Title 47: Telecommunication
PART 90—PRIVATE LAND MOBILE RADIO SERVICES
Subpart R—Regulations Governing the Licensing and Use of Frequencies in the 764–776 and 794–806 MHz Bands
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§ 90.543 Emission limitations.
Transmitters designed to operate in 764 776 MHz and 794 806 MHz frequency bands must meet the emission limitations in 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------------------------------------------------------------------------ Measurement Maximum ACP Offset from center frequency (kHz) bandwidth (kHz) relative (dBc)------------------------------------------------------------------------6.25 6.25 -4012.5 6.25 -6018.75 6.25 -6025.00 6.25 -6537.50 25.00 -6562.50 25.00 -6587.50 25.00 -65150.00 100.00 -65250.00 100.00 -65350.00 100.00 -65>400 kHz to 12 MHz 30 (s) -7512 MHz to paired receive band 30 (s) -75In the paired receive band 30 (s) -100------------------------------------------------------------------------
12.5 kHz Mobile Transmitter ACP Requirements------------------------------------------------------------------------ Measurement Maximum ACP Offset from center frequency (kHz) bandwidth (kHz) relative (dBc)------------------------------------------------------------------------9.375 6.25 -4015.625 6.25 -6021.875 6.25 -6037.50 25.00 -6062.50 25.00 -6587.50 25.00 -65150.00 100 -65250.00 100 -65350.00 100 -65>400 to 12 MHz 30 (s) -7512 MHz to paired receive band 30 (s) -75In the paired receive band 30 (s) -100------------------------------------------------------------------------
25 kHz Mobile Transmitter ACP Requirements------------------------------------------------------------------------ Measurement Offset from center frequency (kHz) bandwidth Maximum ACP (kHz) relative (dBc)------------------------------------------------------------------------15.625 6.25 -4021.875 6.25 -6037.50 25 -6062.50 25 -6587.50 25 -65150.00 100 -65250.00 100 -65350.00 100 -65>400 kHz to 12 MHz 30 (s) -7512 MHz to paired receive band 30 (s) -75In the paired receive band 30 (s) -100------------------------------------------------------------------------
150 kHz Mobile Transmitter ACP Requirements------------------------------------------------------------------------ Measurement Offset from center frequency (kHz) bandwidth Maximum ACP (kHz) (dBc)------------------------------------------------------------------------100 50 -40200 50 -50300 50 -50400 50 -50600-1000 30 (s) -601000 to receive band 30 (s) -70In the receive band 30 (s) -100------------------------------------------------------------------------
6.25 kHz Base Transmitter ACP Requirements------------------------------------------------------------------------ Measurement Offset from center frequency (kHz) bandwidth Maximum ACP (kHz) (dBc)------------------------------------------------------------------------6.25 6.25 -4012.50 6.25 -6018.75 6.25 -6025.00 6.25 -6537.50 25 -6562.50 25 -6587.50 25 -65150.00 100 -65250.00 100 -65350.00 100 -65>400 to 12 MHz 30 (s) -8012 MHz to paired receive band 30 (s) -80In the paired receive band 30 (s) -100------------------------------------------------------------------------
12.5 kHz Base Transmitter ACP Requirements------------------------------------------------------------------------ Measurement Offset from center frequency (kHz) bandwidth Maximum ACP (kHz) (dBc)------------------------------------------------------------------------9.375 6.25 -4015.625 6.25 -6021.875 6.25 -6037.5 25 -6062.5 25 -6587.5 25 -65150 100 -65250 100 -65350.00 100 -65>400 kHz to 12 MHz 30 (s) -8012 MHz to paired receive band 30 (s) -80In the paired receive band 30 (s) -100------------------------------------------------------------------------
25 kHz Base Transmitter ACP Requirements------------------------------------------------------------------------ Measurement Offset from center frequency (kHz) bandwidth Maximum ACP (kHz) (dBc)------------------------------------------------------------------------15.625 6.25 -4021.875 6.25 -6037.5 25 -6062.5 25 -6587.5 25 -65150 100 -65250 100 -65350 100.00 -65>400 kHz to 12 MHz 30 (s) -8012 MHz to paired receive band 30 (s) -80In the paired receive band 30 (s) -100------------------------------------------------------------------------
150 kHz Base Transmitter ACP Requirements------------------------------------------------------------------------ Measurement Offset from center bandwidth Maximum ACP (dBc) frequency (kHz) (kHz)------------------------------------------------------------------------100 50 -40200 50 -50300 50 -55400 50 -60600-1000 30 (s) -651000 to receive band 30 (s) -75 (continues at 6dB/oct)In the receive band 30 (s) -100------------------------------------------------------------------------
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(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; for a 150 kHz transmitter, set the measurement bandwidth to 150 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 764 to 776 MHz and 794 to 806 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.
(f) 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]
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