A unit of frequency in the International System of Units (SI), equal to one million cycles per second. It is most commonly used to measure the transmission speeds of electronic devices, the frequency of radio signals, and the clock speeds of microprocessors.
Key Specifications
- Symbol: MHz
- Base Unit: 1 MHz = 1,000,000 Hz (Hertz)
- Dimensions: Time to the -1 power (inverse time)
- Relationship: 1,000 kHz < 1 MHz < 0.001 GHz
Common Applications
- Computing: Historically used to measure the clock speed of CPUs. While modern processors have moved into the gigahertz (GHz) range, MHz is still the standard for measuring RAM (Random Access Memory) speeds and bus frequencies.
- Telecommunications: Used to define bands within the radio spectrum. For example, FM radio broadcasts typically operate between 88 MHz and 108 MHz.
- Physics: Used in Magnetic Resonance Imaging (MRI) to describe the precession frequency of atomic nuclei in a magnetic field.
Contextual Comparison
In the context of data transfer, a higher MHz rating generally indicates a higher bandwidth—the capacity to carry data—but not necessarily the absolute speed, as other factors like latency and architecture play a role. In a 100 MHz system, the time period (T) for a single cycle is:
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Note: Because mega denotes 10 to the sixth power, 1 MHz represents exactly 1,000,000 oscillations every second.