Technical Standards and Operating Requirements for FM Broadcasting Stations in the Philippines (1991 Revised Edition) By: Technical Standards Committee of the Kapisanan ng mga Brodkaster sa Pilipinas Arcadio Carandang, Jr. --- Chairman Leoncio Galang --- Vice-Chairman Carlos Saliuan, Jr. --- NTC Representative Alfredo Ceralde --- Member Romualdo Lintag --- Member Salvador Castillo --- Member Filomeno Babas --- Member Ernesto Claudio --- Member Rolando Agbay --- Member Endorsed by: MIGUEL C. ENRIQUEZ Chairman – Kapisanan ng mga Brodkaster ng Pilipinas ANDRE S. KAHN President – Kapisanan ng mga Brodkaster ng Pilipinas Approved by:
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Technical Standards and Operating Requirements for FM
Broadcasting Stations in the Philippines (1991 Revised Edition)
By:
Technical Standards Committee of the Kapisanan ng mga Brodkaster sa
Pilipinas
Arcadio Carandang, Jr. --- Chairman
Leoncio Galang --- Vice-Chairman
Carlos Saliuan, Jr. --- NTC Representative
Alfredo Ceralde --- Member
Romualdo Lintag --- Member
Salvador Castillo --- Member
Filomeno Babas --- Member
Ernesto Claudio --- Member
Rolando Agbay --- Member
Endorsed by:
MIGUEL C. ENRIQUEZ
Chairman – Kapisanan ng mga Brodkaster ng Pilipinas
ANDRE S. KAHN
President – Kapisanan ng mga Brodkaster ng Pilipinas
Approved by:
MARIANO E. BENEDICTO II
Commissioner – National Telecommunication Commission
CONTENTS OF FM BROADCASTING
Section
1. Introduction
2. Definition of Terms
3. Allocation of Frequencies for FM Broadcast Stations
4. Classes of FM Broadcast Stations
5. Technical Requirements
6. Broadcast Auxiliary Services
7. Operating Requirements
8. FM Broadcast Translators and Signal Boosters
9. Public Information File
10. Annexes
FM BROADCAST STANDARDS
1. INTRODUCTION
The increasing Importance of the role of FM broadcasting in the
Philippines has encouraged broadcast engineers and the National
Telecommunications Commission to pool their resources together and come
up with technical standards and rules and regulations relating to FM
broadcast.
These technical standards and regulations were derived from CCIR
recommendations, relevant engineering data and rules and regulations of
the Federal Communications Corn- mission, and other data supplied by
manufacturers of radio equipment and by licensees of FM broadcast stations.
These standards and regulations shall be revised from time to time to be
effective and compatible with technical progress.
2. DEFINITION OF TERMS
2.1 FM broadcast band
That portion of the radio frequency spectrum from 88 MHz to 108 MHz.
The band is divided into 100 channels.
2.2 FM broadcast channel
A band of frequencies 200 kilohertz wide and is designated by its
center frequency. Channels for FM broadcast stations begin at 82.1
megahertz and continue in successive steps of 200 kilohertz to and including
107.9 megahertz.
2.3 FM broadcast station
A station employing frequency modulation in the FM broadcast band
and intended to be received by the general public.
2.4 Frequency Modulation
A system of modulation where the instantaneous frequency varies in
proportion to the instantaneous amplitude of the modulating signal, and the
instantaneous radio frequency is independent of the frequency of the
modulating signal.
2.5 Center frequency
The carrier frequency allocated by the Authority.
2.6 Frequency Swing
The instantaneous departure of the frequency of the emitted wave
from the center frequency resulting from modulation.
2.7 Antenna height above average terrain (HAAT) means
a. The height of the radiation center of the antenna above the
terrain 3 to 16 kilometres from the antenna. (Generally, a different
antenna height will be determined for each radial direction from the
antenna. The average of these various heights is considered as the
antenna height above average terrain).
b. Where circular or elliptical polarization is employed the
antenna height above average terrain shall be based upon the height
of the radiation center of the antenna which transmits the horizontal
components of radiation.
2.8 Antenna field gain
The ratio of the effective free space field intensity produced at 1.6
kilometres in the horizontal plane expressed in millivolts per meter for one
(1) kilowatt antenna input power, to 137.6 millivolts per meter.
