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SC-TDC-1000 S Series Manual
SC-TDC-1000 S Series Manual | Surface Concept GmbH
4.2.4 Device Synchronization Signal IN/OUT
The data acquisition can be synchronized to an external signal for various measurement application linked
to external devices. This device synchronization signal has to be applied as LVTTL signal to the “SYNC IN”
(BNC socket) of the TDC. This functionality is switched on/off within the tdc_gpx3.ini file.
The corresponding entry in the tdc_gpx3.ini file is:
Ext_trigger = X
X is either NO or YES.
The default setting is NO
.
The TDC ignores any external synchronization signals if “Ext_trigger” = NO. In case that “Ext_trigger” = YES
and the “SYNC IN” signal is not provided, the device will not come to operation at all.
The TDC provides always a LVTTL signal on the “SYNC OUT” (BNC socket) after the end of each acquisition,
independent on the setting of “Ext_trigger”.
Note
Do not forget to save the ini file after any changes you make and restart the software. For
further information check the software manual.
4.2.5 Start Frequency Divider (sub-R 85 and E8 only)
The maximum start frequency for the SC-TDC-1000 S devices is restricted to 7MHz. To cope with larger
start frequencies the SC-TDC-1000 S devices are equipped with an internal start frequency divider for
external start frequencies of up to 150MHz (this mode only works when using the external start input).
Herewith the frequency divider can operate with different dividing factors, which can be set within the
software, to always guarantee a start frequency of below 7MHz.
The frequency divider is switched on/off within the tdc_gpx3.ini file, in which also the dividing factors are
set.
The corresponding entry in the tdc_gpx3.ini file is:
Start_Divider = X
X is an integer value and must be one of the following values: 0, 2, 4, 8, 16 or 32. The value 1 is not allowed.
The default setting is 0
X = 0 switches off the start divider and leads to normal operation without dividing the start frequency.
The time histogram will appear X times in series, when using a dividing factor of X. This is due to the fact
that only each 1st start pulse out of a sequence of X start pulses will be accepted as start signal, while all
stop signals are detected. This leads to the multiple time histograms that appear sequentially in time. The
multiple histograms can be resorted to one single time histogram by a MODULO-operation during data
analysis.
