A frequency multiplier is an electronic circuit that creates a (typically integer) harmonic of its input frequency – for example it could be used to double a 200 Hz input to 400 Hz at the output. Frequency multipliers use a nonlinear circuit to severely distort the input signal, before applying a band-pass filter to only provide the desired multiple of the input frequency. A frequency divider does the inverse of a frequency multiplier, in that it divides an input frequency to a lower rate.

Frequency multipliers and dividers are used in both digital and analog applications.

## Uses for frequency multipliers

Frequency multipliers are often seen as a more economical way to create high-frequency signals from low-frequency inputs, which are easier to generate. Common applications include PLL frequency synthesisers, signal generators and communications circuits.

## Uses for frequency dividers

Frequency dividers can be used for applications including satellite communications, fibre optics and point-to-multipoint radios, as these require very high frequencies to operate effectively.