2.9 Antenna power gain
The square of the ratio of the root- mean-square free space field
strength produced at 1.6 kilometers in the horizontal plane, in millivolts per
meter for one (1) kilowatt antenna power, to 137.6 millivolts per meter. This
ratio should be expressed in decibels (dB). (If specified for a particular
direction, antenna power gain is based on the field strength in that direction
only).
2.10 Effective radiated power (ERP)
The product of the transmitter power (transmitter output power less
transmission line loss) multiplied by (a) the antenna power gain or (b) the
antenna field gain squared. Where circular or elliptical polarization is
employed, the term “effective radiated power” is applied separately to the
horizontal and vertical components of radiation.
2.11 Field intensity
“Field intensity” as used in these standards shall mean the electric
field intensity in the horizontal direction.
2.12 Free space field intensity
The field intensity that would exist at a point, in the absence of waves
reflected from the earth or other reflecting objects.
2.13 Service area
As applied to FM broadcasting, means the service resulting from an
assigned effective radiated power and antenna height above average terrain.
2.14 Radio-frequency (R .F.) Protection Ratio
The value of the radio-frequency wanted-to-interfering signal ratio that
enables, under specified conditions, the radio-frequency protection ratio to
be obtained at the output of a receiver.
2.15 Percentage modulation
The ratio of the actual frequency swing to the frequency swing defined
as 100 percent modulation, expressed in percentage. For FM broadcasting
stations, a frequency swing of 75 kilohertz is defined as 100 percent
modulation.
2.16 Multiplexing
In its simplest sense, multiplexing implies that two or more
independent sources of information are combined for carriage over a single
medium, namely, the radio frequency “carrier”, and then are separated at
the receiving end. In stereophonic broadcasting, for example, program
information consisting of left and right audio signals are multiplexed onto an
FM carrier for transmission to receivers which subsequently recover the
original audio signals.
2.17 FM Stereophonic Broadcast
The transmission of a stereophonic program by a single FM broadcast
station utilizing the main channel and a stereophonic sub-channel.
2.18 Channel
A transmission path. The distinction between the concept of a
“Channel” and a “signal” are not always clear. The usage herein
distinguishes between transmission channels; e.g., main channel,
stereophonic subchannel, etc., and left and right audio “signals”.
2.19 Composite Baseband Signal
A signal which is the sum of all signals which frequency-modulates the
main carrier. The signal can be represented by a formula which includes all
signal components: the main channel signal, the modulated stereophonic
subcarrier, the pilot subcarrier and the SCA subcarrier(s).
2.20 FM Baseband
The frequency band from 0 Hertz (Hz) to a specified upper frequency
which contains the composite baseband signal.
2.21 Main Channel
The band of frequencies from 50 (or less) Hz to 15,000 Hz on the FM
baseband which contains the main channel signal.
2.22 Main Channel Signal
A specified combination of the mono phonic or left and right audio
signals which frequency-modulates the main carrier.
2.23 Stereophonic Sound
The audio information carried by plurality of channels arranged to
afford the listener a sense of the spatial distribution of sound sources.
Stereophonic sound includes, but is not limited to, biphonic (two channel),
triphonic (three channel) and quadrophonic (four channel) services.
2.24 Stereophonic Sound Subcarrier
A subcarrier within the FM broadcast baseband used for transmitting
signals for stereophonic sound reception of the main broadcast program
service.
2.25 Stereophonic Sound Subchannel
The band of frequencies from 23 2.34 Cross-talk kHz to 99 KHz
containing sound subcarriers and their associated sidebands.
2.26 Subchannel
A transmission path specified by a subchannel signal occupying a
specified band of frequencies.
2.27 Subchannel Signal
Subcarrier(s) and associated sideband(s) which frequency-modulate
the main carrier. It is synonymous with “subcarrier”, as in the stereophonic
subcarrier or SCA subcarrier.
2.28 Pilot sub-carrier
A pilot sub-carrier serving as a control signal for use in the reception of
FM stereophonic broadcast.
2.29 Left (or Right) signal
The electrical output of a microphone of a combination of microphones
placed so as to convey the intensity, time, and location of sounds originating
predominantly to the listener’s left (or right) of the center of the performing
area.
2.30 Left (or Right) stereophonic channel
The left (or right) signal as electrically reproduced in the reception of
an FM stereophonic broadcast.
