in article 6frua1tqduvj62k95nl0duicanrnh5fs0e@4ax.com, Eric Jacobsen at
eric.jacobsen@ieee.org wrote on 06/14/2005 19:55:

> On Tue, 14 Jun 2005 17:46:32 -0400, robert bristow-johnson
> <rbj@audioimagination.com> wrote:
> 
>> in article JeWdnUmc0YDNmDLfRVn-1g@rcn.net, Jerry Avins at jya@ieee.org wrote
>> on 06/14/2005 12:26:
>> 
...
>>> 
>>> Strictly, "quasi synchronous" means "as if synchronous", which we take
>>> to mean "mostly behaves like synchronous, sort of". "Plesiosynchronous"
>>> means "nearly synchronous", which is not exactly the same thing.
>> 
>> i wonder if i should change my term for musical notes (of a tonal nature and
>> mostly harmonic) that are eligible for reproduction using true wavetable
>> synthesis, from "quasi-periodic" to "plesio-periodic"?
> 
> Are they slowly periodic?
> 
> The "plesio" part of the "nearly synchronous" idea is that the phase
> difference (i.e., the synchronization) between the two clocks or
> references changes very slowly.
> 
> So I'm not sure whether that applies to your synthesis ideas or not.

let

            N
    x(t) = SUM{ r_n(t) * cos(n*w0*t + phi_n(t)) }
           n=1

where r_n(t) and phi_n(t) are both slowly changing functions.  they are both
virtually bandlimited to something much lower than w0.  or

    |(d/dt)r_n| << w0*|r_n|

for the most part (that's a pretty squishy description).  and same for
phi_n(t).

x(t) does have an apparent period of 2*pi/w0 and one cycle or period will
appear virtually indistinguishable from its adjacent period, but will not
look like a cycle 500 or 1000 ms later.  it is certainly not precisely
periodic.

what is x(t)?  is it "quasi-periodic" or "plesio-periodic"?  or something
else?  (i would reject the term "pseudo-periodic".)

-- 

r b-j                  rbj@audioimagination.com

"Imagination is more important than knowledge."

On Tue, 14 Jun 2005 17:46:32 -0400, robert bristow-johnson
<rbj@audioimagination.com> wrote:

>in article JeWdnUmc0YDNmDLfRVn-1g@rcn.net, Jerry Avins at jya@ieee.org wrote
>on 06/14/2005 12:26:
>
>> robert bristow-johnson wrote:
>> 
>> ...
>> 
>>> sometimes jargon is batted around for social reasons.
>> 
>> See "shibboleth".
>> 
>>> i'm still trying to figure out what the difference between "plesiochronous"
>>> and "quasi-synchronous" is and, if there is no difference, why the need for
>>> a new term?
>> 
>> Strictly, "quasi synchronous" means "as if synchronous", which we take
>> to mean "mostly behaves like synchronous, sort of". "Plesiosynchronous"
>> means "nearly synchronous", which is not exactly the same thing.
>
>i wonder if i should change my term for musical notes (of a tonal nature and
>mostly harmonic) that are eligible for reproduction using true wavetable
>synthesis, from "quasi-periodic" to "plesio-periodic"?

Are they slowly periodic?

The "plesio" part of the "nearly synchronous" idea is that the phase
difference (i.e., the synchronization) between the two clocks or
references changes very slowly.

So I'm not sure whether that applies to your synthesis ideas or not.

Eric Jacobsen
Minister of Algorithms, Intel Corp.
My opinions may not be Intel's opinions.
http://www.ericjacobsen.org

] p.s. period stems from Greek, so plesioperiodic would be more
] correct than quasiperiodic.

Taken from:

http://dictionary.reference.com/search?q=Period

we have:

[Middle English periode, from Old French, from Medieval Latin periodus,
from Latin perihodos, rhetorical period, from Greek periodos, circuit
: peri-, peri- + hodos, way.]

Looks to me like this is saying that there are both Greek and Latin
etymologies.

:-)

Ciao,

Peter K.

"robert bristow-johnson" <rbj@audioimagination.com> wrote in message 
news:BED4C877.8475%rbj@audioimagination.com...
> in article JeWdnUmc0YDNmDLfRVn-1g@rcn.net, Jerry Avins at jya@ieee.org 
> wrote
> on 06/14/2005 12:26:
>
>>
>>> i'm still trying to figure out what the difference between 
>>> "plesiochronous"
>>> and "quasi-synchronous" is and, if there is no difference, why the need 
>>> for
>>> a new term?

Robert,

The difference is you are mixing languages.

Plesiochronus and synchronous have Greek roots. The "plesiochronous problem" 
has been around for a long time (even referred to by that name). It is the 
basic problem of synchronizing clocks around the world.


Quasi comes from Latin.

The word purests would hate to see a mixing of the languages when building 
new words.

