megahertz

Megahertz (MHz) is a unit of frequency in the International System of Units (SI). One megahertz equals one million hertz, with one hertz defined as one cycle per second. The term is used to measure periodic phenomena such as electromagnetic waves and electronic signal oscillations. In vacuum, frequency f relates to wavelength λ by λ = c / f, where c is the speed of light.

In radio technology, MHz ranges designate transmission and reception bands. The very high frequency (VHF) band spans roughly 30 to 300 MHz and includes FM radio broadcasts (about 88 to 108 MHz), television channels, and various two-way radios. In computing and electronics, MHz historically described processor clock speeds and system buses; modern CPUs are typically measured in gigahertz, but devices such as microcontrollers and some digital signal processing components still operate in the MHz range.

Relatives of megahertz include kilohertz (kHz) = 10^3 Hz and gigahertz (GHz) = 10^9 Hz. Therefore, 1 MHz equals 0.001 GHz. The symbol MHz is used internationally, and the unit is named after Heinrich Hertz for his foundational work on electromagnetic waves.

Common caveats include distinguishing frequency from data rate. MHz measures cycles per second, not the amount of data that can be transmitted. A wireless link’s data throughput depends on bandwidth, modulation, and other factors in addition to the carrier frequency.

Examples: FM radio typically operates around 88–108 MHz, while other communications systems may use bands within the broader 30–300 MHz VHF range.