Goto Section: 90.542 | 90.547 | Table of Contents
FCC 90.543
Revised as of October 1, 2019
Goto Year:2018 |
2020
§ 90.543 Emission limitations.
Transmitters designed to operate in 769-775 MHz and 799-805 MHz
frequency bands must meet the emission limitations in paragraphs (a)
through (d) of this section. Class A and Class B signal boosters
retransmitting signals in the 769-775 MHz and 799-805 MHz frequency
bands are exempt from the limits listed in paragraph (a) of this
section when simultaneously retransmitting multiple signals and instead
shall be subject to the limit listed in paragraph (c) of this section
when operating in this manner. Transmitters operating in 758-768 MHz
and 788-798 MHz bands must meet the emission limitations in (e) of this
section.
(a) The adjacent channel power (ACP) requirements for transmitters
designed for various channel sizes are shown in the following tables.
Mobile station requirements apply to handheld, car mounted and control
station units. The tables specify a value for the ACP as a function of
the displacement from the channel center frequency and measurement
bandwidth. In the following tables, “(s)” indicates a swept measurement
may be used.
6.25 kHz Mobile Transmitter ACP Requirements
Offset from center
frequency
(kHz) Measurement bandwidth
(kHz) Maximum ACP relative
(dBc)
6.25 6.25 −40
12.5 6.25 −60
18.75 6.25 −60
25.00 6.25 −65
37.50 25.00 −65
62.50 25.00 −65
87.50 25.00 −65
150.00 100.00 −65
250.00 100.00 −65
350.00 100.00 −65
>400 kHz to 12 MHz 30 (s) −75
12 MHz to paired receive band 30 (s) −75
In the paired receive band 30 (s) −100
12.5 kHz Mobile Transmitter ACP Requirements
Offset from center
frequency
(kHz) Measurement bandwidth
(kHz) Maximum ACP relative
(dBc)
9.375 6.25 −40
15.625 6.25 −60
21.875 6.25 −60
37.50 25.00 −60
62.50 25.00 −65
87.50 25.00 −65
150.00 100 −65
250.00 100 −65
350.00 100 −65
>400 to 12 MHz 30 (s) −75
12 MHz to paired receive band 30 (s) −75
In the paired receive band 30 (s) −100
25 kHz Mobile Transmitter ACP Requirements
Offset from center
frequency
(kHz) Measurement bandwidth
(kHz) Maximum ACP relative
(dBc)
15.625 6.25 −40
21.875 6.25 −60
37.50 25 −60
62.50 25 −65
87.50 25 −65
150.00 100 −65
250.00 100 −65
350.00 100 −65
>400 kHz to 12 MHz 30 (s) −75
12 MHz to paired receive band 30 (s) −75
In the paired receive band 30 (s) −100
6.25 kHz Base Transmitter ACP Requirements
Offset from center
frequency
(kHz) Measurement bandwidth
(kHz) Maximum ACP
(dBc)
6.25 6.25 −40
12.50 6.25 −60
18.75 6.25 −60
25.00 6.25 −65
37.50 25 −65
62.50 25 −65
87.50 25 −65
150.00 100 −65
250.00 100 −65
350.00 100 −65
>400 to 12 MHz 30 (s) −80
12 MHz to paired receive band 30 (s) −80
In the paired receive band 30 (s) ^1-85
^1Although we permit individual base transmitters to radiate a maximum
ACP of −85 dBc in the paired receive band, licensees deploying these
transmitters may not exceed an ACP of −100 dBc in the paired receive
band when measured at either the transmitting antenna input port or the
output of the transmitter combining network. Consequently, licensees
deploying these transmitters may need to use external filters to comply
with the more restrictive ACP limit.
12.5 kHz Base Transmitter ACP Requirements
Offset from center
frequency
(kHz) Measurement bandwidth
(kHz) Maximum ACP
(dBc)
9.375 6.25 −40
15.625 6.25 −60
21.875 6.25 −60
37.5 25 −60
62.5 25 −65
87.5 25 −65
150 100 −65
250 100 −65
350.00 100 −65
>400 kHz to 12 MHz 30 (s) −80
12 MHz to paired receive band 30 (s) −80
In the paired receive band 30 (s) ^1-85
^1Although we permit individual base transmitters to radiate a maximum
ACP of −85 dBc in the paired receive band, licensees deploying these
transmitters may not exceed an ACP of −100 dBc in the paired receive
band when measured at either the transmitting antenna input port or the
output of the transmitter combining network. Consequently, licensees
deploying these transmitters may need to use external filters to comply
with the more restrictive ACP limit.
25 kHz Base Transmitter ACP Requirements
Offset from center
frequency
(kHz) Measurement bandwidth
(kHz) Maximum ACP
(dBc)
15.625 6.25 −40
21.875 6.25 −60
37.5 25 −60
62.5 25 −65
87.5 25 −65
150 100 −65
250 100 −65
350 100.00 −65
>400 kHz to 12 MHz 30 (s) −80
12 MHz to paired receive band 30 (s) −80
In the paired receive band 30 (s) ^1-85
^1Although we permit individual base transmitters to radiate a maximum
ACP of −85 dBc in the paired receive band, licensees deploying these
transmitters may not exceed an ACP of −100 dBc in the paired receive
band when measured at either the transmitting antenna input port or the
output of the transmitter combining network. Consequently, licensees
deploying these transmitters may need to use external filters to comply
with the more restrictive ACP limit.
