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How to Calculate SNR

SNR stands for Signal to Noise Ratio. Here, signal represents the desired output of the system while the noise represents the undesired output. This quantity is frequently calculated to assess how well the system works. That is, how high the desired output is with respect to the undesired noise level. The higher the SNR, the better is the system performance. Calculation of SNR requires knowledge of the average values of signal and noise levels.

Things You'll Need

Paper and pen
Calculator

Instructions

- 1
  Divide the average signal power by the average noise power using a calculator and call it SNR. For example; if the signal power is 20.8 and the noise power is 1.4, the formula is given as SNR = 20.8/1.4 = 14.8.
- 2
  Call the base-10 logarithm of the SNR, SNRL. This can be done by entering the value of the SNR calculated earlier in the calculator and pressing "LOG" button. For the example; SNRL = log(SNR) = log(14.8) = 1.17.
- 3
  Multiply the SNRL by 10 to get the SNR level in decibel. Decibel is a unit frequently used in situations where the parameter can assume any value between a very wide range of values. This is generally the case with SNR for most systems and, therefore, is common to represent this parameter in decibels. For the example; SNRdb = 10 X 1.17 = 11.7 decibel.

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