a type of comb filter, so called because its frequency response has several dips and peaks, like the teeth of a comb
Effect which combines a signal with a phase shifted version of itself to produce creative filtering effects. Most phasers are controlled by means of an LFO.
Also called a "phase shifter," this is an electronic device creating an effect similar to flanging, but not as pronounced. Based on phase shift ( frequency dependent), rather than true signal delay ( frequency independent), the phaser is much easier and cheaper to construct. Using a relatively simple narrow notch filter (all-pass filters also were used) and sweeping it up and down through some frequency range, then summing this output with the original input, creates the desired effect. Narrow notch filters are characterized by having sudden and rather extreme phase shifts just before and just after the deep notch. This generates the needed phase shifts for the ever-changing magnitude cancellations.
A phaser is an audio signal processing technique used to filter a signal by attenuating a series of notches in the frequency spectrum. The position of the notches typically varies over time (modulation), and phasers usually include a low frequency oscillator for this purpose.