2.31 Stereophonic separation
The ratio of the electrical signal caused in the right (or left)
stereophonic channel, to the electrical signal caused in the left (or right)
stereophonic channel, by the transmission of only a right (or left) signal.
2.32 Frequency Deviation
The peak difference between the instantaneous frequency of the
modulated wave and the carrier frequency.
2.33 Injection Ratio
The ratio of the frequency swing of the FM carrier by a subchannel
signal to the frequency swing defined as 100 percent modulation, expressed
in percentage. The total injection of more than one subchannel signal is the
arithmetic sum of each subchannel.
2.34 Cross-talk
An undesired signal occuring in one channel caused by an electrical
signal in another channel.
2.35 Linear Crosstalk
A form of “crosstalk” in which the undesired signal(s) is created by
phase or gain inequalities in another channel or channels. Such crosstalk
may be due to causes external to the stereophonic generator consequently it
is sometimes referred to as “system crosstalk”.
2.36 Nonlinear Crosstalk
A form of crosstalk in which the undesired signal(s) is created by
harmonic distortion or inter-modulation of electrical signal(s) in another
channel or channels. Such crosstalk may be due to distribution within the
stereophonic generator or FM transmitter consequently it is sometimes
referred to as “transmitter crosstalk”.
2.37 SCA
The term SCA is an acronym for a “Subsidiary Communications
Authorization.”
2.38 Index of cooperation
As applied to facsimile broadcasting, is the product of the number of
lines per inch, the available length in inches, and the reciprocal of the line-
use ratio (e.g. 105 x 8.2 x 8/7 = 984).
2.39 Line-use ratio
As applied to facsimile broadcasting is the ratio of the available line to
the total length of scanning line.
2.40 Available line
Means the portion of the total length of scanning line that can be used
specifically for picture signals.
2.41 Rectilinear scanning
The process of scanning an area in a predetermined sequence of
narrow straight parallel strips.
2.42 Optical density
The logarithm (to the base 10) of the ratio of incident to transmitted or
reflected light.
Table 1. ALLOCATION OFFREQUENCIES FOR FM BROADCAST
STATIONS
Channel-designation of FM broadcast frequencies are shown in the table
below.
Channel No.
Frequency
(MHZ) Channel No.
Frequency
(MHZ)
201 88.1 251 98.1
202 88.3 252 98.3
203 88.5 253 98.5
204 88.7 254 98.7
205 88.9 255 98.9
206 89.1 256 99.1
207 89.3 257 99.3
208 89.5 258 99.5
209 89.7 259 99.7
210 89.9 260 99.9
211 90.1 261 100.1
212 90.3 262 100.3
213 90.5 263 100.5
214 90.7 264 100.7
215 90.9 265 100.9
216 91.1 266 101.1
217 91.3 267 101.3
218 91.5 268 101.5
219 91.7 269 101.7
220 91.9 270 101.9
221 92.1 271 102.1
222 92.3 272 102.3
223 92.5 273 102.5
224 92.7 274 102.7
225 92.9 275 102.9
226 93.1 276 103.1
227 93.3 277 103.3
228 93.5 278 103.5
229 93.7 279 103.7
230 93.9 280 103.9
231 94.1 281 104.1
232 94.3 282 104.3
233 94.5 283 104.5
234 94.7 284 104.7
235 94.9 285 104.9
236 95.1 286 105.1
237 95.3 287 105.3
238 95.5 288 105.5
239 95.7 289 105.7
240 95.9 290 105.9
241 96.1 291 106.1
242 96.3 292 106.3
243 96.5 293 106.5
244 96.7 294 106.7
245 96.9 295 106.9
246 97.1 296 107.1
247 97.3 297 107.3
248 97.5 298 107.5
249 97.7 299 107.7
250 97.9 300 107.9
2.43 Experimental Period
The period between 12 midnight to 5:00 a.m. local standard time
(1600-2100 (MT). This period may be used for experimental purposes in
testing and maintaining apparatus by the licensee of any FM broadcast
station on its assigned frequency and not in excess of its authorized power,
provided no interference is caused to other stations maintaining a regular
operating schedule within such period.
2.44 Operating Power
This is the product of the plate voltage (Ep) and the plate current(Ip) of
the last radio stage and efficiency factor, F, expressed: Operating Power =
Ep x Ip x F. This is the indirect method of determining the operating power of
each FM station for the purpose of specifying the operating power range of
FM transmitters. The factor F shall be established by the transmitter
manufacturer for each type of transmitter and shall be specified in the
instruction book (s) supplied to each customer with each transmitter.
