[SciPy-user] Convolve an input with a seri of impulses

Ivo Maljevic ivo.maljevic@gmail....
Tue Apr 21 06:10:36 CDT 2009


Mickael,
I do not know why you have to characterise your LTI system in a such way. I
would probably
find an impulse response of the system characterised with num and den using
filter() and than
I would have full control. I am only guessing that you are trying to
describe an analog system,
and this is probably a convenient way, but one I never use. See if the time
output has a different
sampling rate (tout variable) than the time axis I've added. In this case
you would have to use tout
and set your pulse sequence to zeros at the appropriate points.

All I'm saying is that you have more work to do there.

Ivo

2009/4/21 Mickael <mickael.paris@gmail.com>

>
>
> 2009/4/20 Ivo Maljevic <ivo.maljevic@gmail.com>
>
> I never use LTI systems defined in this way, but out of curiosity I tried
>> to make some changes into my original code in a hope I will learn something
>> and help you in a way.
>>
>> Try the attached script, it uses your code.
>>
>> Ivo
>>
>> 2009/4/20 Mickael <mickael.paris@gmail.com>
>>
>>> Hi,
>>>
>>>
>>> I'm trying to convolve a reference signal, like a step signal, with a
>>> sequence of impulses.  Impulses have different amplitudes and timing :
>>>
>>>
>>> ----------------------------------------------------------------------------
>>> zeta = 0.0193
>>> wn = 35037.0
>>> wd = wn*math.sqrt(1.0-zeta**2)
>>> K = math.exp(((-zeta*pi)/math.sqrt(1.0-zeta**2)))
>>>
>>> num = array([9.871])
>>> den = array([1,1354,1.228*10**9])
>>> H = signal.lti(num, den)
>>>
>>> # Impulses : amplitudes
>>> A1 = (1.0/(1.0+K))
>>> A2 = (K/(1.0+K))
>>> # Impulses : timing
>>> t1 = 0
>>> t2 = (pi/wd)
>>>
>>> -----------------------------------------------------------------------------
>>>
>>> I would like to apply to "H" the result of a step signal convolve with
>>> these two pulses but I'don't know to define the vector of the impulses.
>>> --->T,yout,xout = signal.lsim(H, entree, t)  <=== entree = scipy.signal.
>>> convolve(*A_step*, My_Impulses?, mode='full')
>>>
>>> Thanks,
>>>
>>> Mickael.****
>>> _______________________________________________
>>> SciPy-user mailing list
>>> SciPy-user@scipy.org
>>> http://mail.scipy.org/mailman/listinfo/scipy-user
>>>
>>>
>>
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>> Hi Ivo,
>
> thank you very much for your help.
>
> i will try your code today and post the result
>
> thanks,
>
> Mickael.
>
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