A prescaler is an electronic counting circuit

Counter

In digital logic and computing, a counter is a device which stores the number of times a particular event or process has occurred, often in relationship to a clock signal.- Electronic counters :...

 used to reduce a high frequency

Frequency

Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency.The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency...

 electrical signal to a lower frequency by integer division.

Example of use

Prescalers are typically used at very high frequency to extend the upper frequency range of frequency counter

Frequency counter

A frequency counter is an electronic instrument, or component of one, that is used for measuring frequency. Frequency is defined as the number of events of a particular sort occurring in a set period of time. Frequency counters usually measure the number of oscillations or pulses per second in a...

s, phase locked loop (PLL) synthesizers, and other counting circuits. When used in conjunction with a PLL, a prescaler introduces a normally undesired change in the relationship between the frequency step size and phase detector

Phase detector

A phase detector or phase comparator is a frequency mixer, analog multiplier or logic circuit that generates a voltage signal which represents the difference in phase between two signal inputs...

 comparison frequency. For this reason, it is common to either restrict the integer to a low value, or use a dual-modulus prescaler

Dual-modulus prescaler

A dual modulus prescaler is an electronic circuit used in high-frequency synthesizer designs to overcome the problem of generating narrowly-spaced frequencies that are nevertheless too high to be passed directly through the feedback loop of the system. The modulus of a prescaler is its frequency...

 in this application. A dual-modulus prescaler is one that has the ability to selectively divide the input frequency by one of two (normally consecutive) integer

Integer

The integers are formed by the natural numbers together with the negatives of the non-zero natural numbers .They are known as Positive and Negative Integers respectively...

s, such as 32 and 33. Common fixed-integer microwave

Microwave

Microwaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...

 prescalers are available in modulus 2, 4, 8, 5 and 10, and can operate at frequencies in excess of 10 GHz

GHZ

GHZ or GHz may refer to:# Gigahertz .# Greenberger-Horne-Zeilinger state — a quantum entanglement of three particles.# Galactic Habitable Zone — the region of a galaxy that is favorable to the formation of life....

.

Nomenclature

A prescaler is essentially a counter

Counter

In digital logic and computing, a counter is a device which stores the number of times a particular event or process has occurred, often in relationship to a clock signal.- Electronic counters :...

-divider, and thus the names may be used somewhat interchangeably.

See also

• Dual-modulus prescaler
  Dual-modulus prescaler
  A dual modulus prescaler is an electronic circuit used in high-frequency synthesizer designs to overcome the problem of generating narrowly-spaced frequencies that are nevertheless too high to be passed directly through the feedback loop of the system. The modulus of a prescaler is its frequency...
  
  
• Phase locked loop
• Frequency counter
  Frequency counter
  A frequency counter is an electronic instrument, or component of one, that is used for measuring frequency. Frequency is defined as the number of events of a particular sort occurring in a set period of time. Frequency counters usually measure the number of oscillations or pulses per second in a...
  
  
• Frequency divider