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I have probably amateurish problem. Assume that we have a USB tuner DVB-T + connected antenna.

I would like to write a program that will detect the signals of at most a few milliseconds.

Signal looks classically as follows:

enter image description here

Someone can help me how to do it? I want to write it in C.

Edit: I do not need, of course, the final code. I need ideas.

Edit-2:

I add details of the signal:

Frequency: approx. $850 MHz$ (may be more)

The measurement of dispersion: $> 250 pc.cm^{-3}$

The length of the signal: $> 0.01 ms$

Peak Flux: (I'm not sure what value we can get)

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    $\begingroup$ Hi Aurelio, welcome to this website! There's a small problem with your question, namely that asking for code written to a specification is off-topic. However, I'm pretty sure you can re-phrase your question to make it read more like a description of the problem you're trying to solve, explains what you've tried so far, and what your general approach has been, and thus would allow us to answer to your problems specifically :) $\endgroup$ – Marcus Müller Feb 23 '17 at 18:43
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    $\begingroup$ Also: does that have anything to do with DVB-T ? I'm not really able to figure out the relation of DVB-T and your question. The signal you're referring to doesn't look like a DVB signal at all. $\endgroup$ – Marcus Müller Feb 23 '17 at 18:46
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    $\begingroup$ ahhh you're referring to abusing the RTL DVB-T dongles!!! I thought you were referring to DVB (as in digital video broadcast, the TV standard). Please don't mix terms up that much! $\endgroup$ – Marcus Müller Feb 23 '17 at 19:47
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    $\begingroup$ It's not "the DVB-T". It's "a DVB-T dongle used as SDR" $\endgroup$ – Marcus Müller Feb 23 '17 at 19:48
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    $\begingroup$ Yes. Sorry for my mistake. $\endgroup$ – Aurelio Feb 23 '17 at 19:51
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Your C program can link to librtlsdr (source available on github), set the frequency and sample rate, then filter the incoming IQ sample stream from the RTL USB dongle (demodulate if necessary), and (one possibile algorithm out of many) implement an envelope matched filter.

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