Oh, one more thing... with the fftscope-Patch there's a warning displayed when you first bang the procedure. This is because of a small bug in the new threading behavior of flext. I fixed it - the version should be mirrored to the pd cvs in about half an hour.
best greetings, Thomas
----- Original Message ----- From: "Larry Troxler" lt@westnet.com To: "Thomas Grill" t.grill@gmx.net; "PD List" pd-list@iem.kug.ac.at Sent: Monday, November 10, 2003 3:22 AM Subject: Re: Some VASP questions
On Sunday 09 November 2003 20:36, Thomas Grill wrote:
You can either send a "detach 1" message before the first operation, or even better, set the "detach" attribute at creation time by specifying
e.g.
[vasp.window @detach 1]. If you have newer vasp and pd versions, you
will
notice that the "@detach 1" disappears, but you can use the properties dialog in the context menu (right mouse click) to display the attributes
of
vasps objects (or rather all attribute-enabled flext objects)
<various stuff snipped for your concise viewing pleasure>
detach
Ok, I didn't know you could do that at creation time - that's what I want.
Next, "vasp.window" apparently doesn't handle the "to" message
vasp.window fills a buffer with a window curve, so a separate
destination
won't make much sense. There's vasp.*window to multiply half of a window with some data, or vasp.*xwindow for a symmetric version (these two have a @to attribute)
Yes, I misunderstood - I thought that that vasp.window already multiplied
the
existing buffer with its window.
Now about the fft stuff - I am not sure what vasp.rfft does actually.
It
the vasp.rfft operation produces the following output bin 0 .... frequency 0 component bin 1... windowsize/2-1 ... real part of the spectrum (only positive frequencies) bin windowsize/2 ... Nyquist freqency component bin windowsize/2+1... windowsize-1 ... complex part of the spectrum
(only
positive frequencies)
There's no redundancy of data as expected for a real FFT. A magnitude operation has to be performed separately afterwards.
IOW basically, for an FFT of a real signal, I only want the first
half,
See the attached patch... it probably does what you want to do....
best greetings, Thomas
Taking a look in 3.. 2.. 1..
Larry