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Title:
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User's Manual (MUT)
Mod. DT5740 32 Channel 12bit - 65MS/s Digitizer
04/05/2016
12
NPO:
Filename:
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00100/09:5740x.MUTx/12
DT5740_REV12.DOC
50
26
GROUP MASK (Bit[7:0] of the 2
nd
header word) = it is the mask of the groups participating in
the event (e.g. GR1 and GR3 participating → Group Mask = 0xA). This information must be
used by the software to acknowledge which group the samples are coming from (the first
event contains the samples from the group with the lowest number);
EVENT COUNTER (Bit[23:0] of
3
rd
header word) = it is the trigger counter; it can count either
accepted triggers only, or all triggers.
TRIGGER TIME TAG (Bit[31:0] of 4th header word) = It is the 31-bit Trigger Time Tag
information (31-bit counter and 32
nd
bit as roll over flag), which is the trigger time reference.
If the ETTT option is enabled, then this field becomes the 32 less significant bits of the
extended 48-bit trigger time tag information in addition to the 16 bits (MSB) of the TRG
OPTIONS field (2
nd
event word). Note that, in the ETTT case, the roll over flag is no more
provided. The trigger time tag is reset either as the acquisition starts or via front panel signal
on GPI connector, and increments every ½ ADC clock cycles. So, TTT resolution is 16 ns and
ranges up to 17 s (i.e. 8 ns*(2³¹-1)), which can be extended to 625 h (i.e. 8 ns*(248-1)) by the
Extended Trigger Time Tag option.
3.3.4.2
Data
Data are the stored samples. Data from masked channels are not read.
