Subject: Re: [linux-audio-dev] off topic, optical protocols
From: Ruben van Royen (rvroyen_AT_guidedbees.com)
Date: Tue Mar 05 2002 - 12:43:50 EET
Hi,
I thought, thats interesting, lets do a search on google. So I search for
digital microphone. And came up with: http://www.ptang.com/digmic/showpatimg
For those who don't want to bother with the link: It's a patent for
putting the A/D converter in the microphone housing! Guess Neumann will have
a patent problem with their new Solution-D.
It shows again: those patents are rediculous.
Ruben
On Tue, Mar 05, 2002 at 08:56:42AM +0000, Nick Bailey wrote:
> actuallyt you can get digital microponones: they measure the
> displacement of the diaphram by counting fringes on a laser
> interferometer, so there never is an analogue signal (except
> the physical movement of the membrane itself).
>
> Damned if I can find a reference to it now... I hope it
> wasn't an April Fools' Day joke 8-)
>
> I think there may be switched-mode audio power amplifiers
> too, but I doubt they will ever be HiFi compared with high
> end linear designs.
>
> N/
>
>
> On Tuesday 05 Mar 2002 4:34 am, you wrote:
>
> > Well, you'll have to have an A/D converter somewhere in the
> > line. If the optical cable is digital, then the A/D
> > converter would live in the microphone. But there isn't
> > any way to remove the A/D conversion. You wouldn't need a
> > D/A converter unless you wanted to playback.
> >
> > Digital versus analog is orthagonal to electrical versus
> > optical.
> >
> > Taybin
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