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muccc / gr-iridium

Iridium burst detector and demodulator.
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Online overflow detection #49

Closed marcusetchart closed 2 years ago

marcusetchart commented 4 years ago

Hi!

I am using gr-iridium with hackrf (iridium-extractor -D 4 examples/hackrf.conf | grep "A:OK" > output.bits) and it works right.

Does anyone know how I can detect overflow during the online processing?

when I see "Detector in burst squelch at xxxx", first I have to check that it is not an interference, haven't I? (issue 26)

Thanks a lot in advanced. BR Marcus

schneider42 commented 4 years ago

There are two kinds of "overflows":

The first one happens when there are burst detected on more than 80% the available bandwidth which I think will never be the case with Iridium. The only indication that this happened is the message you mentioned above. The second one happens when there are more than 500 bursts pending to be processed (per gr-iridium internal channel). Dropped bursts are counted in the d: part of the statistics.

Assuming that your issue is with the burst squelch. I'd suggest to try (some of) the following options:

I'm happy to look at a raw IQ capture if you can provide one.

schneider42 commented 4 years ago

I have to correct myself, there is a third kind of overflow: When there is not enough CPU/memory bandwidth available to create the detected bursts. Depending on the SDR you will see Os being printed (rtl-sdr, hackrf) or no indication at all (bladerf). These overflows are not tracked in the statistics and can have the following causes:

marcusetchart commented 4 years ago

Thank's Sec for your soon and clearly response.

I will try to take a raw IQ capture for you.

marcusetchart commented 4 years ago

sorry, thank's Schneider!!!