Re: [Signal PKG] limited slope

[Renato S. Yamane]

2017-12-15 16:34 GMT+01:00 Robert T. Short <address@hidden>:
> On 12/15/2017 12:27 AM, Renato S. Yamane wrote:
>> 2017-12-14 20:25 GMT+01:00 Robert T. Short
>>> On 12/13/2017 11:39 PM, Renato S. Yamane wrote:
>>>> Please, see the frequency response on image available in:
>>>> https://ibb.co/cgwOqG
>>>>
>>>> Detail: when I use a crest factor of 12dB instead 6dB, I don´t have
>>>> this problem.
>>>>
>>>> ==============
>>>> pkg load signal;
>>>> pkg load ltfat;
>>>>
>>>> sampling_rate = 44100;
>>>> lenght = 30;
>>>> hpf = 400;
>>>> lpf = 4000;
>>>> crest_factor = 6;
>>>>
>>>> typenoise = noise((lenght)*sampling_rate, 1, 'pink');
>>>> [b,a] = butter(2, [hpf/(sampling_rate/2), lpf/(sampling_rate/2)]);
>>>> filtered = filter(b, a, typenoise);
>>>> filtered = filtered / (rms(filtered) / 10^(-crest_factor/20));
>>>> audiowrite ('signal.wav', filtered, 44100);
>>>> ==============
>>>
>>>
>>> I don't get the same spectral plots you show here.  My results are much
>>> more
>>> like your "expected" slope.
>>
>>
>> Wowww!
>> Can you tell me how you plot it? Just to be possible I make the same
>> check here in my side...
>
>
> Well, I used a Welch's method estimator to get the spectral density.  I used
> a Hamming window, but just about any window should do.  I didn't use any
> overlap.  There is such an estimator as part of octave.  Then I just plotted
> it.  I did a semilogx just like you did and only for frequencies > 1Hz.

Sorry, but can you help me with this "coding" that you did?

Have a good day,
Renato