
the end of a 30 meter (100 foot) cable drop that is connected to the
subscriber tap, it shall not be less than 1.41 millivolts across an
internal impedance of 75 ohms (+3 dBmV). (At other impedance values, the
minimum visual signal level, as viewed from the subscriber terminal,
shall be the square root of 0.0133 (Z) millivolts and, as measured at
the end of a 30 meter (100 foot) cable drop that is connected to the
subscriber tap, shall be 2 times the square root of 0.00662(Z)
millivolts, where Z is the appropriate impedance value.)
(4) The visual signal level on each channel, as measured at the end
of a 30 meter cable drop that is connected to the subscriber tap, shall
not vary more than 8 decibels within any six-month interval, which must
include four tests performed in six-hour increments during a 24-hour
period in July or August and during a 24-hour period in January or
February, and shall be maintained within:
(i) 3 decibels (dB) of the visual signal level of any visual carrier
within a 6 MHz nominal frequency separation;
(ii) 10 dB of the visual signal level on any other channel on a
cable television system of up to 300 MHz of cable distribution system
upper frequency limit, with a 1 dB increase for each additional 100 MHz
of cable distribution system upper frequency limit (e.g., 11
[[Page 550]]
dB for a system at 301-400 MHz; 12 dB for a system at 401-500 MHz,
etc.); and
(iii) A maximum level such that signal degradation due to overload
in the subscriber's receiver or terminal does not occur.
(5) The rms voltage of the aural signal shall be maintained between
10 and 17 decibels below the associated visual signal level. This
requirement must be met both at the subscriber terminal and at the
output of the modulating and processing equipment (generally the
headend). For subscriber terminals that use equipment which modulate and
remodulate the signal (e.g., baseband converters), the rms voltage of
the aural signal shall be maintained between 6.5 and 17 decibels below
the associated visual signal level at the subscriber terminal.
(6) The amplitude characteristic shall be within a range of
&177;2 decibels from 0.75 MHz to 5.0 MHz above the lower boundary
frequency of the cable television channel, referenced to the average of
the highest and lowest amplitudes within these frequency boundaries.
(i) Prior to December 30, 1999, the amplitude characteristic may be
measured after a subscriber tap and before a converter that is provided
and maintained by the cable operator.
(ii) As of December 30, 1999, the amplitude characteristic shall be
measured at the subscriber terminal.
(7) The ratio of RF visual signal level to system noise shall be as
follows:
(i) From June 30, 1992, to June 30, 1993, shall not be less than 36
decibels.
(ii) From June 30, 1993 to June 30, 1995, shall not be less than 40
decibels.
(iii) As of June 30, 1995, shall not be less then 43 decibels.
(iv) For class I cable television channels, the requirements of
paragraphs (a)(7)(i), (a)(7)(ii) and (a)(7)(iii) of this section are
applicable only to:
(A) Each signal which is delivered by a cable television system to
subscribers within the predicted Grade B contour for that signal;
(B) Each signal which is first picked up within its predicted Grade
B contour;
(C) Each signal that is first received by the cable television
system by direct video feed from a TV broadcast station, a low power TV
station, or a TV translator station.
(8) The ratio of visual signal level to the rms amplitude of any
coherent disturbances such as intermodulation products, second and third
order distortions or discrete-frequency interfering signals not
operating on proper offset assignments shall be as follows:
(i) The ratio of visual signal level to coherent disturbances shall
not be less than 51 decibels for noncoherent channel cable television
systems, when measured with modulated carriers and time averaged; and
(ii) The ratio of visual signal level to coherent disturbances which
are frequency-coincident with the visual carrier shall not be less than
47 decibels for coherent channel cable systems, when measured with
modulated carriers and time averaged.
(9) The terminal isolation provided to each subscriber terminal:
(i) Shall not be less than 18 decibels. In lieu of periodic testing,
the cable operator may use specifications provided by the manufacturer
for the terminal isolation equipment to meet this standard; and
(ii) Shall be sufficient to prevent reflections caused by open-
circuited or short-circuited subscriber terminals from producing visible
picture impairments at any other subscriber terminal.
(10) The peak-to-peak variation in visual signal level caused by
undesired low frequency disturbances (hum or repetitive transients)
generated within the system, or by inadequate low frequency response,
shall not exceed 3 percent of the visual signal level. Measurements made
on a single channel using a single unmodulated carrier may be used to
demonstrate compliance with this parameter at each test location.
