[sdiy] 440Hz Reference Oscillator.

[Magnus Danielson]

From: Scott Gravenhorst <music.maker at gte.net>
Subject: Re: [sdiy] 440Hz Reference Oscillator.
Date: Tue, 06 Jun 2006 16:47:16 -0700
Message-ID: <200606062347.k56NlEk18163 at linux7.lan>

> I believe the WWV plays an A 440.

Only sometimes. ;O)

http://tf.nist.gov/stations/iform.html

That'l be 24 times a day and only for 960 ms each. It will be a long tuning.

While WWV and WWVH is all nice and dandy, they are not really to be counted on
on as a world-wide generic tuning-mechanism. I can usually haul my laptop to
the same places as my synths. That suffice.

Cheers,
Magnus

> 
> Magnus Danielson <cfmd at bredband.net> wrote:
> >From: Ian Fritz <ijfritz at earthlink.net>
> >Subject: Re: [sdiy] 440Hz Reference Oscillator.
> >Date: Tue, 06 Jun 2006 15:33:03 -0600
> >Message-ID: <6.2.1.2.2.20060606153008.02c1ffa8 at mail.earthlink.net>
> >
> >Ian,
> >
> >> The "A" you get from the telephone co is accurate.  You could probably run 
> >> it through a filter to get a sine.
> >
> >Ehm... only if they actually "play" A. Not all do you know. ;O)
> >
> >Infact, chances are that they not necessarilly have a musical note frequency.
> >
> >Just look in ETSI EN 300 001 (go ahead and download it if you like, you need to
> >get the password, but it's free) and be amazed over the variation, and I am
> >sure that things have shifted away from that one. Sigh.
> >
> >Whatever frequency synthesis they do, it may be any form of approximation
> >(consider the ration 8000 / 440 which becomes 18.181818... samples/wawe).
> >What you can count on is the stability, which should be sufficient for musical
> >applications, even with them new VoIP phones you should at least have a lousy
> >+/- 100 ppm crystal.
> >
> >So, not without proper verification. Hmm. I haven't done that test yeat!
> >
> >Telephone is a degrading service... sigh!
> >
> >Cheers,
> >Magnus
> >
> 
> ---------------------------------------------------------
> - Where merit is not rewarded, excellence fades.
> - Hydrogen is pointless without solar.
> - What good are laws that only lawyers understand?
> - The media's credibility should always be questioned.
> - The only good terrorist is a dead terrorist.
> - Governments do nothing well, save collect taxes.
> 
> -- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
> -- Linux Rex         | RedWebMail by RedStarWare
> -- FatMan: home1.gte.net/res0658s/fatman/
> -- NonFatMan: home1.gte.net/res0658s/electronics/
> -- Autodidactic Master of Arcane and Hidden Knowledge.
>