Re: ADSBSpy Output format


RE: The basic problem I have with that is presuming the 20 MHz means 50 ns when you get I and Q at 10 MHz. I alone and Q alone don't give you a meaningful time.

The Airspy hardware/firmware does not generate or use I/Q. The ADC in the hardware does not and cannot sample in quadrature.  There is a single 12 bit ADC which is set to sample at 20MSPS/20Mhz/50nS real. It can be set to sample at other rates, but 20MSPS is the most that you can reliably push out over an USB2 interface. Youssef has now confirmed the decoder runs 20MSPS real, so I don't have a dog in the "is 20MSPS real to 10MSPS I/Q is possible" fight.  However, if it's not possible, then how do you think  SDRSharp works @ 10MSPS I/Q with an Airspy?

RE : Argue with Youssef. Are you absolutely certain that the multiple packets do not represent multiple transmissions?

Yes - I'm as certain as Schrodinger and Heisenberg will allow anybody to be about anything. Anyhow, Youssef has kindly supplied me some extra information which will allow me to investigate. If I find anything useful then I'll feed it back to him so he can decide whether to incorporate it in airspy-adsb.

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