Radio-frequency sweep

Radio-frequency sweep

Radio frequency sweep or "Frequency sweep" or "RF sweep" refer to scanning a radio frequency band for detecting signals being transmitted there. This is implemented using a radio receiver having a tunable receiving frequency. As the frequency of the receiver is changed to scan (sweep) a desired frequency band, a display indicates the power of the signals received at each frequency.


Methods and tools

A spectrum analyzer is a standard instrument used for RF sweep. It includes an electronically tunable receiver and a display. The display presents measured power (y axis) vs frequency (x axis). The power spectrum display is a two-dimensional display of measured power vs. frequency. The power may be either in linear units, or logarithmic units (dBm). Usually the logarithmic display is more useful, because it presents a larger dynamic range with better detail at each value. An RF sweep relates to a receiver which changes its frequency of operation continuously from a minimum frequency to a maximum (or from maximum to minimum). Usually the sweep is performed at a fixed, controllable rate, for example 5 MHz/sec.

Some systems use frequency hopping, switching from one frequency of operation to another. One method of CDMA uses frequency hopping. Usually frequency hopping is performed in a random or pseudo-random pattern.


Frequency sweeps may be used by regulatory agencies to monitor the radio spectrum, to ensure that users only transmit according to their licenses. The FCC for example controls and monitors the use of the spectrum in U.S.A. In testing of new electronic devices, a frequency sweep may be done to measure the performance of electronic components or systems. For example, RF oscillators are measured for phase noise, harmonics and spurious signals; computers for consumer sale are tested to avoid radio frequency interference with radio systems. Portable sweep equipment may be used to detect some types of covert listening device (bugs).

See also


1. Donald G. Fink, Donald Christiansen – Electronic Engineer's Handbook, Second edition ISBN 0-07-020981-2

2. Ulrich L. Rohde, Jerry C. Whitaker, T.T.N. Bucher – Communications Receivers: Principles and Design, Second edition. ISBN 0-07-053608-2

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Radio jamming — is the (usually deliberate) transmission of radio signals that disrupt communications by decreasing the signal to noise ratio. Unintentional jamming occurs when an operator transmits on a busy frequency without checking that it is in use first,… …   Wikipedia

  • FMCW — Frequency Modulated Continuous wave radar (FM CW) is a radar system where a known stable frequency continuous wave radio energy is modulated by a triangular modulation signal so that it varies gradually and then mixes with the signal reflected… …   Wikipedia

  • Oscilloscope types — This is a subdivision of the Oscilloscope article, discussing the various types and models of oscilloscopes in greater detail. Contents 1 Cathode ray oscilloscope (CRO) 1.1 Dual beam oscilloscope 2 Analog storage oscilloscope …   Wikipedia

  • Oil shale extraction — is an industrial process in which kerogen mdash;a mixture of organic chemical compounds (including hydrocarbons) found in oil shale mdash;is converted into synthetic crude oil through pyrolysis. In pyrolysis, oil shale is heated in the absence of …   Wikipedia

  • Atomic clock — Nuclear clock redirects here. For the clock as a measure for risk of catastrophic destruction, see Doomsday Clock. For a clock updated by radio signals (commonly but inaccurately called an atomic clock ), see Radio clock. For the album by Zion I …   Wikipedia

  • Radar jamming and deception — is the intentional emission of radio frequency signals to interfere with the operation of a radar by saturating its receiver with noise or false information. There are two types of radar jamming: Mechanical and Electronic jamming . Mechanical… …   Wikipedia

  • Signals intelligence — SIGINT redirects here. For the UNIX signal, see SIGINT (POSIX). RAF Menwith Hill, a large site in the United Kingdom, part of ECHELON and the UK USA Security Agreement. Signals intelligence (often contracted to SIGINT) is intelligence gathering… …   Wikipedia

  • Cavity magnetron — Magnetron with section removed (magnet is not shown) …   Wikipedia

  • Phase-locked loop — PLL redirects here. For other uses, see PLL (disambiguation). A phase locked loop or phase lock loop (PLL) is a control system that generates an output signal whose phase is related to the phase of an input reference signal. It is an electronic… …   Wikipedia

  • Technical Surveillance Counter-Measures — TSCM (Technical Surveillance Counter Measures) is the original Unites States military abbreviation denoting the process of bug sweeping or electronic countersurveillance. It is related to ELINT, SIGINT and Electronic countermeasures (ECM).The… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”