Narrowband signals are signals that occupy a narrow range of frequencies or that have a small

fractional bandwidth Bandwidth is the difference between the upper and lower frequencies in a continuous band of frequencies. It is typically measured in unit of hertz (symbol Hz). It may refer more specifically to two subcategories: ''Passband bandwidth'' is th ...

. In the

audio Audio most commonly refers to sound, as it is transmitted in signal form. It may also refer to: Sound *Audio signal, an electrical representation of sound *Audio frequency, a frequency in the audio spectrum *Digital audio, representation of sound ...

spectrum, ''narrowband sounds'' are sounds that occupy a narrow range of

frequencies Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio ...

. In

telephony Telephony ( ) is the field of technology involving the development, application, and deployment of telecommunications services for the purpose of electronic transmission of voice, fax, or data, between distant parties. The history of telephony is ...

, narrowband is usually considered to cover frequencies 300–3400 Hz, i.e. the

voiceband A voice frequency (VF) or voice band is the range of audio frequencies used for the transmission of speech. Frequency band In telephony, the usable voice frequency band ranges from approximately 300 to 3400 Hz. It is for this reason th ...

. In

radio communications Radio is the technology of communicating using radio waves. Radio waves are electromagnetic waves of frequency between 3 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected t ...

, a narrowband channel is a channel in which the

bandwidth Bandwidth commonly refers to: * Bandwidth (signal processing) or ''analog bandwidth'', ''frequency bandwidth'', or ''radio bandwidth'', a measure of the width of a frequency range * Bandwidth (computing), the rate of data transfer, bit rate or thr ...

of the message does not significantly exceed the channel's

coherence bandwidth Coherence bandwidth is a statistical measurement of the range of frequencies over which the channel can be considered "flat", or in other words the approximate maximum bandwidth or frequency interval over which two frequencies of a signal are like ...

. In the study of wired channels, ''narrowband'' implies that the channel under consideration is sufficiently narrow that its

frequency response In signal processing and electronics, the frequency response of a system is the quantitative measure of the magnitude and Phase (waves), phase of the output as a function of input frequency. The frequency response is widely used in the design and ...

can be considered flat. The message bandwidth will therefore be less than the

of the channel. That is, no channel has perfectly

flat fading In wireless communications, fading is the variation of signal attenuation over variables like time, geographical position, and radio frequency. Fading is often modeled as a random process. In wireless systems, fading may either be due to multi ...

, but the analysis of many aspects of wireless systems is greatly simplified if flat fading can be assumed.

Two-way radio narrowband

Two-Way Radio Narrowbanding refers to a U.S.

Federal Communications Commission The Federal Communications Commission (FCC) is an independent agency of the United States government that regulates communications by radio, television, wire, internet, wi-fi, satellite, and cable across the United States. The FCC maintains j ...

(FCC) Order issued in December 2004 requiring all CFR 47 Part 90 VHF (150–174 MHz) and UHF (421–470 MHz) PLMR (Private Land Mobile Radio) licensees operating legacy wideband (25 kHz bandwidth) voice or data/

SCADA SCADA (an acronym for supervisory control and data acquisition) is a control system architecture comprising computers, networked data communications and graphical user interfaces for high-level supervision of machines and processes. It also cove ...

systems to migrate to narrowband (12.5 kHz bandwidth or equivalent) systems by 1 January 2013.

Call 911References

External links

* * * {{cite web , title=Narrowbanding resource guide , year=2013 , url=http://www.narrowband.us/ , via=narrowband.us Radio

Two-way radio narrowband

See also

Call 911References

External links