Wiener AVM16, Руководство пользователя

Страница: 22 / 33

22
number of clock units after the last maximum
(start time point) from where a new pulse (even
a pile up) can be detected.
Maxima and minima computed according to parametrization are found in
•
Label 0x32: minimum time
•
Label 0x33: minimum level
•
Label 0x34: maximum time
•
Label 0x35: maximum level, bit 19 is used to indicate overflow.
Pulse arrival time (zero crossing) and derivative are given as
•
Label 0x36: zero crossing, bit 15:14 are used for
∆
X:
•
00 => ∆ X =1 bin
•
01 => ∆ X =2 bins
•
10 => ∆ X =4 bins
•
bit 13 determines the sign. Negative means before the trigger (t = 0).
For each peak, the first derivative is computed in the middle point between maximum and baseline
(for pile up peaks the last minimum is used instead of the baseline) using 1, 2 and 4 bins. The
choosen value corresponds to the biggest
∆ X for which
¼ h < ∆ Y < ¾ h
where h is the peak heigth. From the first derivative, the zero crossing time point is extrapolated.
•
Label 0x37 indicates the beginning of a block of 4 values with data describing
the integral window. This block is transmitted at the beginning of the features
extraction data and contains the following information:
•
1st value 0x37: instant mean line level (updated continuously as long as no
trigger is fired).
This value is identical to 0x31
•
2nd value 0x37: mean value of the 4 samples before the integral window
•
3rd value 0x20: integral on the whole user parametrized integral window (IW)
•
4th value 0x37: mean value of the 4 samples following the integral window