Functional system specifications
- 5 inputs, TTL with 50 Ohm termination.
- Time tags apply to rising edges of inputs.
- 1 ns resolution or better.
- Accuracy (of time-tag differences between channels): /- (500 ps
timebase accuracy).
- Timebase accuracy: +/- 4ppm.
- Implementation details: timebase from a local TCXO on FMC card
and needs calibration. The 4ppm accuracy will only be reached
when used on a White Rabbit enabled FMC carrier.
- External inputs need to be protected against +15V pulses with a
pulse width of at least 10us @ 50Hz (with protection diodes if
possible).
- SMC connectors for all inputs.
- Minimum input pulse width: 100 ns. Pulses shorter than 20ns should
be ignored.
- A circular buffer will contain time tags for at least the last 100
input pulses. These time tags will at first be rough UTC (counter
initialized by SW) giving ~ms accuracy. Later, with a WR-enabled
solution, they can be much more accurate. Differences between
channels will not suffer from this accuracy problem because the
offset with respect to UTC will cancel.
Project Status
Date |
Event |
06-12-2010 |
Project start. |