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What is radio frequency power spectral density (PSD)?

Last Updated on：2024-12-11 07:42:26

Radio Frequency Power Spectral Density (PSD) is a parameter that measures the power distribution of a radio signal in the frequency domain. It describes the distribution of signal power over a frequency range, usually expressed in power units (such as watts/dBm) divided by frequency units (such as hertz), i.e., watts/hertz (W/Hz) or dBm/MHz. PSD is an important indicator because it can show the amount of energy used by a radio transmitter within a specific frequency bandwidth. In wireless communication system design and spectrum management, PSD is used to ensure that radio transmissions do not exceed the specified power limits, and it also helps to assess and prevent interference between different wireless systems. For example, the limit for 2.4G Wi-Fi products in the EU and China is PSD<10dBm/MHz. Within a given bandwidth, if a radio transmitter's power is too high, its PSD value will also be relatively high, which may lead to interference with adjacent channels. Therefore, regulatory agencies typically set upper limits on PSD for specific radio services to maintain the health and order of the electromagnetic environment.