Functional Description
ComTec GmbH
4-2
The ADC ports that are allowed to open a coincidence time window are software selectable as
well (ref. chapter 5.1.6). This enables for further data reduction.
In COINCIDENCE mode of operation the corresponding ADC ports accept new data only when a
coincidence time window is open. This is usefull to reduce the system deadtime caused by not
coincident or unwanted ADC events.
The corresponding timing signals as in Fig. 4.1 are available on the auxiliary IOs (ref. chapter
5.1.7).
The transferred concidence data block may also include the real time of the coincidence window
being opened. And, the values of the 100MHz counter 1, 3 and 4 at that time may be included.
And also the TOF sweep counter value which is important in the combined TOF and MPA mode.
4.3. FIFO
Concept
In the MPA4 the START and STOP input channels are not present but the rest is identical as in
the MPA4T which has the additional capability to measure 100ps time events in 5(6) channels.
A multi-stage FIFO concept is used to optimize for the two main difficulties of those data
acquisition systems. On the one hand ultra high burst count rates (here 10 Gevents/s for the TOF
section of the MPA4T) should be acceptable for a period of time as long as possible.
Fig. 4.1: Coincidence processing and timing