# Noise Power Calculations in dB or dBm

• Kartik.Sulakh
In summary, noise power is a measure of the random fluctuations in an electrical signal or system, and is commonly expressed in decibels (dB) or decibels relative to milliwatts (dBm). It is calculated using a logarithmic scale that allows for easy comparison of a wide range of power values. Noise power can affect the performance of a system by decreasing the signal-to-noise ratio and can be minimized through the use of low-noise components, proper shielding and grounding techniques, and signal processing algorithms. It can be used to measure both analog and digital signals, with the reference power level depending on the type of signal being measured. Common sources of noise power include thermal noise, intermodulation distortion, and electromagnetic interference.
Kartik.Sulakh
The ourput Noise Power is given as
No = kTsBG + kTeBG
...= k.(Ts+Te).B.G
But when it is asked in dB or dBm,
How to calculate it something like 10Log10(Value) or 20Log10(Value)

dBm is a unit of power (dB referenced to 1 mW)
dB is a (dimensionless) ratio (value/reference in dB).

Hence, if you want noise power you need to use dBm.
All you need is 10log10 (P/P0) where P is the power and P0 is 1 mW.

## 1. What is noise power and why is it measured in decibels (dB) or decibels relative to milliwatts (dBm)?

Noise power is the measure of the random fluctuations in an electrical signal or system. It is measured in decibels (dB) because it is a logarithmic scale that allows for easier comparison and representation of a wide range of power values. Decibels relative to milliwatts (dBm) is a common unit used in telecommunications and RF engineering to express power levels in relation to a reference value of 1 milliwatt.

## 2. How is noise power calculated in dB or dBm?

Noise power in dB or dBm is calculated using the formula: P(dB/dBm) = 10*log10 (P/P0), where P is the measured power and P0 is the reference power level. For example, if the reference power level is 1 milliwatt, and the measured power is 10 milliwatts, the noise power would be 10 dBm.

## 3. Can noise power calculations in dB or dBm be used for both analog and digital signals?

Yes, noise power calculations in dB or dBm can be used for both analog and digital signals. However, the reference power level may vary depending on the type of signal being measured. For example, in digital systems, the reference power level may be based on the bit rate or signal-to-noise ratio (SNR).

## 4. How does noise power affect the performance of a system?

Noise power can degrade the performance of a system by reducing the signal-to-noise ratio, which is the ratio of the desired signal power to the noise power. Higher noise power can decrease the sensitivity and accuracy of a system, leading to errors and reduced performance.

## 5. What are some common sources of noise power and how can it be minimized?

Some common sources of noise power include thermal noise, intermodulation distortion, and electromagnetic interference. To minimize noise power, engineers can use low-noise components, proper shielding and grounding techniques, and signal processing algorithms to filter out unwanted noise. In addition, minimizing the physical distance between components and using high-quality cables and connectors can also help reduce noise power.

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