Re: [Discuss-gnuradio] AUTOMATIC START AND STOP FILE RECORDING

[Marcus Müller]

Hi Ernest,

to be honest, yes, you probably could do that post-processing in GNU Radio, but it's offline processing and might be a lot easier to do just e.g. in python with numpy/scipy.

I also plan for NTP. But how do I simultaneously trigger recording with it.

I don't know the HackRF interface very well, but I'd imagine it has some sort of "start" method or just a "first call to gimmesamples()". I'm afraid others will have to jump in here!

Best regards,
Marcus

On 25.08.2016 08:19, Ernest Matey wrote:

Hi All,

Sorry I replied on my other Post ( Nanoseconds). That was not intended.

Thank you for the reply.

To line up the 3 recordings with the timestamps will be a post processing I guess on GNUradio??

I also plan for NTP. But how do I simultaneously trigger recording with it.

Ernest

On Thu, Aug 25, 2016 at 3:10 PM, Marcus Müller <address@hidden> wrote:

Hi Ernest,


On 25.08.2016 07:07, Ernest Matey wrote:
> It is critical for me to start the recording simultaneously and
> synchronized to more than 100ms accuracy between the stations.


100ms is a whole different story than nanoseconds in your other post;
You could probably achieve this 0.1s accuracy by coordinating computer
clocks (NTP, PTP) and then triggering recording with those.

Anyway, since your hardware, as far as I know, doesn't allow for timing
control itself, doing exactly what Kevin recommended sounds clever:
you've inserted PPS signals in your sample stream, so use the very rough
PC-clock-aligned sampling start to give your "roughly aligned" streams,
and extract the PPS information from your recordings later on to fine-align.

Best regards,
Marcus

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