Re: [Discuss-gnuradio] Question about calculating integration times

[Marcus D. Leech]

On 08/10/2019 03:40 PM, Ellie White wrote:
> Hi all,
>
> I hope you're doing well! Thanks again for your help with my questions 
> earlier this summer. I've got another thing to ask now; I am in the 
> process of configuring a system to record integrated spectra using the 
> attached flowgraph, and I am trying to determine how to integrate for, 
> say, 60 seconds -- if I want to do this, what should my decimation be, 
> and how do I calculate that? I have been able to approximate this by 
> trial and error, but I would like to know the calculation behind it.
>
> Thanks in advance for any advice you can provide, much appreciated. 
> Have a good afternoon!
>
> Cheers,
> Ellie
It kind of depends on how you're doing integration.

An approach that strictly does sum/reduce/dump then you need as many 
samples as would occur over your desired integration time.

For a single pole IIR filter, it's a bit trickier, and you'd set the 
"Alpha" parameter to:

e^sqrt(sample-rate*integraton-time)

Which will approximate an R-C integrator with  the given integration time.