[time-nuts] TIC resolution impact on GPSDO's performance

Poul-Henning Kamp phk at phk.freebsd.dk
Tue Dec 26 08:18:13 EST 2006


In message <20061226.125102.1723212534.cfmd at bredband.net>, Magnus Danielson wri
tes:

>harmonic(2)
>1a) a tone in a harmonic series
>2) in physics, a component frequency of a harmonic motion that is an integral
>   multiple of the fundamental frequency
>
>overtone
>1b) Harmonic(2)

Overtone is a musical term and it is not the same as harmonic.

An harmonic frequency is N times the fundamental, where as an
overtone merely holds a rational relationship to the fundamental
(3/2, 4/3 etc.)

The reason you can tell the difference between a violin and a
clarinet is that they have different overtone spectra.

A somewhat arbitrary subset of an intruments overtones are called
"formants" because they are the principal "formers" of the instruments
sound.

>synchronous
>1) happening, existing or arising at precisely the same time
>2a) going on or operating together at exactly the same rate
> b) recurring together
>3) involving or indicating synchronism


>4) in physics, having the same period or having the same period and phase

Close, but no cigar.

If they merely have the same period/frequency, they are "syntonous",
but if the phase is also coincident, they are synchronous.

>asynchronous
>not synchronous, proceeding at its own pace; 

But just because two signals are asynchronous, doesn't mean they cannot
have the same frequency or phase for a shorter or longer period of time,
it just means that there is no mechanism that makes it so.

>The "asynchronous" serial line is actually anisochronous BTW.

No, each transmitter and receiver are anisochronous, but the
communication between them, and by language extension the actual
cable, is asynchronous.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.



More information about the time-nuts mailing list