Owner manual

6 Data processing and evaluation
746 VA Trace Analyzer / 747 VA Stand
6-18
6.7.5 Baselines for PSA curves
With curves recorded with the measurement mode PSAMODE, there is no possibility
to select a method to calculate the baseline, the corresponding baseline parame-
ters are missing on the dialog page "SUBSTANCES".
The baseline is calculated automatically with the predetermined parameters Type =
linear and Scope = whole. The baseline is determined by the tangent method
where, starting from the automatically determined peak base points dU.front and
dU.rear, an iterative search is made within a fixed range for identical slopes. The
range of the tangent search is ca. 20 mV outward and inward up to 1 point before
the peak maximum.
If two points with identical slopes are found, the two points of tangency are con-
nected with each other to give the linear baseline. If no common slope is found, the
linear baseline is drawn directly between the two base points.
The two base points dU.front
and dU.rear are only displayed
and can not be changed. On the
other hand, it is possible to dis-
play the subtracted curve
subtracted to check the
evaluation (see section 6.7.4).
PSA
dU.front dU.rear
Point of tangency
(rear)
Subtracted
curve
Base point
(front)
Range for
tangent search
Range for
tangent search
Base point
(rear)
Point of tangency
(front)