# Effective Noise Power Spectral Density

• Kartik.Sulakh
In summary, to calculate the effective noise power spectral density when a noise factor of 3 is given, you would use the formula N = k.Te.B, where B is the bandwidth. One assumption that needs to be made is the bandwidth, as a wider bandwidth will result in a higher noise power. The effective noise power can be significantly different depending on the bandwidth used, with a 30 dB difference between a 1 Hz and 1000 Hz bandwidth.
Kartik.Sulakh
How to calculate the effective noise power spectral density,
when a noise factor of 3 if given and if said to make any assumptions.

We know Effective Noise Temperature N = k.Te.B
I'm assuming it as Te = 290 K x (10 NF/10 - 1) and what about 'B'?

A noise factor of 3 means that the effective noise power, referred to the input, is 3 times that of the actual input noise power. I think you've got to make a lot of assumptions to make any conclusions other than that.

Kartik.Sulakh said:
We know Effective Noise Temperature N = k.Te.B
I'm assuming it as Te = 290 K x (10 NF/10 - 1) and what about 'B'?

"B" is bandwidth. The wider your bandwidth the more noise you'll have. For a 1 Hz bandwidth the effective noise power is -174 dBm. For a 1 kHz bandwidth it is -144 dBm, a 30 dB difference both between 1 Hz and 1000 Hz and between -174 and -144 dBm.

## What is Effective Noise Power Spectral Density?

Effective Noise Power Spectral Density (ENPSD) is a measure of the noise power that is present in a signal. It is calculated by taking the square of the noise voltage and dividing it by the bandwidth of the signal.

## Why is ENPSD important?

ENPSD is important because it helps to understand the amount of noise present in a signal. It is often used in signal processing and communication systems to evaluate the performance of a system and to determine the required level of signal-to-noise ratio for reliable signal transmission.

## How is ENPSD different from regular noise power spectral density?

ENPSD takes into account the bandwidth of the signal, while regular noise power spectral density does not. This means that ENPSD gives a more accurate representation of the noise power in a signal, as it considers the frequency range of the signal.

## What factors affect ENPSD?

The main factors that affect ENPSD are the noise sources in a system, such as thermal noise, shot noise, and flicker noise. The bandwidth of the signal also plays a significant role, as a wider bandwidth will result in a higher ENPSD.

## How is ENPSD measured?

ENPSD is typically measured using a spectrum analyzer, which measures the power spectral density of a signal. The ENPSD can then be calculated by squaring the measured noise voltage and dividing it by the signal's bandwidth. Alternatively, it can also be calculated using mathematical formulas based on the noise sources in the system.

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