47 C.F.R. § 24.131 Authorized bandwidth.
Title 47 - Telecommunication
The authorized bandwidth of narrowband PCS channels will be 10 kHz for 12.5 kHz channels and 45 kHz for 50 kHz channels. For aggregated adjacent channels, a maximum authorized bandwidth of 5 kHz less than the total aggregated channel width is permitted.
Title 47: Telecommunication
PART 24—PERSONAL COMMUNICATIONS SERVICES
Subpart D—Narrowband PCS
§ 24.131 Authorized bandwidth.