# Signal-to-noise ratio demonstrator

To launch labAlive simulation applications you need a Java Runtime Environment supporting Java Web Start on your system. Here you can get more information about installing the right Java version.

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.