Phaser

A phaser is an electronic audio signal processor used to distort a signal by mixing a dry, or unprocessed, signal with copy of itself that has been filtered through an all-pass phase-shift network. As the filtered signal is mixed with the dry signal, the effect is that of a comb filter, notching out and reinforcing frequencies at fixed intervals up the frequency spectrum. When the all-pass filtered signal alone is heard at the output, the effect is commonly referred to as vibrato.

In motion picture or television production, the effect created by a phaser is often used to imply that the sound is synthetically generated (e.g. a computer or robot voice). The technique works because the frequency filtering produces sound we associate with mechanical sources, which only generate specific frequencies, rather than natural sources, which produce a range of frequencies.

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Phasers are a weapon in the fictional series Star Trek.