On
08/10/2019 10:48 PM, Ellie White wrote:
Hi Marcus,
Thanks for your reply. I am not sure how the
integration works, but if you know how the Integrate
block does the integration, then that is how my
flowgraph does it. I suspect it is "sum /reduce /dump"
as you mentioned, though perhaps we would need to
investigate the Integrate block's source code to be
sure? Thanks in advance for any additional suggestions
you might have on this!
Cheers,
Ellie
Here's the documentation on the integrate block:
https://wiki.gnuradio.org/index.php/Integrate
So, if your samples are coming in at 1kHz, and you want 1
second of integration time (and an output rate of 1Hz),
you'd set the
"decimation" parameter to 1000.
This is one of the reasons I prefer single-pole-IIR
filters--since I can do sample-rate reduction as a separate
process, via keep-one-in-N.
On Sat, Aug 10, 2019
at 7:37 PM Marcus D. Leech <
address@hidden>
wrote:
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.
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