2.45 Last radio stage
The oscillator or radio-frequency- power amplifier stage which supplies
power to the antenna.
2.46 Qualified technician
As applied to FM broadcasting means a person who is a holder of any
class of Radio Telephone Operator’s License or its equivalent except those
mentioned in Section 7.4 as issued by the existing regulatory body.
3. ALLOCATION OF FREQUENCIES FOR FM BROADCAST STATIONS
(See Table 1.)
4. CLASSES OF FM BROADCAST STATIONS
4.1 Class-A Stations
A Class-A station shall have an authorized transmitter power not
exceeding 25 kilowatts and an Effective Radiated Power (ERP) not
exceeding 125 kilowatts and limited in antenna height of 2,000 feet
above average terrain. The minimum transmitter power shall be 10KW.
Class A station shall only be allowed in Metro-Manila and Metro-Cebu.
4.2 Class-B station
A Class-B station shall have an authorized transmitter power not
exceeding 10 kilowatts and an Effective Radiated Power not exceeding
30 kilowatts, and limited in antenna height of 500 feet above average
terrain. The minimum transmitter power shall be I KW.
4.3 Class-C stations
A Class-C station is a non-commercial, community station having
an authorized radiated power not exceeding 1,000 watts (ERP).
4.4 Class—D Station
A class-D station shall have an authorized transmitter power not
exceeding 10 watts.
Educational stations shall be allowed to operate with Class- D
transmitter power.
4.5 All classes of FM stations shall be protected to the I mV/m
contour or 60 dBu contour.
4.6 Table of Assignments
The frequency assignments for the cities of Manila, Laoag, Legaspi, Cebu,
Davao, and Zamboanga shall be selected from table 2.
Table 2
Channel
Frequency
(MHz)
202 88.3
206 89.1
210 89.9
214 90.7
218 91.5
222 92.3
226 93.1
230 93.9
234 94.7
238 95.5
242 96.3
246 97.1
250 97.9
254 98.7
258 99.5
262 100.3
266 101.1
270 101.9
274 102.7
278 103.5
282 104.3
286 105.1
290 105.9
294 106.7
298 107.5
4.7 Radio Frequency Protection Ratios
4.7.1 The following radio frequency protection ratios (Table 3) provide
for the minimum physical separation between stations and protection
of stations from interference.
Table 3
RADIO-FREQUENCY PROTECTION RATIOS (dB)
(based on the horizontal component of radiation)
Frequency Spacing (KHz) R.F. Signal Ratio
0 60dBu : 15dBu
200 60dBu : 53dBu
400 60dBu : 80dBu
4.7.2 Intermediate frequency amplifiers of most FM broadcast
receivers are designed to operate on 10.7 mega Hertz. For this
reason the assignment of two stations in the same area, one with
a frequency 10.6 or 10.8 mega-Hertz removed from that of the
other, should be avoided if possible.
4.7.3 FM Broadcast Stations shall not be authorized to operate in
the same city or in nearby cities with a frequency separation of
less than 800 kHz.
4.7.4 The nature and extent of the protection from interference
accorded the FM broadcast stations is limited solely to that which
results from the application of the radio frequency protection
ratio.
4.7.5 A commercial broadcast entity may establish only one
primary FM radio station within the geographical boundaries of
any province.
5. Technical Requirements
5.1 Safety Requirements
5.1.1 Conformity with Electrical Wiring Rules
All equipment using electrical power shall conform with the
provisions of the Philippine Electrical Code and the Philippines
Electronics Code so as to ensure the safety of property,
equipment, personnel and the public in general.
5.1.2 All component parts shall be in accordance with
generally accepted standards or those of the International
Standards.
5.2 Transmitting Facilities
5.2.1 Location and Layout
a. Any site particularly suitable for FM broadcasting in an
area, in the absence of other comparable sites, may be shared
by and be made available to as many applicants as possible.
b. The transmitting site should be selected consistent with
the purpose of the station, i.e., whether it is intended to serve a
small city, a metropolitan area, or a large region. The location
should be so chosen that line-of-sight can be obtained from the
antenna over the principal city or cities to be served.
5.2.2 Antenna System
a. It shall be standard to employ horizontal polarization.
