[Hackrf-dev] How to correlate received RF-Signal with reception time (GPS based) in a deterministic way for further processing of both information?

[Andreas Hornig]

Hi there,

On Tue, May 20, 2014 at 5:29 PM, Michael Ossmann <mike at ossmann.com> wrote:

>
> Please see: https://github.com/mossmann/hackrf/issues/85
>
> This is a firmware enhancement we would like to have.  The best way to
> implement PPS input would probably be by using a timer on the LPC4320.
>

As long as the timer is stable and deterministic and driven by the 1pps by
a gnss module, this would be okay.
And how is it possible to have the received RX stream correlated with the
timer/gnss of the lpc? We have to be sure that both data streams are not
diverging over time. I need to have it fixed somehow so that I can process
a received bit for example, and then looking up the correlating reception
time in the other stream. Or perhaps in the same data stream, as long as
the multiplexing is doing it flaweless.
Implementing this would be a nice idea for our Google Summer of Code
student. If it can be done, I would consider ordering the HackRF One today
and hope it will be there end of June :).

And another one concerning the hardware: What can you tell me about the
deterministic behaviour of the reception hardware. Is there any position in
the link from antenna input to usb output that could produce a big jitter?
For us it is essential to have a high deterministic behaviour.


> I don't think the CPLD would be useful for this.  A timer on the LPC4320
> would run in parallel to the CPU.
>

Okay, as long as it can be related to the rx-stream and it's not diverging.
:)

Thank you so far,


Andreas
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