# Documentation

### This is machine translation

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

# noisepow

## 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

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 = 5.2144e-17 ```

## References

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