[time-nuts] GPS for Spirent Smartbits

Eduardo Jacob edu at kender.es
Mon Feb 12 17:49:49 EST 2007


Hello

After putting the question in TAPR list about GPS, I have been 
suggested to put here.

We (at our university research group) use Spirent Smartbits 
Hardware... (http://www.spirentcom.com/documents/1374.pdf) They are 
network traffic generator. They have ports separate ports that can be 
configured to send and receive traffic and you can develop 
applications to program it to suit your needs.

If you use only a chasis, you can measure propagation delays or 
jitter. If you have an Internet access you can get a time reference 
with NTP and even do timed captures. If you use two chasis 
(transmiting from one to a wireless system and receiving on the other 
chasis far from the previous one) and you don't have Internet access 
you can't get a good timing measures. An option is to use GPS 
systems. Spirent does offer an solution, but the information on the 
is so loose it's difficult to know how difficult is to adapt an 
external source.

We  would like to get 2 GPS timing systems in order to test influence 
of handovers in Wimax on moving vehicles. We have already spend much 
with the equipment and we would like to study if it is possible to 
get a solution at a faction of the cost of "official Smartbit 
solution" They use 58503 (HP?) or NanoSync hardware but I don't get 
information about the interface levels (ttl or RS-232) or needed commands...

Has anybody experience with this hardware or advices? It seems that 
the equipment need more that the 1PPS and NMEA string

Best regards

Eduardo/EA2BAJ

PD: I hope it's no so much OT.




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