Hi,
This is not related to ADSP but it os a DSP question
If I have to a noise of 3 DB what is the meaning of that?
IS it noise power equal to 3DB or SNR equal to 3 DB?
can anyone help me out as I need to test my module with adding noise.
any links or suggestion for this.
thanks in advance.
Regards
Ravi chandran
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question on noise in DSP
Started by ●June 24, 2006
Reply by ●June 24, 20062006-06-24
On Sun, 4 Jun 2006, Ravichandran wrote:
>
> Hi,
>
> This is not related to ADSP but it os a DSP question
> If I have to a noise of 3 DB what is the meaning of that?
> IS it noise power equal to 3DB or SNR equal to 3 DB?
>
> can anyone help me out as I need to test my module with adding noise.
> any links or suggestion for this.
It is definitly not clear. You can boil your question down to "relative"
versus "absolute" difference. decibell is made unitless by taking the
ratio of power levels. You can have a fixed reference like 1 milliwatt
in both cases, and have a 3dB absolute noise level or SNR. In the first
case you can define the noise to be a 1/f distribution or "white" between
certain bounds or even gaussian distribution. 3 dB can be measured
relative to that definition for an absolute measure of noise. Or you can
have a 1 kHz tone at 1 milliwatt and measure your noise level relative to
that and it's one possible SNR measure.
What is really important to know for your system and your customer? That
will tell you the best way to get the most useful measurement.
Like the song says - "make it real compared to what!" :-)
Patience, persistence, truth,
Dr. mike
>
> Hi,
>
> This is not related to ADSP but it os a DSP question
> If I have to a noise of 3 DB what is the meaning of that?
> IS it noise power equal to 3DB or SNR equal to 3 DB?
>
> can anyone help me out as I need to test my module with adding noise.
> any links or suggestion for this.
It is definitly not clear. You can boil your question down to "relative"
versus "absolute" difference. decibell is made unitless by taking the
ratio of power levels. You can have a fixed reference like 1 milliwatt
in both cases, and have a 3dB absolute noise level or SNR. In the first
case you can define the noise to be a 1/f distribution or "white" between
certain bounds or even gaussian distribution. 3 dB can be measured
relative to that definition for an absolute measure of noise. Or you can
have a 1 kHz tone at 1 milliwatt and measure your noise level relative to
that and it's one possible SNR measure.
What is really important to know for your system and your customer? That
will tell you the best way to get the most useful measurement.
Like the song says - "make it real compared to what!" :-)
Patience, persistence, truth,
Dr. mike
