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noisepow

Receiver noise power

Syntax

NPOWER = noisepow(NBW,NF,REFTEMP)

Description

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

NBW

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].

NF

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.

REFTEMP

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

Output Arguments

NPOWER

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

Examples

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

npower = noisepow(10e3,1,300);

References

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

See Also

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