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SensL © 2011
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USER MANUAL
HRM-TDC
SensL © 2011
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> Hrm-tdc System Description > Histogram – Single-stop (“tcspc” Mode)
HISTOGRAM – SINGLE-STOP (“TCSPC” MODE)
Figure 5
Histogram modes use consecutive memory locations to store counts that represent successive timing values (Fig.5a).
These memory locations or “time bins” are incremented based on the result of a time measurement between a
START and the first STOP received. In this single-stop mode, this is repeated to build up a histogram in memory
showing the distribution of first events (STOPs) following a START input. This process is illustrated in Fig.5b and
Fig.5c, and an example GUI data plot is shown in Fig.5d. Data is saved to the PC in .CSV format. This mode is also
referred to as ‘
TCSPC
’ in the SIE, due to its application in Time Correlated Single Photon Counting.
Note:
In this mode the START of each channel will be the event and the STOP will be a delayed version of the
LASER clock. On receipt of an event the timing value will be read and then the timing module will immediately be
reset. The reset will clear the channel ready for the next event. Each time-stamp from the timing module will be used
as an address to increment a memory location (time-bin). The resolution of the bins and the position of the curve in
memory will be defined by the highly flexible Address Routing Module. The timing value, address counter and I/O
bits can all be routed to the memory address lines. This flexibility allows many options, from a simple single curve to
multiple curves defined by the address counter and external control from the I/O port.
Min Time Bin Size:
27ps
Max Time Bin Size:
143
m
s
Max No. Time Bins:
4,194,304
Time Bin Depth:
65,536 or 4,294,967,296
Max Count Rate:
4.5Mcps
Max Image Size:
2048 x 4096
Fig.1c
a)
b)
c)
d)