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Frequency is the number times something occurs in a specific amount of time. In computing, frequency is used to measure processing speed, such as the clock speed of a CPU. For example, a 3.2 GHz processor has a frequency of 3.2 gigahertz, or 3,200,000,000 hertz. This means the processor performs 3,200,000,000 cycles each second. Since most instructions require multiple cycles, the number of instructions per second is typically less than the number of clock cycles. Therefore, MIPS, which measures instructions per second, is sometimes used to measure raw computing performance.

Frequency is also used to measure oscillation rates of waves within the electromagnetic spectrum. Some examples include radio waves, microwaves, visible light, and ultraviolet rays. FM radio broadcasts in the range of 87.5 to 108 megahertz. When you tune to 93.7, for example, you are instructing your radio to only receive signals that have an oscillation frequency of 93,700,000 hertz. Wi-Fi signals are broadcast at either 2.4 GHz or 5 GHz, both of which are much higher than the FM radio frequency band. The higher frequency prevents wireless interference and provides a stronger, more reliable signal over shorter distances.

Important: In mathematics, frequency is often abbreviated as "ƒ". It is inversely related to the period of a wave cycle, which is calculated as 1 / ƒ.

Published: August 29, 2013

Definition from the PC Glossary