However, circular or elliptical polarization of the clockwise or
counter-clockwise rotation may be employed, if so desired.
b. The antenna must be constructed such that it is clear of
surrounding buildings or objects that would cause shadow
problems.
c. In the event a common tower is used by two or more
licensees for antenna and/or antenna supporting purposes, the
licensee who owns the tower shall assume full responsibility for
the maintenance of the tower structure, its painting and lighting
requirements. In case of shared ownership, only one licensee
shall assume such responsibility.
For the protection of air navigation, the antenna and supporting structure
shall be painted and illuminated in accordance with ATO regulations.
5.2.3 Transmitter and Associated Equipment
a. Electrical Performance Standards
The general design of the FM broadcast transmitting
system (from input terminal of microphone preamplifier,
through audio facilities at the studio through lines or other
circuits between studio and transmitter, through audio
facilities at the transmitter, and through the transmitter,
but excluding equalizers for the correction of deficiencies
in microphone response) shall be in accordance with the
following principles and specifications:
1) The transmitter shall operate satisfactorily in
the operating power range with a frequency swing of
±75 kilohertz, which is defined as 100 percent
modulation.
2) The transmitting system shall be capable of
transmitting a band of frequencies from 50 to 15,000
Hertz. Pre-emphasis shall be employed in accordance
with the impedance-frequency characteristics of a
series inductance-resistance network having a time
constant of 75 microseconds (See Annex Fig. 2). The
deviation of the system response from the standard
pre emphasis curve shall lie between two limits. The
upper of these limits shall be uniform: (no deviation)
from 50 to 15,000 Hertz. The lower limit shall be
uniform from 100 to 7,500 Hertz and 3 dB below the
upper limit; from 50 to 100 Hertz and the lower limit
shall fall from the 3 dB limit at a uniform rate of 1dB
per octave (4dB at 50 Hertz); from 7,500 to15,000
Hertz, the lower limit shall fall from the 3 dB limit at
a uniform rate of 2 dB per octave (5dB at 15,000
Hertz).
3) At any modulating frequency between 50
and 15,000 Hertz and at modulation percentages of
25, 50 and 100 percent, the combined audio
frequency harmonics measured in the output of the
system shall not exceed the root-mean- square
values given in the following table:
Modulator Frequency Distortion
50 to 100 Hz 3.50%
100 to 7500 Hz 2.50%
7,500 to 15,000 Hz 3.00%
4) Measurements shall be made employing a
75- microsecond de-emphasis in the measuring
equipment and 75-microsecond pre-emphasis in the
transmitting equipment, and without compression, if
a compression amplifier is employed. Harmonics
shall be included to 30,000 Hertz.
5) It is recommended that none of the three
main divisions of the system (transmitter, studio to
transmitter circuit, and audio facilities) contribute
over one-half of these percentages since at some
frequencies the total distortion may become the
arithmetic sum of the distortion of the divisions.
6) The transmitting system output noise level
(frequency modulation) in the band of 50 to 15,000
Hertz shall be at least 60 decibels below 100 percent
modulation (frequency swing of ±75 kilohertz).
The measurement shall be made using 400
Hertz modulation as a reference. The noise
measuring equipment shall be provided with a
standard 75- microsecond de-emphasis; the ballistic
characteristic of the instrument shall be similar to
those of the standard VU meter.
7) The transmitting system output noise level
(amplitude modulation) in the band of 50 to 16,000
Hertz shall be at least 50 decibels below the level
representing 100 percent amplitude modulation. The
noise-measuring equipment shall be provided with a
standard 75 microsecond de-emphasis; and the
ballistic characteristics of the instrument shall be
similar to those of the standard VU meter.
8) Automatic means shall be provided in the
transmitter to maintain the assigned center
frequency within the allowable tolerance of (± 2000
Hertz).
9) The transmitter shall be equipped with
suitable indicating instruments for the determination
of operating power and with other instruments as are
necessary for proper adjustments, operation, and
maintenance of the equipment.
10) Adequate provision shall be made for
varying the transmitter output power to compensate
for excessive variations in line voltage or for other
factors affecting the output power.
11) Allowances shall be provided in all
component parts to avoid overheating at the rated
maximum output power.
12) If a limiting or compression amplifier is
employed, precaution should be maintained in its
connection in the circuit due to the use of pre-
emphasis in the transmitting system.
