PRELIMINARY
Document type:
Title:
Revision date:
Revision:
User's Manual (MUT)
Mod. V1729 4 Channel 12 Bit Sampling ADC
22/06/2005
3
NPO:
Filename:
Number of pages:
Page:
00109/04:V1729.MUTx/03 V1729_REV3.DOC
38
14
Fig. 2.7: unfolding of the circular memory
This information associated with the
MINVER
and
MAXVER
calibration constants (see
3.3.1 permits determination of the position of the Trigger and therefore realignment of the
data with a precision in the region of 50ps RMS. This realignment is unnecessary if the
user simply desires to study the signal shape and in this case, the curve acquired will
present a jitter of a period of Fp. The information of the 4 verniers from the same board
being redundant in order to realize the temporal adjustement, it is therefore possible :
- to use solely the vernier from the channel 0.
- to use the vernier i for the channel i.
- to calculate the mean of the 4 verniers in order to refine the time precision.
The following formula permits determination of the time of each point of the reordered
table, with by convention a time origin (Time = 0) at the arrival of the Trigger.
(3)
Time[NEWi] = DT0 + {NEWi - 20 *[128 - PO Correc_Ver]} * dT
With:
(4) Correc_Ver = (VERNIER - MINVER) / (MAXVER - MINVER)
Writing
direction
Last cell
=cell n
trigger
cell
n+1
cell
n+2
cell
127
cell 0
cell 1
cell i
cell n -1
cell …
cell …
1.1.1.1.1.1.1.1
P
1.1.1.1.1.1.1.2
REORDERED
ARRAY
CIRCULAR
BUFFER
S
T
A
R
T
T
R
I
G
E
N
D
cell …
cell …
