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L o g i c 1 6 U s e r M a n u a l
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Section 1
Introduction
Logic16 is a versatile time tagger and logic correlation unit made especially for analyzing photon detection
signals in multi-photon correlation counting and time-resolved signal analysis.
Logic16 operates in two distinct modes for measurement flexibility: Logic Mode and Time Tagger Mode.
Logic Mode performs on-board coincidence (pattern) counting and can internally process all possible
patterns for the 16 inputs, simultaneously. The patterns to be counted are defined by indicating for each
input whether or not an active signal edge should appear, or if the input should be ignored. In Logic Mode,
the unit can also output TTL pulses triggered by detections of user-selected coincidence patterns. Output
channels are distinct from input channels. Coincidence counting can be performed alongside the use of
the pattern-triggered outputs. Since all time-correlation processing is performed internally, it can be used
even with small, low-power computers.
Time Tagger Mode time tags photon events – in other words, it records the input channel and event time
when signals are detected. In Time Tagger Mode it is possible to perform:
continuous time tagging - time tag each event detected
gated time tagging
- condition time tagging to occur only when signals appear on a specific input
time tag filter
- time tag events only when they appear in groups
- use for time-of-flight
1
measurements with respect to a fast pump signal
2
- use to reduce data file size for long
3
measurements
By employing the time tag filter it is possible for users to measure with sustained
4
data rates up to 190
MHz. However, keep in mind that time tags can be processed on-board Logic16 faster than they can be
sent across the USB interface to the host PC. The time Tag Filter is thus useful for high rate signals when
only select events are of interest.
1
Or “time-of-arrival” (TOA)
2
For example, a 76 MHz Ti-Sapphire laser
3
For example, on the order of days
4
In contrast to burst
