Prescaler

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A prescaler is an electronic counting circuit used to reduce a high frequency electrical signal to a lower frequency by integer division.

Contents  [hide] 1 Example of use 2 Nomenclature 3 See also 4 References 5 External links

[edit]Example of use

Prescalers are typically used at very high frequency to extend the upper frequency range of frequency counters, 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 comparison frequency. For this reason, it is common to either restrict the integer to a low value, or use a dual-modulus prescaler 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) integers, such as 32 and 33. Common fixed-integer microwave prescalers are available in modulus 2, 4, 8, 5 and 10, and can operate at frequencies in excess of 10 GHz.^[1]

[edit]Nomenclature

A prescaler is essentially a counter-divider, and thus the names may be used somewhat interchangeably.

[edit]See also

• Dual-modulus prescaler
• Phase locked loop
• Frequency counter
• Frequency divider

[edit]References

1. ^ Examples of fixed integer prescalers: http://hittite.com/products/index.html/category/34

[edit]External links

• Fixed-modulus prescalers available from Hittite Microwave
• A Freescale dual-modulus prescaler
• Electronics Manufacturers

Categories: Electronic circuits