Frequency divider

A frequency divider, also called a clock divider or scaler or prescaler, is a circuit that takes an input signal of a frequency, , and generates an output signal of a frequency:

where is an integer. Phase-locked loop frequency synthesizers make use of frequency dividers to generate a frequency that is a multiple of a reference frequency. Frequency dividers can be implemented for both analog and digital applications.

Analog dividers

Analog frequency dividers are less common and used only at very high frequencies. Digital dividers implemented in modern IC technologies can work up to tens of GHz.

Regenerative frequency divider

A regenerative frequency divider, also known as a Miller frequency divider, mixes the input signal with the feedback signal from the mixer.

The feedback signal is . This produces sum and difference frequencies , at the output of the mixer. A low pass filter removes the higher frequency and the frequency is amplified and fed back into mixer.

Injection-locked frequency divider