[time-nuts] 10MHz LTE-Lite - PPS accuracy?

[Mike Cook]

> Le 10 déc. 2014 à 19:55, Laszlo Hanyecz <laszlo at heliacal.net> a écrit :
> 
> Time-nuts,
> 
> Is it a bad idea to have more than one PPS source on a single machine?  Would this cause additional jitter when trying to compare the timestamps on two sources?  I understand that USB can't deliver a real PPS, but what about using onboard serial ports or a PCI card?
> 

  You would have to test I guess but the potential is there for an issue. It can be circumvented by configuring a 1PPS offset if the receiver allows it , or configuring a reasonable cable delay in the receiver so that the pulses are not simultaneous . The latter possibility exists for the Venus 8 receiver , but I cannot find a command to force a 1PPS offset.

> Thanks,
> Laszlo
> 
> 
> -----Original Message-----
> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Paul
> Sent: Wednesday, December 10, 2014 18:43
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] 10MHz LTE-Lite - PPS accuracy?
> 
> On Wed, Dec 10, 2014 at 12:17 PM, <gigneil at gmail.com> wrote:
> 
>> Quite simply - if you either execute ldattach pps /dev/ttyUSBx, or are 
>> running GPSD (recommended) it will bind the USB appropriately to a 
>> ppsapi instance.
>> 
> 
> I can get a /dev/ppsN but ppstest says time-out.  I saw some hints that the USB DCD
> 
> might depend on the chipset .  I don't like gpsd so I try to avoid it but I might try it.
> 
> Thanks.
> 
>> Do not do it.  You will not approve of the results.
>> 
> 
> I don't intend to use it in production.
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