Sec.  90.535   Modulation and spectrum usage efficiency requirements.

   Transmitters designed to operate in 764–776 MHz and 794–806 MHz frequency
   bands must meet the following modulation standards:

   (a) All transmitters in the 764–776 MHz and 794–806 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. Mobile and portable transmitters that only operate on the low
   power channels designated in  Sec.  Sec. 90.531(b)(3), 90.531(b)(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) The following provisions apply to licensees operating in the channels
   designated in  Sec.  Sec. 90.531(b)(5) or 90.531(b)(6).

   (1) With the exception of licensees designated in paragraph (d)(2) of this
   section, after December 31, 2014, licensees may only operate in voice mode
   in these channels at a voice efficiency of at least one voice path per 6.25
   kHz of spectrum bandwidth.

   (2) Licensees authorized to operate systems in the voice mode on these
   channels from applications filed on or before December 31, 2014, may
   continue operating in voice mode on these channels (including modification
   applications of such licenses granted after December 31, 2014, for expansion
   or maintenance of such systems) at a voice efficiency of at least one voice
   path per 12.5 kHz of spectrum bandwidth until December 31, 2016.

   (3) The licensees designated in paragraph (d)(2) of this section must, no
   later than January 31, 2017, file a declaration through the Universal
   Licensing System that they are operating these channels at a voice
   efficiency of at least one voice path per 6.25 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]