# Signal-to-noise ratio demonstrator

This demonstration shows various signals interfered by noise. Evaluate the signal quality!

• The more the interfered signal (yellow) differs from the original signal (green) the less is the signal quality.
• It's the relative difference not the absolute that matters.

Thus, the signal quality is measured as the ratio of signal power to noise power: Signal-to-noise ratio (SNR).

$SNR= S N = signal power noise power MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBamXvP5wqonvsaeHbd9wDYLwzYbqe e0evGueE0jxyaibaieYlf9irVeeu0dXdh9vqqj=hEeeu0xXdbba9fr Fj0=OqFfea0dXdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXdbPYx e9vr0=vr0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaiaado facaWGobGaamOuaiabg2da9maalaaabaGaam4uaaqaaiaad6eaaaGa eyypa0ZaaSaaaeaacaWGZbGaamyAaiaadEgacaWGUbGaamyyaiaadY gacaaMc8UaamiCaiaad+gacaWG3bGaamyzaiaadkhaaeaacaWGUbGa am4BaiaadMgacaWGZbGaamyzaiaaykW7caWGWbGaam4BaiaadEhaca WGLbGaamOCaaaaaaa@5468@$

The Signal-to-noise ratio is usually measured in decibels (dB).

$SN R dB =10lg S N MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBamXvP5wqonvsaeHbd9wDYLwzYbqe e0evGueE0jxyaibaieYlf9irVeeu0dXdh9vqqj=hEeeu0xXdbba9fr Fj0=OqFfea0dXdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXdbPYx e9vr0=vr0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaiaado facaWGobGaamOuamaaBaaaleaacaWGKbGaamOqaaqabaGccqGH9aqp caaIXaGaaGimaiGacYgacaGGNbWaaSaaaeaacaWGtbaabaGaamOtaa aaaaa@4195@$

Launch the app and try out how different signals will be interfered by noise depending on the S/N-ratio.

SNR Sine wave Audio signal
20 dB
10 dB
6 dB
3 dB
0 dB
Sine wave and audio signals with SNR = 20 dB, 10dB, 6 dB, 3 dB and 0 dB. Noise bandwidth is 1000 Hz.