Section 90.535 - Modulation and spectrum usage efficiency requirementsTransmitters designed to operate in 769-775 MHz and 799-805 MHz frequency bands must meet the following modulation standards:
(a) All transmitters in the 769-775 MHz and 799-805 MHz frequency bands must use digital modulation. Mobile and portable transmitters may have analog modulation capability only as a secondary mode in addition to its primary digital mode except on the interoperability channels listed in § 90.531(b)(1) . Analog modulation is prohibited on the interoperability channels. Mobile and portable transmitters that only operate on the low power channels designated in § 90.531(b)(3) and (4) are exempt from this digital modulation requirement.(b) Transmitters designed to operate in the narrowband segment using digital modulation must be capable of maintaining a minimum data (non-voice) rate of 4.8 kbps per 6.25 kHz of bandwidth.(c) Transmitters designed to operate in the wideband segment using digital modulation must be capable of maintaining a minimum data (non-voice) rate of 384 kbps per 150 kHz of bandwidth.(d) Transmitters designed to operate on the channels listed in paragraphs (b)(2), (5), (6), and (7) of § 90.531 must be capable of operating in the voice mode at an efficiency of at least one voice path per 12.5 kHz of spectrum bandwidth.63 FR 58651, Nov. 2, 1998, as amended at 65 FR 53645 , Sept. 5, 2000; 65 FR 66655 , Nov. 7, 2000; 67 FR 76701 , Dec. 13, 2002; 70 FR 21673 , Apr. 27, 2005; 72 FR 48861 , Aug. 24, 2007; 79 FR 71326 , Dec. 2, 2014; 81 FR 66833 , Sept. 29, 2016