Goto Section: 90.542 | 90.547 | Table of Contents

FCC 90.543
Revised as of October 20, 2020
Goto Year:2020 | 2022
  §  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]

   


Goto Section: 90.542 | 90.547

Goto Year: 2020 | 2022
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