Hitachi U-5100 Instruction Manual page 152

3.2 Automatic Continuous Measurement (6-cell auto mode)
The setting of peak detection sensitivity is employed for judging whether data has increased or
decreased by comparing the data at the present base point and the data after N points, based on
which a peak will be detected. Explanation is given here in the case of peak detection where peak
sensitivity is set at level 1 (data after 6 points to be used for comparison).
When the data after N points is larger than at the present base point, it is taken as a rise.
When smaller, it is taken as a fall. Thus, data at the next base point is compared with that after N
points. This sequence is repeated for rise or fall judgments. (See Fig. 1.) When a rise occurs
N/2 times in succession followed by N/2-times succession of a fall, it is judged that a peak is
detected. Also, when a fall occurs N/2 times in succession followed by N/2-times succession of a
rise, it is judged that a valley is detected. (See Fig. 2.)
Base-point data
Data after N points D6
Rise/fall judgment
Sensitivity setting assigns a concrete number to "N" which represents the number of points after the
base point to be used for peak detection. Table 2 lists the relation between sensitivity level and
data checking interval. At sensitivity level 1, data after 6 points is checked. At sensitivity level 8,
data after 48 points is checked. Therefore, sensitivity level 1 should be selected for detecting
peak/valley in a sharp spectrum, and sensitivity level 8 for detecting peak/valley in a spectrum
having a moderate curve.
Table 2 Sensitivity Level and Data Checking Interval
Explanation 3-9 Peak Detection Sensitivity
D5
D4
D3
D2
D1
D0
Rise
Rise
Rise
N points
Fig. 1 Schematic Diagram of Peak
Table 1 Rule on Rise or Fall Judgment
D0 D1
D7
Rise Rise
Sensitivity Level
1
2
4
8
D6
D7
D8
D9
D10
Fall
Fall
Fall
D2 D3 D4
D8 D9 D10
Rise Fall Fall
Interval (N points)
6 points
12 points
24 points
48 points
3 - 88
D11
D5
D11
Fall