Owner manual

5.6.3 SUBSTANCES
746 VA Trace Analyzer / 747 VA Stand
5-133
Parameter Range; Default value / Meaning
t.threshold 0.100...9.99 ms; 4.0 ms
Time limit value
Minimum time limit (peak area) for the assignment of a peak to a
substance (for measurement mode PSAMODE). With the aid of the 1
st
derivative of the peak curve, the difference ∆
minmax
is multiplied by the
empirical factor f
MM
valid for the PSAMODE to determine the esti-
mated peak area approx.peak. This estimated value must be larger
than t.threshold for the substance to be recognized (see also
section 6.6).
With non-gaussian shaped peaks, the peak height approx.
peak estimated from the derivative can differ greatly from
the actual peak height t.peak. It may be necessary to
modify t.threshold for the results to be displayed or
suppressed in the desired manner.
aU.width
U.width min
U.width max
U.verify ± U.tol
aU.peak
approx.peak =
aU.max aU.min
d(t/U)/dU
U
U
t/U
The substance recognition is
based on the recognition
parameters specified for the
individual substances. The
following conditions must be
met for a detected peak to
be assigned to a substance:
1. aU.peak =
U.verify ±± U.tol
2. aU.width > U.width min
aU.width < U.width max
3. approx.peak >
t.threshold
∆
minmax
× f
MM
∆
minmax
estimated
gaussian
peak