Signal To Noise Ratio. What is this all about !

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By definition, SNR (Signal-to-Noise Ratio) is a measure in science and technology that represents the ratio of a signal's power to the power of the accompanying background noise. Because this dynamic range can be very wide, SNR is generally expressed in decibels (dB).


SNR Calculation Formulas

For power ratios, the formula is:


Where both powers  (Psignal and Pnoise) must be in the same units, such as watts or milliwatts.



Important Note

On a device's datasheet, unless specifically stated, the listed dB value always refers to a power ratio, not a voltage ratio.

If the ratio is expressed in terms of voltage, the formula is:


Where both voltages (Vsignal and Vnoise) must be in the same units, such as volts or millivolts. This formula uses a factor of 20 because power (P) is proportional to the square of the voltage ( V^2), and 10.log(Vsignal)^2 = 20.log(Vnoise)^2


Illustration of SNR in Photography

The definition of SNR applies to all branches of science and technology, whether electronic, mechanical, video, audio, optical, or others. For example, in the following image, you can see a presentation of several photos with different SNR values. It is clear that as the SNR value decreases, the image becomes blurrier and its quality degrades.


where


I hope this brief note is helpful and serves as a reminder. Keep up the good work, stay positive and optimistic, and don't forget to be happy. TABIK !


(This post is parallel to the status on the FaceBookGroup The Art of Electronics with the same Topic)


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