This is machine translation

Translated by Microsoft
Mouseover text to see original. Click the button below to return to the English verison of the page.

Note: This page has been translated by MathWorks. Please click here
To view all translated materals including this page, select Japan from the country navigator on the bottom of this page.


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 degrees kelvin.

Input Arguments


The noise bandwidth of the receiver in hertz. For a superheterodyne receiver, the noise bandwidth is approximately equal to the bandwidth of the intermediate frequency stages [1].


Noise figure. 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 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 one.


Reference temperature in degrees kelvin. The temperature of the receiver. Typical values range from 290–300 degrees kelvin.

Output Arguments


Noise power in watts. The internal noise power contribution of the receiver to the signal-to-noise ratio.


collapse all

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 =



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

Extended Capabilities

Introduced in R2011a

Was this topic helpful?