Java Audio question - PLEASE HELP

On Apr 23, 2:48&#4294967295;pm, "cpptutor2...@yahoo.com" <cpptutor2...@yahoo.com>
wrote:
> With reference to all the postings I am sorry I have caused confusion..

One way to 'cut through the c..onfusion' is to post an
SSCCE.  More info here
http://sscce.org/

Have one peice of code to generate the tone,
and a second to do the transform.

--
Andrew T.

Andrew Thompson wrote:
> http://sscce.org/

Swee-eet.

-- 
Lew

Lew wrote:

> cpptutor2000@yahoo.com wrote:
>> On Apr 22, 11:04 pm, Lew <l...@lewscanon.com> wrote:
>> 
>>>>    fs = sample rate in Hz
>>>>    dT = 1/fs = interval between samples
>>>>    N = number of samples taken
>>>>    T = N x dT = total time period
>>>>    f1 = 1/T = frequency of the first harmonic in Hz
>>> So if you accumulated twice as many samples, over twice as long, your
>>> fundamental frequency would be halved?  That is not sensible.
>>>
>>> --
>>> Lew
>> That is precisely the case. Please check the definitions above. Please
>> note that f1 is the first harmonic if I were to calculate an FFT with
>> the collected samples. The fundamental frequency is 500.0 Hz, and
>> stays that way.
> 
> No, that doesn't make sense.  If I recorded a pure 1000 Hz sine wave, that is 
> the frequency whether I take 44000 samples for one second or 88000 samples 
> over two seconds.  The frequency isn't affected by how long I record it.
> 

The frequency *resolution* is, though. That's what the OP was referring to
[rather obliquely]. The OP mistakenly calls this the fundamental frequency. 

The sampling rate determines the bandwidth, and the maximum freq. which you can
capture (Nyquist-Shannon). The overall length (in time, not samples) determines
the frequency resolution (Fourier).

-- 
Nigel Wade

Jerry Avins wrote:
(snip)

> It would help if you used the same terms that the rest of us do. In 
> particular, it is important to avoid using standard words in 
> non-standard ways without the sort of glossary you provided here.

> *Fundamental* applies not to an FFT, but to the longest-period component 
> of a periodic waveform. What *you* have called the fundamental is often 
> referred to as bin width or resolution.

It does make some sense in the context of the FFT, though.
Since FFT has periodic boundary conditions, the lowest non-zero
frequency could be considered the fundamental.  Those who
apply the FFT to non-periodic signals get what they deserve.

> If your signal repeats every 2 ms, then its fundamental is 500 Hz. It 
> may have harmonics at 1000, 1500, 2000Hz, etc.

-- glen

On Apr 24, 1:16 pm, glen herrmannsfeldt <g...@ugcs.caltech.edu> wrote:
> Jerry Avins wrote:
>
> (snip)

 > > snip

> It does make some sense in the context of the FFT, though.
> Since FFT has periodic boundary conditions, the lowest non-zero
> frequency could be considered the fundamental.

In the OP's description, 500 Hz is the lowest non-zero frequency :,).
And it is the 'fundamental of the signal', as opposed belonging to the
set of 'fundamental frequencies of the transform', of which zero is
included as a member.

Does anyone have a suggestion for a description of this area of
vocabulary that is:
1) accessible (free, etc.)
2) complete enough for this level of discussion
3) unambiguous
4) at a suitable level for the OP?

> Those who
> apply the FFT to non-periodic signals get what they deserve.
>

Those who have known how to apply the FFT to non-periodic signals have
made much good use of it.

> -- glen

Dale B. Dalrymple

On Apr 24, 4:33&#4294967295;pm, Lew <l...@lewscanon.com> wrote:
> Andrew Thompson wrote:
> >http://sscce.org/
>
> Swee-eet.

I thought you (amongst others) might like that URL.

It is Dave Minter's mirror of the SSCCE.  Thanks Dave!

--
Andrew T.