(b) ACP measurement procedure. The following are the procedures for
making the transmitter ACP measurements. For all measurements modulate
the transmitter as it would be modulated in normal operating
conditions. For time division multiple access (TDMA) systems, the
measurements are to be made under TDMA operation only during time slots
when the transmitter is active. All measurements are made at the
transmitter's output port. If a transmitter has an integral antenna, a
suitable power coupling device shall be used to couple the RF signal to
the measurement instrument. The coupling device shall substantially
maintain the proper transmitter load impedance. The ACP measurements
may be made with a spectrum analyzer capable of making direct ACP
measurements. “Measurement bandwidth”, as used for non-swept
measurements, implies an instrument that measures the power in many
narrow bandwidths equal to the nominal resolution bandwidth and
integrates these powers to determine the total power in the specified
measurement bandwidth.
(1) Setting reference level. Set transmitter to maximum output power.
Using a spectrum analyzer capable of ACP measurements, set the
measurement bandwidth to the channel size. For example, for a 6.25 kHz
transmitter set the measurement bandwidth to 6.25 kHz. Set the
frequency offset of the measurement bandwidth to zero and adjust the
center frequency of the instrument to the assigned center frequency to
measure the average power level of the transmitter. Record this power
level in dBm as the “reference power level.”
(2) Non-swept power measurement. Using a spectrum analyzer capable of
ACP measurements, set the mesurement bandwidth and frequency offset
from the assigned center frequency as shown in the tables in § 90.543
(a) above. Any value of resolution bandwidth may be used as long as it
does not exceed 2 percent of the specified measurement bandwidth.
Measure the power level in dBm. These measurements should be made at
maximum power. Calculate ACP by substracting the reference power level
measured in (b)(1) from the measurements made in this step. The
absolute value of the calculated ACP must be greater than or equal to
the absolute value of the ACP given in the table for each condition
above.
(3) Swept power measurement. Set a spectrum analyzer to 30 kHz
resolution bandwidth, 1 MHz video bandwidth and average, sample, or RMS
detection. Set the reference level of the spectrum analyzer to the RMS
value of the transmitter power. Sweep above and below the carrier
frequency to the limits defined in the tables. Calculate ACP by
substracting the reference power level measured in (b)(1) from the
measurements made in this step. The absolute value of the calculated
ACP must be greater than or equal to the absolute value of the ACP
given in the table for each condition above.
(c) Out-of-band emission limit. On any frequency outside of the
frequency ranges covered by the ACP tables in this section, the power
of any emission must be reduced below the mean output power (P) by at
least 43 + 10log (P) dB measured in a 100 kHz bandwidth for frequencies
less than 1 GHz, and in a 1 MHz bandwidth for frequencies greater than
1 GHz.
(d) Authorized bandwidth. Provided that the ACP requirements of this
section are met, applicants may request any authorized bandwidth that
does not exceed the channel size.
(e) For operations in the 758-768 MHz and the 788-798 MHz bands, the
power of any emission outside the licensee's frequency band(s) of
operation shall be attenuated below the transmitter power (P) within
the licensed band(s) of operation, measured in watts, in accordance
with the following:
(1) On all frequencies between 769-775 MHz and 799-805 MHz, by a factor
not less than 76 + 10 log (P) dB in a 6.25 kHz band segment, for base
and fixed stations.
(2) On all frequencies between 769-775 MHz and 799-805 MHz, by a factor
not less than 65 + 10 log (P) dB in a 6.25 kHz band segment, for mobile
and portable stations.
(3) On any frequency between 775-788 MHz, above 805 MHz, and below 758
MHz, by at least 43 + 10 log (P) dB.
(4) Compliance with the provisions of paragraphs (e)(1) and (2) of this
section is based on the use of measurement instrumentation such that
the reading taken with any resolution bandwidth setting should be
adjusted to indicate spectral energy in a 6.25 kHz segment.
(5) Compliance with the provisions of paragraph (e)(3) of this section
is based on the use of measurement instrumentation employing a
resolution bandwidth of 100 kHz or greater. However, in the 100 kHz
bands immediately outside and adjacent to the frequency block, a
resolution bandwidth of 30 kHz may be employed.
(f) For operations in the 758-775 MHz and 788-805 MHz bands, all
emissions including harmonics in the band 1559-1610 MHz shall be
limited to −70 dBW/MHz equivalent isotropically radiated power (EIRP)
for wideband signals, and −80 dBW EIRP for discrete emissions of less
than 700 Hz bandwidth. For the purpose of equipment authorization, a
transmitter shall be tested with an antenna that is representative of
the type that will be used with the equipment in normal operation.
(g) When an emission outside of the authorized bandwidth causes harmful
interference, the Commission may, at its discretion, require greater
attenuation than specified in this section.
[ 70 FR 21666 , Apr. 27, 2005, as amended at 72 FR 48862 , Aug. 24, 2007;
79 FR 600 , Jan. 6, 2014; 79 FR 39340 , July 10, 2014; 79 FR 71326 , Dec.
2, 2014]
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Goto Section: 90.542 | 90.547
Goto Year: 2018 |
2020
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