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Receiver noise power



NPOWER = noisepow(NBW,NF,REFTEMP) returns the noise power, NPOWER, in watts for a receiver. This receiver has a noise bandwidth NBW in hertz, noise figure NF in decibels, and reference temperature REFTEMP in kelvins.


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Calculate the noise power of a receiver having a noise bandwidth of 10 kHz, a noise figure of 1 dB, and a reference temperature of 300 K.

npower = noisepow(10e3,1,300)
npower = 5.2144e-17

Input Arguments

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Noise bandwidth of the receiver in hertz, specified as a positive scalar. For a superheterodyne receiver, the noise bandwidth is approximately equal to the bandwidth of the intermediate frequency stages [1].

Data Types: double

Noise figure in decibels, specified as a nonnegative scalar. The noise figure is a dimensionless quantity that indicates how much a receiver deviates from an ideal receiver in terms of internal noise. An ideal receiver only produces the expected thermal noise power for a given noise bandwidth and temperature. A noise figure of 1 (0 dB) indicates that the noise power of a receiver equals the noise power of an ideal receiver. Because an actual receiver cannot exhibit a noise power value less than an ideal receiver, the noise figure is always greater than or equal to 1 (0 dB).

Data Types: double

Reference temperature in kelvins, specified as a nonnegative scalar. This argument specifies the temperature of the receiver. Typical values range from 290 to 300 kelvins.

Data Types: double

Output Arguments

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Noise power in watts, returned as a nonnegative scalar. The internal noise power contribution of the receiver to the signal-to-noise ratio.


[1] Skolnik, M. Introduction to Radar Systems. New York: McGraw-Hill, 1980.

Extended Capabilities

Version History

Introduced in R2011a