Megahertz

Megahertz in radio

When used in the context of radio, MHz refers to the number of oscillations of electromagnetic radiation per second.
Several parts of the radio spectrum fall into the MHz range:

• LF (Low Frequency) 0.03 - 0.3 MHz
• MF (Medium Frequency) 0.3-3 MHz
• HF (High Frequency) 3-30 MHz
• VHF (Very High Frequency) 30 - 300 MHz
• UHF (Ultra High Frequency) 300 - 1000 MHz

• L-Band 1-2 GHz (1000 MHz = 1 gigahertz GHz)
• S-Band 2-4 GHz
• C-Band 4-8 GHz
• X-Band 8-12 GHz
• Ku-Band 12-18 GHz
• K-Band 18-27 GHz
• Ka Band 27-40 GHz
• V-Band 40-75 GHz
• W- Band 75-110 GHz

Megahertz in computing

Most CPUss made between 1974 and 2000 were labelled in terms of megahertz (though modern computers have processor speeds in the gigahertz (10⁹ hertz) range). The number of megahertz refers to the frequency of the CPU's master clock signal ("clock speed").

Various computer busses, such as memory busses connecting the CPU and system RAM, also transfers data using clock signals operating at frequencies in the megahertz range. The operating frequency of computer busses is sometimes adverticed by computer sellers, though not as often as the CPU frequency.

It is often assumed that if two CPUs have different "clock speeds", the one with the higher clock speed will perform better than the other. However, while clock speed is an important factor in overall performance, many other factors influence the performance of computers, and a better comparison is archived by using benchmarks.

For example, a RISC processor, which has very simple instructions that can be accomplished quickly, may run at a higher clock rate (at higher MHz) than a CISC processor with complex instructions. But because the CISC processor accomplishes more during each clock, it may be faster for any real-world application.

See also