(11) As of June 30, 1995, the following requirements apply to the
performance of the cable television system as measured at the output of
the modulating or processing equipment (generally the headend) of the
system:
(i) The chrominance-luminance delay inequality (or chroma delay),
which is
[[Page 551]]
the change in delay time of the chrominance component of the signal
relative to the luminance component, shall be within 170 nanoseconds.
(ii) The differential gain for the color subcarrier of the
television signal, which is measured as the difference in amplitude
between the largest and smallest segments of the chrominance signal
(divided by the largest and expressed in percent), shall not exceed
&177;20%.
(iii) The differential phase for the color subcarrier of the
television signal which is measured as the largest phase difference in
degrees between each segment of the chrominance signal and reference
segment (the segment at the blanking level of O IRE), shall not exceed
&177;10 degrees.
(12) As an exception to the general provision requiring measurements
to be made at subscriber terminals, and without regard to the type of
signals carried by the cable television system, signal leakage from a
cable television system shall be measured in accordance with the
procedures outlined in Sec. 76.609(h) and shall be limited as follows:
------------------------------------------------------------------------
Signal
leakage
Frequencies limit Distance in
(micro-volt/ meters (m)
meter)
------------------------------------------------------------------------
Less than and including 54 MHz, and over 216
MHz.......................................... 15 30
Over 54 up to and including 216 MHz........... 20 3
------------------------------------------------------------------------
(b) Cable television systems distributing signals by using methods
such as nonconventional coaxial cable techniques, noncoaxial copper
cable techniques, specialized coaxial cable and fiber optical cable
hybridization techniques or specialized compression techniques or
specialized receiving devices, and which, because of their basic design,
cannot comply with one or more of the technical standards set forth in
paragraph (a) of this section, may be permitted to operate: Provided,
That an adequate showing is made pursuant to Sec. 76.7 which establishes
that the public interest is benefited. In such instances, the Commission
may prescribe special technical requirements to ensure that subscribers
to such systems are provided with an equivalent level of good quality
service.
Note 1: Local franchising authorities of systems serving fewer than
1000 subscribers may adopt standards less stringent than those in
Sec. 76.605(a). Any such agreement shall be reduced to writing and be
associated with the system's proof-of-performance records.
Note 2: For systems serving rural areas as defined in Sec. 76.5, the
system may negotiate with its local franchising authority for standards
less stringent than those in Secs. 76.605(a)(3), 76.605(a)(7),
76.605(a)(8), 76.605(a)(10) and 76.605(a)(11). Any such agreement shall
be reduced to writing and be associated with the system's proof-of-
performance records.
Note 3: The requirements of this section shall not apply to devices
subject to the provisions of Secs. 15.601 through 15.626.
Note 4: Should subscriber complaints arise from a system failing to
meet Sec. 76.605(a)(6) prior to December 30, 1999, the cable operator
will be required to provide a converter that will allow the system to
meet the standard immediately at the complaining subscriber's terminal.
Further, should the problem be found to be system-wide, the Commission
may order all converters on the system be changed to meet the standard.
Note 5: Should subscriber complaints arise from a system failing to
meet Sec. 76.605(a)(10), the cable operator will be required to remedy
the complaint and perform test measurements on Sec. 76.605(a)(10)
containing the full number of channels as indicated in Sec. 76.601(c)(2)
at the complaining subscriber's terminal. Further, should the problem be
found to be system-wide, the Commission may order that the full number
of channels as indicated in Sec. 76.601(c)(2) be tested at all required
locations for future proof-of-performance tests.
Note 6: No State or franchising authority may prohibit, condition,
or restrict a cable system's use of any type of subscriber equipment or
any transmission technology.
[ 37 FR 3278 , Feb. 12, 1972, as amended at 37 FR 13867 , July 14, 1972; 40 FR 2690 , Jan. 15, 1975; 40 FR 3296 , Jan. 21, 1975; 41 FR 53028 , Dec. 3,
1976; 42 FR 21782 , Apr. 29, 1977; 47 FR 21503 , May 18, 1982; 50 FR 52466 , Dec. 24, 1985; 51 FR 1255 , Jan. 10, 1986; 52 FR 22461 , June 12,
1987; 57 FR 11002 , Apr. 1, 1992; 57 FR 61010 , Dec. 23, 1992; 58 FR 44952 , Aug. 25, 1993; 59 FR 25342 , May 16, 1994; 61 FR 18510 , Apr. 26,
1996; 61 FR 18978 , Apr. 30, 1996]
Goto Section: 76.601 | 76.606
Goto Year: 1996 |
1998
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