FftLab Java Applet - Revisited

One thing that I noticed is that if you drag the magnitude DC bin up, it creates
a DC offset on the Real input samples, as expected.  What wasn't intuitive to me
was that no matter what size I made the DC bin, the Real DC offset was the same
apparent magnitude, rather than being scaling with magnitude.  Upon a little
further experimentation, it looks like there is some auto-scaling going on.

"Stephan M. Bernsee" <spam@dspdimension.com> wrote in message
news:42c34ef.0407010926.582a481d@posting.google.com...
> Hmm, I'm not sure what you mean... you can click and drag the mouse
> within these "lollipop" displays to change the curves... is that what
> you're referring to? That's the whole point about the applet. Do you
> find that in any way unclear?
>
> --smb
>
> Bernhard Holzmayer <holzmayer.bernhard@deadspam.com> wrote in message news:
> >
> > It took some time until I happened to find out that curves can be
> > modified using the mouse pointer.
> >
> > I'd propose that you add a hint for newbies...
> >
> > Bernhard

Stephan M. Bernsee wrote:

> I've included a downloadable offline version on that page.
> 
> --smb

1st item. *THANK YOU*
     I'm a 'visual learner' and formal math leaves me lost ;{

2nd item. (Here I may demonstrate my Java ignorance)
     Could you post the source code?
     (Would it be as useful as I might think?)
         [ Mr. Holzmayer's post seemed to imply source would be
           intrinsically available.]

My immediate objective:

Add option to 'Editing' drop down menu which would allow entering an 
analytic function rather than a freehand drawn approximation.

My underlying objective:

I am totally lost when considering
   'windowing'
      and/or
   'DFT Leakage'
      and/or
    etc.
Rick Lyons , Jerry Avins, and others have spent much time trying to 
verbally explain things to me.

An immediate partial goal.

FORCE input samples ( top left sub-window ) to be an arbitrarily 
defined function. ( imaginary values == 0 )

A typical use would be to reproduce Figure 3-7/3-8 of _Understanding 
Digital Signal Processing_ 2nd Edition by R. Lyons ( and arbitrary 
variants)

Have I expressed  myself clearly?

Stephan M. Bernsee wrote:

> Hmm, I'm not sure what you mean... you can click and drag the
> mouse within these "lollipop" displays to change the curves... is
> that what you're referring to? That's the whole point about the
> applet. Do you find that in any way unclear?
> 
> --smb

Yes. It happened like this:
At first glance, I noticed the selection gadgets on the bottom.
Very little happened when I played with them.
So I reckoned there must be more about it, and it just happened that 
I clicked into one of the drawings while 'draw' mode was active.
I was stunned: the curve changed. 
Tried it again: oohh!

There would have been good chance, that I wouldn't have tried to 
click into the curve canvases, because they look like 
'display-only' elements which would not accept input.

That's not obvious to a typical GUI user.
I wouldn't have bothered. But I did, because you need to know, or 
you can't use the applet. 

Tiny note saying something like: "use mouse on curves" would help.
Or, if you don't want to spoil the window by such a thing, 
a message box opening once in the beginning of the first session,
might give some explanations...


Bernhard  

Thanks for the suggestions. I will put them on my list of to-do items
for the page since I will require some time to implement them, and I
don't have much spare time at the moment. Especially the playback
option and the evaluation of expressions would make very nice
additions.

--smb

Thanks for the suggestions. I will put them on my list of to-do items
for the page since I will require some time to implement them, and I
don't have much spare time at the moment. Especially the playback
option and the evaluation of expressions would make very nice
additions.

--smb

Ok, all valid points. I know that as the creator of something you
usually know how to use it (obviously), but even so I figured it might
be obvious - maybe because it was to me when I first came across Dave
Hale's applet (who wrote the original version).

At any rate, thanks for the feedback, I'll include a brief how-to on
that page soon.

--smb

Bernhard Holzmayer <holzmayer.bernhard@deadspam.com> wrote in message news:<1402350.nzUpPJ8bNS@holzmayer.ifr.rt>...
> Stephan M. Bernsee wrote:
> 
> > Hmm, I'm not sure what you mean... you can click and drag the
> > mouse within these "lollipop" displays to change the curves... is
> > that what you're referring to? That's the whole point about the
> > applet. Do you find that in any way unclear?
> > 
> > --smb
> 
> Yes. It happened like this:
> At first glance, I noticed the selection gadgets on the bottom.
> Very little happened when I played with them.
> So I reckoned there must be more about it, and it just happened that 
> I clicked into one of the drawings while 'draw' mode was active.
> I was stunned: the curve changed. 
> Tried it again: oohh!
> 
> There would have been good chance, that I wouldn't have tried to 
> click into the curve canvases, because they look like 
> 'display-only' elements which would not accept input.
> 
> That's not obvious to a typical GUI user.
> I wouldn't have bothered. But I did, because you need to know, or 
> you can't use the applet. 
> 
> Tiny note saying something like: "use mouse on curves" would help.
> Or, if you don't want to spoil the window by such a thing, 
> a message box opening once in the beginning of the first session,
> might give some explanations...
> 
> 
> Bernhard