# Signal To Noise Ratio

• posted

Is the better signal to noise ratio the larger or smaller? For instance - 80 or 100dB?

• posted

The larger the number the better.

100dB means the signal level is 100000 times larger than the noise. 80dB means the signal level is 10000 times larger than the noise.

Here is some info:

Dave :)

• posted

Err Dave, this some New World maths?

Last time I checked, a 60dB power ratio was 1,000,000 : 1

70dB = 10,000,000 : 1 80dB = 100,000,000 : 1 90dB = 1,000,000,000 : 1 100dB = 10,000,000,000 : 1 0dB = 1 : 1 3dB = 2 : 1 10dB = 10 : 1 20dB = 100 : 1 30dB = 1,000 : 1

It's a logarithmic ratio. Get the picture?

The formula is dB = 10 log(base10) Ps/Pn; where Ps and Pn represent the signal and noise power levels respectively.

When comparing voltages (where the impedances are the same) the formula of dB = 20 log(base10) Vs/Vn ; where Vs and Vn represent the voltages of the signal and noise levels respectively.

Cheers, Alan

• posted

It's the ratio of signal to noise, in other words signal divided by noise.

Large numbers are generalkly preferable.

Bye. Jasen

• posted

My figures are correct for a voltage ratio. By saying "signal level" I was implying the voltage levels, sorry, thought that was obvious. I didn't want to go into impedances.

The link I posted shows both fomula. Hopefully the OP wasn't too confused. For a beginner, voltage levels would be easier to understand than power levels.

Dave :)

• posted

-100dB is 20dB quieter than -80dB. In context most ROOMS have a background noise level of around 60dB below averagely loud music.

geoff

• posted

power

10dB = x10

voltage

20dB = x10

simple

: > > The larger the number the better. : > >

: > > 100dB means the signal level is 100000 times larger than the noise. : > > 80dB means the signal level is 10000 times larger than the noise. : > >

: > > Here is some info: : > >

: > >

: > > Dave :) : > >

: >

: > Err Dave, this some New World maths? : >

: > Last time I checked, a 60dB power ratio was 1,000,000 : 1 : > 70dB = 10,000,000 : 1 : > 80dB = 100,000,000 : 1 : > 90dB = 1,000,000,000 : 1 : > 100dB = 10,000,000,000 : 1 : > 0dB = 1 : 1 : > 3dB = 2 : 1 : > 10dB = 10 : 1 : > 20dB = 100 : 1 : > 30dB = 1,000 : 1 : >

: > It's a logarithmic ratio. Get the picture? : >

: > The formula is dB = 10 log(base10) Ps/Pn; where Ps and Pn represent the : > signal and noise power levels respectively. : >

: > When comparing voltages (where the impedances are the same) the formula of : > dB = 20 log(base10) Vs/Vn ; where Vs and Vn represent the voltages of the : > signal and noise levels respectively. : : My figures are correct for a voltage ratio. : By saying "signal level" I was implying the voltage levels, sorry, : thought that was obvious. I didn't want to go into impedances. : : The link I posted shows both fomula. Hopefully the OP wasn't too : confused. For a beginner, voltage levels would be easier to understand : than power levels. : : Dave :) :

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.