Center frequency

Center frequency

In electrical engineering and telecommunications, the center frequency of a filter or channel is a measure of a central frequency between the upper and lower cutoff frequencies. It is usually defined as either the arithmetic mean or the geometric mean of the lower cutoff frequency and the upper cutoff frequency of a band-pass system or a band-stop system.

Typically, the geometric mean is used in systems based on certain transformations of lowpass filter designs, where the frequency response is constructed to be symmetric on a logarithmic frequency scale. [cite book | title = CRC Handbook of Electrical Filters | author = John T. Taylor and Qiuting Huang | publisher = CRC Press | isbn = 0849389518 | year = 1997| url = http://books.google.com/books?id=HtyKSVF6zPsC&pg=PA57&ots=3n1Qvbs5Me&dq=center+frequency+bandpass+%22geometric+mean%22&as_brr=3&sig=FKeDPjh1YZ8AjDUK1WTu9ezr3p8#PPA57,M1] The geometric center frequency corresponds to a mapping of the DC response of the prototype lowpass filter, which is a resonant frequency sometimes equal to the peak frequency of such systems, for example as in a Butterworth filter.

The arithmetic definition is used in more general situations, such as in describing passband telecommunication systems, where filters are not necessarily symmetric but are treated on a linear frequency scale for applications such as frequency-division multiplexing. [cite book | title = Fiber Optics Illustrated Dictionary | author = Julie K. Petersen | isbn = 084931349X | year = 2003 | publisher = CRC Press | url = http://books.google.com/books?id=AcGFlqSqNEUC&pg=PA100&ots=xJ2Rd91Ovh&dq=center+frequency+bandpass+%22arithmetic+mean%22+fdm&sig=cOaKer3Z6218tzEbEnss8Gj7mr4]

ee also

*Band-pass filter

References

External links

* [http://www.sengpielaudio.com/calculator-geommean.htm Calculations and comparisons between the geometric mean and the arithmetic mean]


Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • audio center frequency — centrinis garso dažnis statusas T sritis radioelektronika atitikmenys: angl. audio center frequency vok. mittlere Frequenz des Tonträgers, f; Zentralfrequenz des Tonträgers, f rus. центральная частота звукового сигнала, f pranc. fréquence… …   Radioelektronikos terminų žodynas

  • audio carrier center frequency — centrinis garso nešlio dažnis statusas T sritis radioelektronika atitikmenys: angl. audio carrier center frequency vok. mittlere Frequenz des Tonträgers, f rus. центральная частота канала звукового сопровождения, f pranc. fréquence nominale de… …   Radioelektronikos terminų žodynas

  • Frequency deviation — (Δf) is used in FM radio to describe the maximum instantaneous difference between an FM modulated frequency and the nominal carrier frequency. The term is sometimes mistakenly used as synonymous with frequency drift, which is an unintended offset …   Wikipedia

  • Frequency modulation — See also: Amplitude modulation In telecommunications, frequency modulation (FM) conveys information over a carrier wave by varying its frequency (contrast this with amplitude modulation, in which the amplitude of the carrier is varied while its… …   Wikipedia

  • Center of Excellence for Stability Police Units — Logo CoESPU The Center of Excellence for Stability Police Units is a training center and a doctrinal hub created by the Italian government on the 1st of March 2005, in accordance with the G8 Action Plan “Expanding Global Capability for Peace… …   Wikipedia

  • Radio-frequency identification — (RFID) is a technology that uses radio waves to transfer data from an electronic tag, called RFID tag or label, attached to an object, through a reader for the purpose of identifying and tracking the object. Some RFID tags can be read from… …   Wikipedia

  • Tuned radio frequency receiver — A tuned radio frequency receiver (TRF receiver) is a radio receiver that is usually composed of several tuned radio frequency amplifiers followed by circuits to detect and amplify the audio signal. A 3 stage TRF receiver includes a RF stage, a… …   Wikipedia

  • Cutoff frequency — This article is about signal processing. For other uses, see Cutoff (disambiguation). Magnitude transfer function of a bandpass filter with lower 3 dB cutoff frequency f1 and upper 3dB cutoff frequency f2 …   Wikipedia

  • Carrier frequency — is a term used to designate: * The nominal frequency of a carrier wave * The center frequency of a frequency modulation signal * The frequency of the unmodulated electrical wave at the output of an amplitude modulated (AM), frequency modulated… …   Wikipedia

  • Dual-tone multi-frequency signaling — One of the few production telephone DTMF keypads with all 16 keys, from an Autovon Telephone. The column of red keys produces the A, B, C, and D DTMF events. Dual tone multi frequency signaling (DTMF) is used for telecommunication signaling over… …   Wikipedia

Share the article and excerpts

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