[PD] phasor~ usage question

[Frank Barknecht]

Hallo,
PSPunch hat gesagt: // PSPunch wrote:

> Can someone please give me a bit of info regarding the example
> illustrated in the page,
> http://crca.ucsd.edu/~msp/techniques/latest/book-html/node198.html
> 
> 
> > Each parabolic wave is computed from a sawtooth wave (ranging from
> > -0.5 to 0.5) by squaring it, multiplying by 0.5, and subtracting
> > the DC component of -1/12, or -0.08333.
> 
> I could not quite understand where this offset of 0.08333 comes from.
> Are there any descriptions of the theory behind this?

The theory for this technique is here: 
http://crca.ucsd.edu/~msp/techniques/latest/book-html/node187.html
especially the equation for the parabolic wave below Fig. 10.4

The 0.08333 in the patch is 1/24 times 2: 
2 * 1/24 = 0.083333333333333

Basically the whole construct below each [wrap~] is just the equation
from there in Pd patch format.

> Also, this example has a message connected directly to [phasor~] while a
> good number of other samples (including the [phasor~] help file) has a
> [sig~] in between.
> Is there any difference in the behavior?

Not really: Numbers directly connected to [phasor~]'s first inlet get
converted to a constant signal inside of [phasor~] automatically now.
IIRC this wasn't the case for older versions of Pd, and then you had
to use a [sig~] in between to do the conversion from message to
signal.

Ciao
-- 
 Frank Barknecht                                     _ ______footils.org__