---
kind: "section"
citation: "47 C.F.R. § 90.535"
title: "47"
number: "90.535"
heading: "Modulation and spectrum usage efficiency requirements."
url: "https://uscodex.org/cfr/47/90.535"
---

# §90.535. Modulation and spectrum usage efficiency requirements.


Transmitters 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)](/cfr/47/90.531.md?p=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)](/cfr/47/90.531.md?p=b-3) and [(4)](/cfr/47/90.531.md?p=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) Transmitters designed to operate on the channels listed in paragraphs [(b)(2)](/cfr/47/90.531.md?p=b-2), [(5)](/cfr/47/90.531.md?p=b-5), [(6)](/cfr/47/90.531.md?p=b-6), and [(7)](/cfr/47/90.531.md?p=b-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.

## Notes

### Amendments

[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]

### Source

Source: 63 FR 58651, Nov. 2, 1998, unless otherwise noted.

### Authority

Authority: 47 U.S.C. 154(i), 161, 303(g), 303(r), 332(c)(7), 1401-1473

### Source

Source: 43 FR 54791, Nov. 22, 1978, unless otherwise noted.

### Amendments

[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]