Appendix A
Specifications
NI PXI-6682 User Manual
A-4
ni.com
Decode Input voltage range ...................1.5 V to 10 V peak-peak mark
(3:1 ratio mark:space)
Input carrier frequency ...........................1 kHz
Caution
Do not connect an IRIG-B AM signal to PFI 0 when the input is configured for
digital operation, as this can result in damage of the digital input circuitry.
IRIG-B DC compatibility .......................IRIG-B 00X
Input characteristics for IRIG-B DC.......same as PFI digital input
characteristics listed above
The following assumptions are made regarding the received IRIG-B signal.
All conditions must be met for the NI PXI-6682 to be able to synchronize
accurately:
•
Seconds begin every minute at 0, increment to 59, and then roll-over
to 0.
•
Minutes begin every hour at 0, increment to 59, and then roll-over to 0.
•
Hours begin every day at 0, increment to 23, and then roll-over to 0.
•
Days begin every year at 1. Days increment to 365 in non-leap years,
or to 366 in leap years, and then roll-over to 1. Leap years must be
supported. Valid values for year are 01–99, inclusive. Years are
assumed to be in the XXI Century. For instance, year
07
represents
2007. If the year is not supplied (sent as
00
), the OS system time is
read and the year is derived from it.
To achieve proper synchronization of the NI PXI-6682 ensure that the
IRIG-B source used conforms to the requirements listed above. Note that
most IRIG-B sources conform to these requirements.
PXI_STAR Trigger Characteristics
PXI_STAR <0..12> to
PXI_STAR <0..12> output skew
at NI PXI-6682 backplane connector .....< 400 ps
1
Asynchronous delays, t
pd
PXI_STAR <0..12> to
PFI <0..2> output.............................11 ns, typical
1
This specification applies to all asynchronous routes from the PFI inputs to the PXI_Star lines.
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