[sdiy] 5mV of noise ...

[JH.]

I don't know how it was measured - it might just be the scope's own noise.
Not uncommon even on expensive scopes, because of the wide bandwidth.

JH.


----- Original Message ----- 
From: "Magnus Danielson" <cfmd at bredband.net>
To: <bert at percussa.com>
Cc: <synth-diy at dropmix.xs4all.nl>
Sent: Thursday, June 16, 2005 11:40 PM
Subject: Re: [sdiy] 5mV of noise ...


> From: "Bert Schiettecatte" <bert at percussa.com>
> Subject: [sdiy] 5mV of noise ...
> Date: Thu, 16 Jun 2005 23:15:53 +0200
> Message-ID: <004701c572b8$941266b0$4101a8c0 at laptop>
>
> > Hi all,
> >
> > I have a silly question so don't shoot me. I'm still learning on analog
> > stuff.. I have been breadboarding some audio circuitry and I measured
> > between 4mV and 5mV of noise. Exactly how bad is this? Of course I could
> > convert this into dB I suppose but even then I'm not sure how bad this
> > is once you start passing sound through it.
>
> If your referens level is 775 mV, a noise of 5 mV(RMS) equals -43.8 dBm.
This
> is bad. That's only 43.8 dB of dynamics. OK, let's say you have 6 dB of
head-
> room but that only gives you 50 dB of dynamics. OK, if you like the
dynamics
> of tape-recorders it may fit your needs, but you can do alot better.
>
> Cheers,
> Magnus
>