I'm pleased to see that vttime -m edge+ is doing its job, it
hasn't had a lot of testing.   Also, using -m pulse+ on a
university installation and it is running mostly at less
than 20nS jitter on a 10uS pulse at 96k/sec, albeit on a
posh looking GPS.

> vttime: unreliable PPS interval 47999.959405 - skipped
> vttime: wild PPS pulse interval 32425.608608 - skipped
> vttime: invalid phase slope - skipped

The NMEA messages shouldn't get in the way, vttime only looks
at a narrow window containing the leading PPS edge and the
NMEA will be coming in well after that.

vttime has got better at recognising bad pulses and ignoring
them. it will hold-over quite happily on missing or damaged
GPS pulses.

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Paul Nicholson
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