>westocl wrote:
>>> westocl wrote:
>>>>> westocl wrote:
>>>>>>> westocl wrote:
>>>>>>>> Hello all.
>>>>>>>>
>>>>>>>> Is it feasable to do an fft in 'real time' on different 'blocks'
>> of
>>>>>> data?
>>>>>>>> (i understand the nomenclature real time may be inappropriate).
>>>>>>>>
>>>>>>>>
>>>>>>>> Im thinking, in general usage of an FFT, some x[n] comes in one
>>>> sample
>>>>>> at
>>>>>>>> a time and fills up a buffer and when that buffer (lets call it
>> 128
>>>>>> time
>>>>>>>> domain samples) is filled a FFT is taken and the 'output' is 128
>>>> points
>>>>>> of
>>>>>>>> frequncy domain data.
>>>>>>>>
>>>>>>>> Now.. instad of somthing like a sliding DFT where a window
>> evaluates
>>>>>> the
>>>>>>>> previous 127 samples along with one new one, i have a situation
>>>> where
>>>>>> i
>>>>>>>> want to give the 'fft buffer' 128 NEW data points... so every
>> single
>>>>>> 'time
>>>>>>>> instant'...128 new x[n] data are available.
>>>>>>>>
>>>>>>>> If this were done would I get a new FFT output at every time
>>>> instant?
>>>>>>> You confused me. 128 new instances of x[n] for every n? How?
>>>>>>>
>>>>>>> Jerry
>>>>>>> --
>>>>>>> Engineering is the art of making what you want from things yo
can
>>>> get.
>>>>>> You are right...My notation is somewhat confusing by using x[n].
>> But
>>>>>> imagine we had a switch that will switch to an already ful
buffer
>> at
>>>>>> every 'sample interval'. Then at the next instant we go to th
next
>>>> 128
>>>>>> buffer and we call that x[n] and so on..
>>>>> What fills these nearly full buffers? When? You seem to want 128 ne

>>>>> samples per sampling instant. That can't be sustained.
>>>>>
>>>>> Jerry
>>>>> --
>>>>> Engineering is the art of making what you want from things you can
>> get.
>>>>
>>>> It seems thats exactly the case i will have... What i want to do is
>>>> analagous to having 128 antennas and a situation where i have t
take
>> the
>>>> FFT for each antenna. So some kind of rotary switch gives me the new
>>>> antenna input data at every sample... and will keep spinning.
>>> There's nothing unusual about simultaneously processing multiple
>>> streams. But each stream would have it's own FT. There could be 128
>>> samples collected at each sample interval, but probably not via a
>>> multiplexer (rotary switch). One of us is still confused.
>>>
>>> Jerry
>>> --
>>> Engineering is the art of making what you want from things you ca
get.
>>
>>
>> Lets say you wanted to take the FFT of the output of a sliding DFT...
>> heres a situation where you will have new data at every sample.
>>
>> Could this be done?
>
>Yes. What would the FFT of a sliding DFT represent to you? The
>objectives seem to keep changing. What are you exploring?
>
>Jerry
>--
>Engineering is the art of making what you want from things you can get.


I dont mean to sound allusive... I was jut saying that is how you can loo
at the processing i am trying to do.. constantly having differnt blocks o
data in which to process.