Voltage-controlled filter

Voltage-controlled filter

A voltage-controlled filter (VCF) is an electronic filter whose operating characteristics can be controlled by means of a control voltage applied to one or more inputs. [citebook|title=Analog Days C: the invention and impact of the Moog synthesizer|author= Trevor J. Pinch, Frank Trocco |year=2002|publisher=Harvard University | pages=357|id=ISBN 0674016173|url=http://books.google.com/books?id=3hjvWzkMK-sC&pg=PT281&lpg=PT281&ots=M0RcEbnxce&dq=%22Voltage-controlled+filter%22&as_brr=3&ie=ISO-8859-1&output=html&sig=khYReYuJihOoSP05yerLt21ckYk]

A VCF allows its cutoff frequency and Q factor to be continuously varied; it usually gives a lowpass response, but may also be switchable to allow highpass, bandpass or even notch responses. The filter may offer a switchable "slope" which determines how quickly signals outside the pass band become attenuated, usually 12dB/octave (a '2 pole' filter) or 24dB/octave (a '4 pole' filter).

In analog synthesizers, which are commonly used to make electronic music, VCFs are commonly positioned after the oscillator(s). The oscillator generates an audio waveform, which (except for noise waveforms) includes a fundamental pitch and a series of harmonic overtones. By varying the cutoff frequency (the maximum frequency passed by the filter), the synth operator can add or remove some of the overtones to create more interesting and textured sounds.

In much electronic music, "filter sweeps" have become a common effect. These sweeps are created by varying the cutoff frequency of the VCF (sometimes very slowly) to reveal or conceal the oscillator's overtones.

A VCF is an example of an active non-linear filter: however, if its control voltage is kept constant, it will behave as a linear filter.

See also

* Electronic filter
* Non-linear filter
* Self oscillation
* Subtractive synthesis
* Voltage-controlled amplifier
* Voltage-controlled oscillator

References

External links

* [http://www.musicfromouterspace.com/analogsynth/AAA_VCFilterIndex.html Schematics and PCBs for building your own VCF]


Wikimedia Foundation. 2010.

Игры ⚽ Нужен реферат?

Look at other dictionaries:

  • Voltage Controlled Filter — Ein spannungsgesteuertes Filter (engl. voltage controlled filter, kurz VCF), ist ein elektrisches Filter mit dem sich die Eckfrequenz (engl. cut off) mittels einer Steuerspannung variieren lässt. Die Eckfrequenz ist jene Frequenz, an welcher das… …   Deutsch Wikipedia

  • Filter — Fil|ter [ fɪltɐ], der, fachspr. auch: das; s, : a) durchlässiges Material, das zum Filtern von flüssigen oder gasförmigen Stoffen verwendet wird: in dieser Kläranlage dient Kies als Filter. Syn.: ↑ Sieb. Zus.: Luftfilter, Staubfilter. b)… …   Universal-Lexikon

  • Voltage divider — In electronics, a voltage divider (also known as a potential divider) is a simple linear circuit that produces an output voltage ( V out) that is a fraction of its input voltage ( V in). Voltage division refers to the partitioning of a voltage… …   Wikipedia

  • French Filter House — Dieser Artikel oder Abschnitt ist nicht hinreichend mit Belegen (Literatur, Webseiten oder Einzelnachweisen) versehen. Die fraglichen Angaben werden daher möglicherweise demnächst gelöscht. Hilf Wikipedia, indem du die Angaben recherchierst und… …   Deutsch Wikipedia

  • Spannungsgesteuertes Filter — Ein spannungsgesteuerter Filter (engl. voltage controlled filter, kurz VCF), ist ein elektrischer Filter mit dem sich die Eckfrequenz (engl. cut off) mittels einer Steuerspannung variieren lässt. Die Eckfrequenz ist jene Frequenz, an welcher das… …   Deutsch Wikipedia

  • Electronic filter — Electronic filters are electronic circuits which perform signal processing functions, specifically intended to remove unwanted signal components and/or enhance wanted ones. Electronic filters can be:*passive or active *analog or digital *discrete …   Wikipedia

  • Control Voltage — Die Control Voltage (deutsch Kontrollspannung, jedoch als terminus technicus im Deutschen Steuerspannung) dient den analogen Synthesizern (vor allen den Modularsynthesizern) dazu, über eine Steuerspannung die verschiedenen Parameter der Klangs zu …   Deutsch Wikipedia

  • Voltage doubler — A voltage doubler is an electronic circuit which charges capacitors from the input voltage and switches these charges in such a way that, in the ideal case, exactly twice the voltage is produced at the output as at its input. The simplest of… …   Wikipedia

  • All-pass filter — An all pass filter is an electronic filter that passes all frequencies equally, but changes the phase relationship between various frequencies. It does this by varying its propagation delay with frequency. Generally, the filter is described by… …   Wikipedia

  • Sallen–Key filter — A Sallen–Key filter is a type of active filter, particularly valued for its simplicity. The circuit produces a 2 pole (12 dB/octave) lowpass or highpass response using two resistors, two capacitors and (usually) a unity gain buffer amplifier.… …   Wikipedia

Share the article and excerpts

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