---
kind: "section"
citation: "47 C.F.R. § 2.201"
title: "47"
number: "2.201"
heading: "Emission, modulation, and transmission characteristics."
url: "https://uscodex.org/cfr/47/2.201"
---

# §2.201. Emission, modulation, and transmission characteristics.


The following system of designating emission, modulation, and transmission characteristics shall be employed.

- (a) **Emissions are designated according to their classification and their necessary bandwidth.**
- (b) **Three symbols are used to describe the basic characteristics of emissions.** Emissions are classified and symbolized according to the following characteristics:
  - (1) **First symbol—** type of modulation of the main carrier;
  - (2) **Second symbol—** nature of signal(s) modulating the main carrier;
  - (3) **Third symbol—** type of information to be transmitted.
- (c) **First Symbol—** types of modulation of the main carrier:
- (d) **Second Symbol—** nature of signal(s) modulating the main carrier:
- (e) **Third Symbol—** type of information to be transmitted: 2
- (f) **Type <I>B</I> emission—** As an exception to the above principles, damped waves are symbolized in the Commission's rules and regulations as type B emission. The use of type B emissions is forbidden.
- (g) Whenever the full designation of an emission is necessary, the symbol for that emission, as given above, shall be preceded by the necessary bandwidth of the emission as indicated in [§ 2.202(b)(1)](/cfr/47/2.202.md?p=b-1).

## Notes

### Amendments

[49 FR 48697, Dec. 14, 1984, as amended at 75 FR 63030, Oct. 13, 2010]

### Authority

Authority: 47 U.S.C. 154, 302a, 303, and 336, unless otherwise noted.

### Source

Source: 28 FR 12465, Nov. 22, 1963, unless otherwise noted.

### Amendments

[49 FR 48697, Dec. 14, 1984, as amended at 75 FR 63030, Oct. 13, 2010]