Of course we are in a world where computer people say "insert the media" 
when they are only going to insert a single solitary thing. It is a medium 
and not a media. And this is the same world where Nissan names a car the 
Maxima. Yeap, they gave a plural name to a singular object. I think more 
people should study some basic Greek and Latin, and if they don't, they 
should simply try to see if a word already exists before creating a bastard 
that adds yet another exception to the list of exceptions.

My two cents worth.

Clay

p.s. period stems from Greek, so plesioperiodic would be more correct than 
quasiperiodic.




>>
>> Strictly, "quasi synchronous" means "as if synchronous", which we take
>> to mean "mostly behaves like synchronous, sort of". "Plesiosynchronous"
>> means "nearly synchronous", which is not exactly the same thing.
>
> i wonder if i should change my term for musical notes (of a tonal nature 
> and
> mostly harmonic) that are eligible for reproduction using true wavetable
> synthesis, from "quasi-periodic" to "plesio-periodic"?
>
> -- 
>
> r b-j                  rbj@audioimagination.com
>
> "Imagination is more important than knowledge."
>
> 

"Jerry Avins" <jya@ieee.org> wrote in message
news:W5WdnXxRAYBG8jLfRVn-tQ@rcn.net...
>
> That depends on whether the music dwives you quasi, or if you find it
> plesing.

Wow, that is bad!  (I mean that in a good way.)

robert bristow-johnson wrote:
> in article JeWdnUmc0YDNmDLfRVn-1g@rcn.net, Jerry Avins at jya@ieee.org wrote
> on 06/14/2005 12:26:
> 
> 
>>robert bristow-johnson wrote:
>>
>>...
>>
>>
>>>sometimes jargon is batted around for social reasons.
>>
>>See "shibboleth".
>>
>>
>>>i'm still trying to figure out what the difference between "plesiochronous"
>>>and "quasi-synchronous" is and, if there is no difference, why the need for
>>>a new term?
>>
>>Strictly, "quasi synchronous" means "as if synchronous", which we take
>>to mean "mostly behaves like synchronous, sort of". "Plesiosynchronous"
>>means "nearly synchronous", which is not exactly the same thing.
> 
> 
> i wonder if i should change my term for musical notes (of a tonal nature and
> mostly harmonic) that are eligible for reproduction using true wavetable
> synthesis, from "quasi-periodic" to "plesio-periodic"?

That depends on whether the music dwives you quasi, or if you find it 
plesing.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������

in article JeWdnUmc0YDNmDLfRVn-1g@rcn.net, Jerry Avins at jya@ieee.org wrote
on 06/14/2005 12:26:

> robert bristow-johnson wrote:
> 
> ...
> 
>> sometimes jargon is batted around for social reasons.
> 
> See "shibboleth".
> 
>> i'm still trying to figure out what the difference between "plesiochronous"
>> and "quasi-synchronous" is and, if there is no difference, why the need for
>> a new term?
> 
> Strictly, "quasi synchronous" means "as if synchronous", which we take
> to mean "mostly behaves like synchronous, sort of". "Plesiosynchronous"
> means "nearly synchronous", which is not exactly the same thing.

i wonder if i should change my term for musical notes (of a tonal nature and
mostly harmonic) that are eligible for reproduction using true wavetable
synthesis, from "quasi-periodic" to "plesio-periodic"?

-- 

r b-j                  rbj@audioimagination.com

"Imagination is more important than knowledge."

Everett M. Greene wrote:

>  ,,.  Now someone has added plesiochronous to this group's
> discussions.

   ...

I found these definitions on the web:

plesiosynchronous - sipping a cosmopolitan on the beach while the cabana 
boy rubs oil on my back and the waves lap upon the shore. very pleasing 
synchronous activities for all the senses.

"plesiosynchronous" is a phrase often uttered by Mexican sardines as a 
help to novice fishermen trying to bait them on a hook. Roughly 
translates to "Please, Yo, sinker on us".

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������

> i'm still trying to figure out what the difference between "plesiochronous"
> and "quasi-synchronous" is and, if there is no difference, why the need for
> a new term?

The impression I got was that plesiochronous was closer to being synchronous
than quasi-synchronous, i.e. less drift, but I could be wrong.  There really
doesn't seem to be a need for a new term, yet we have it.  Actually, in audio
I've been dealing with "plesiochronous" systems for years without having/needing
any word for them.  You would just say the 2 systems have the same nominal
sample rate but aren't locked together.  It is the comms guys that seem to have
popularized "plesiochronous" and now it is being used in audio as well.

robert bristow-johnson wrote:

   ...

> sometimes jargon is batted around for social reasons.

See "shibboleth".

> i'm still trying to figure out what the difference between "plesiochronous"
> and "quasi-synchronous" is and, if there is no difference, why the need for
> a new term?

Strictly, "quasi synchronous" means "as if synchronous", which we take 
to mean "mostly behaves like synchronous, sort of". "Plesiosynchronous" 
means "nearly synchronous", which is not exactly the same thing.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������