13) Any emission appearing on a frequency
removed from the carrier by between 120 kHz, and
240 kHz, inclusive, shall be attenuated at least 25
decibels below the level of the un-modulated carrier.
14) Any emission appearing on a frequency
removed from the carrier by more than 240 kHz and
up to and including 600 kHz shall be attenuated at
least 35 db below the level of the unmodulated
carrier.
15) Any emission appearing on a frequency
removed from the carrier by more than 600 kHz shall
be attenuated at least 43+ 10 Log10 (Power, in
watts) decibels below the level of the unmodulated
carrier, or 80 decibels, whichever is the lesser
attenuation.
b. Construction
In general, the transmitter shall be constructed either on
racks and panels or in totally en-closed frames protected as
required by the Philippine Electronics Code and the Philippine
Electrical Code and those set forth below:
The transmitter shall comply with the following:
1) Enclosure. The transmitter shall be enclosed in a metal
frame or grille, or separated from the operating space by a
barrier or other equivalent means. All metallic parts shall be
connected to ground.
2) Grounding of controls. All external metallic handles and
controls accessible to the operating personnel shall be effectively
grounded. No circuit in excess of 100 volts shall have any part
exposed to direct contact. A complete dead front type of
switchboard is preferred.
3) Interlocks on doors.
a) All access doors shall be provided with interlocks
which will disconnect all voltages in excess of 350 volts
when any access door is opened.
b) Means shall be provided for making all tuning
adjustment, requiring voltages in excess of 350 volts to be
applied to the circuit, from the front of the panels with all
access doors closed.
c) Proper bleeder resistors or other automatic means
shall be installed across all capacitor banks to lower any
voltage which may remain accessible with access door
open to less than 350 volts within 2 seconds after the
access door is opened.
d) All plate supply and other high voltage equipment,
including transformers, filters, rectifiers and motor
generators, shall be protected so as to prevent injury to
operating personnel.
e) Power equipment and control panels of the
transmitter shall meet the above requirements exposed
220 volts AC switching equipment on the front of the
power control panels is not recommended
c. Wiring and Shielding
1) The transmitter panels or units shall be wired in
accordance with standard switchboard practice, either with
insulated leads properly cabled and supported or with rigid bus
bar properly insulated and protected.
2) Wiring between units of the transmitter, with the
exception of circuits carrying radio-frequency energy, shall be
installed in conduits or approved fiber or metal raceways e.
Indicating instruments for protection from mechanical injury.
3) Circuits carrying radio- frequency energy between units
shall be coaxial, or two-wire balanced lines, or properly shielded.
4) All stages or units shall be adequately shielded and
filtered to prevent interaction and radiation.
d. Metering equipment
1) All instruments having more than 1,000 volts potential
to ground on the movements shall be protected by a cage or
cover. (some instruments are designed by the manufacturer to
operate safely with voltages in excess of 1,000 volts on the
movement).
2) In case the plate voltmeter is located on the low
potential side of the multiplier resistor with the potential of the
high potential terminal to the instrument at or less than 1,000
volts above ground, no protective case is required. However, it is
good practice to protect voltmeters subject to more than 5,000
volts with suitable over-voltage protective device(s) across the
instrument terminal in case the winding opens.
3) Transmission line meters and any other radiofrequency
instrument which may be necessary for the operator to read,
shall be so installed as to be easily and accurately read without
the operator having to risk contact with circuits carrying high
potential radio-frequency energy.
e. Indicating Instruments
1) Each FM broadcast station shall be equipped with
indicating instruments for measuring the direct plate voltage and
current of the last radio stage and the transmission line radio
frequency power.
2) In the event that the plate voltmeter or plate ammeter
in the last radio stage is defective, the operating power shall be
maintained by means of the radio-frequency power meter.
f. Installation
1) The installation shall be made in suitable quarters.
2) Since an operator must be on duty at the transmitter
control during operation, suitable facilities for his welfare and
comfort shall be provided at the control point.
g. Other technical data.
An accurate circuit diagram, as furnished by the
manufacturer of the equipment, shall be retained at the
transmitter location.
5.2.4 Monitoring Equipment
a. Frequency Monitor
1) The licensee of each station shall have in operation,
either at the transmitter or at the place where the transmitter is
controlled, a frequency monitor of a type approved by the
Commission which shall be independent of the frequency control
of the transmitter.
