Document type:
Title:
Revision date:
Revision:
User's Manual (MUT)
Mod. V1724 8 Channel 14bit - 100MS/s Digitizer
06/11/2007
7
NPO:
Filename:
Number of pages:
Page:
00103/05:V1724x.MUTx/07 V1724_REV7.DOC
63
31
3.5.3.
Local channel auto-trigger
Each channel can generate a local trigger as the digitised signal exceeds the Vth
threshold (ramping up or down, depending on VME settings), and remains under or over
threshold for Nth “quartets” of samples at least (Nth is programmable via VME). The Vth
digital threshold, the edge type, and the minimum number Nth of couples of samples are
programmable via VME register accesses, see § 4.3 and § 4.6; actually local trigger is
delayed of Nth quartets of samples with respect to the input signal.
N.B.: the local trigger signal does not start directly the event acquisition on the relevant
channel; such signal is propagated to the central logic which produces the global trigger,
which is distributed to all channels (see § 3.5.4).
CH0 IN
THRESHOLD
Local Trigger CH0 (Channel
Configuration register <6> =0)
Nth [4samples]
Nth [4samples]
Nth [4samples]
Local Trigger CH0 (Channel
Configuration register <6> =1)
Fig. 3.14: Local trigger generation
3.5.4. Trigger
distribution
The OR of all the enabled trigger sources, after being synchronised with the internal
clock, becomes the global trigger of the board and is fed in parallel to all the channels,
which store an event.
A Trigger Out is also generated on the relevant front panel TRG_OUT connector (NIM or
TTL), and allows to extend the trigger signal to other boards.
For example, in order to start the acquisition on all the channels in the crate, as one of
the channels ramps over threshold, the Local Trigger must be enabled as Trigger Out,
the Trigger Out must then be fed to a Fan Out unit; the obtained signal has to be fed to
the External Trigger Input of all the boards in the crate (including the board which
generated the Trigger Out signal).
3.6. Front
Panel
I/Os
The V1724 is provided with 16 programmable general purpose LVDS I/O signals. Signals
can be programmed via VME (see § 4.24 and § 4.25).
Default configuration is: