§ 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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