[hpsdr] Hpsdr Digest, Vol 67, Issue 31

[Al K0VM]

Latency growth problems are not unique to HPSDR versions of PowerSDR but 
have been an unrecognized problem with the Flex versions of PowerSDR 
also..    It acts like there is 'FiFO' or 'ring' buffer in PowerSDR that 
can get longer as time goes on.   I have seen it grow to 2-3 seconds in 
length.  The latency seems to grow in jumps concurrent with 
overflow/under flows reported by the VAC program although the latency 
growth can be observed even if the VAC program is not involved.

Just my observations... FWIW

AL, K0VM


On 9/29/2011 4:04 PM, hpsdr-request at lists.openhpsdr.org wrote:
> Date: Thu, 29 Sep 2011 11:07:09 +0300
> From: "Riho B., ES7AAZ"<es7aaz at gmail.com>
> To:hpsdr at lists.openhpsdr.org
> Subject: [hpsdr] about latency growth with HPSDR
> Message-ID:<4E84272D.50106 at gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
>
> Hi,
>
> I have a program called Faros which is a beacon monitor.
> Faros gets his time sync from ntp GPS time servers.
> NCDXF network beacons have GPS dicsiplined controller
> which allows path delay calculation and Faros does it.
>
> After 2h running I see 120ms latency growth (linear graph)
> and it's growing on. Which means that radio waves are traveling
> about one  more circle around the world. It can't be so. Restarting
> PowerSDR brings the latency back to its initial state. Exactly the same
> effect with CWSkimmer console. It's almost same vith VAC and with
> analog audio cable.
>
> The question is not even about latency itself or how much it is.
> The question is why's latency growing and how much it does?
>    Is it somewhere in USB connection ?  I'm Ozy user.
>
>
>
> 73,
> Riho, ES7AAZ