2) In the event that the frequency monitor becomes
defective, the station may be operated without such equipment
pending its repair or replacement for a period not in excess of 60
days without further authority of the Commission: Provided,
That:
a) Appropriate entries shall be made in the operation
log of the station to show the date and time the monitor
was removed from and restored to service.
b) The Engineer in Charge of the Region in which the
station is located shall be notified both immediately after
the monitor is found to be defective and immediately after
the repaired or replacement monitor has been installed
and is functioning properly.
c) The frequency of the station shall be compared
with an external frequency source of known accuracy at
sufficiently frequent intervals to insure that the frequency
is maintained within the tolerance. An entry shall be made
in the station log as to the method used and the results
thereof.
3) If conditions beyond the control of the licensee or
permittee prevent the restoration of the monitor to service within
the above allowed period, informal request may be filed with the
Engineer in Charge of the Region in which the station is located
for such additional time as may be required to complete re pairs
of the defective instrument or equipment.
Modulation Monitor
The modulation monitor (deviation monitor) Is an optional requirement
for an FM station. The FM station may refer to the monitoring section of the
Authority, to the Standards Authority of the KP or to other FM stations for
modulation measurements.
5.3. Stereophonic Transmission Standards
a. The modulating signal for the main channel shall consist of the sum
of the left and right signals.
b. A pilot subcarrier at 19,000 Hertz plus or minus 2 Hz, shall be
transmitted that shall frequency-modulate the main carrier between
the limits of 8 and 10 percent.
c. The stereophonic subcarrier shall be the second harmonic of the
pilot subcarrier and shall cross the time axis with a positive slope
simultaneously with each crossing of time axis by the pilot subcarrier.
d. Amplitude modulation of the stereophonic subcarrier shall be used.
e. The stereophonic subcarrier shall be suppressed to a level less than
one percent modulation of the main carrier.
f. The stereophonic subcarrier shall be capable of accepting audio
frequencies from 50 to 15,000 Hz.
g. The modulating signal for the stereophonic subcarrier shall be equal
to the difference of the left and right signals.
h. The pre-emphasis characteristics of the stereophonic subchannel
shall be identical with those of the main channel with respect to phase
and amplitude at all frequencies.
i. The sum of the side bands resulting from amplitude modulation of
the stereophonic subcarrier shall not cause a peak deviation of the
main carrier in excess of 45 percent of total modulation (excluding SCA
subcarriers) when only a left (or right) signal exists; simultaneously in
the main channel, the deviation when only a left (or right) signal exists
shall not exceed 45 percent of total modulation (excluding SCA
subcarriers).
j. The maximum modulation of the main carrier by all SCA subcarriers
shall be limited to 10 percent.
k. At the instant when only a positive left signal is applied, the main
channel modulation shall cause an upward deviation of the main
carrier frequency; and the stereophonic subcarrier and its sidebands
signal shall cross the time axis simultaneously and in the same
direction.
l. The ratio of peak main channel deviation to peak stereophonic
subchannel deviation, when only a steady state left (or right) signal
exists, shall be within plus or minus 3.5 percent of unity for all levels of
this signal and all frequencies from 50 to 15,000 Hertz.
m. The phase difference between the zero points of the main channel
signal and the stereophonic subcarrier sidebands envelope, when only
a steady state left (or right) signal exists, shall not exceed plus or
minus 3 degrees for audio modulating frequencies from 50 to 15,000
Hz.
Note: If the stereophonic separation between left and right
stereophonic channels is better than 29.7 decibels at audio modulating
frequencies between 50 to 15,000 Hz it will be assumed that (I) and
(m) of this section have been complied with.
n. Cross- talk into the main channel caused by a signal in the
stereophonic subchannel shall be attenuated at least 40 decibels
below 90 percent modulation.
o. Cross-talk into the stereophonic subchannel caused by a signal inthe
main channel shall be attenuated at least 40 decibels below 90 percent
modulation.
p. For required transmitter performance the maximum modulation to
be employed is 90 percent (excluding pilot subcarrier) rather than 100
percent.
q. For electrical performance standards of the transmitter and
associated equipment, 100 percent modulation is referred to include
the pilot subcarrier.
5.4 Subsidiary Communications Authorization (SCA)
5.4.1 Permissible uses of the SCA must fall within one or both of
the following categories:
a. Transmission of programs which are of a broadcast
nature, but which are of interest primarily to limited segments of
the public wishing to subscribe thereto. Illustrative services