quartz/content/signal_processing/basic_knowledge/concept/what_is_dB.md

title	tags	date
What is dB	signal-processing basic	2024-02-28

dB is short for decibel, which is a unit that indicates ratio or gain. It is often used to measure sound intensity, signal strength, attenuation and other quantities.

For example, if a sound has a power of 10 W and another sound has a power of 1 W, then the difference in decibels is 10 dB = 10 log (10/1) = 10 log 10 = 10.

Signal Noise Ratio is also measured by dB

Signal Noise Ratio

{SNR}_{power}=\frac{\text{Average Signal Power}}{\text{Average Noise Power}}

{SNR}_{voltage}=\frac{\text{RMS Signal Voltage}}{\text{RMS Noise Voltage}}

{SNR}_{power}={{SNR}_{voltage}}^2

{SNR}_{dB}=10\log_{10}{{SNR}_{power}}=20\log_{10}{{SNR}_{voltage}}