５
MEASUREMENT OPERATION
5-224
TMPM5200-2
urce
w. The source signal is the one used for measurement after feedback. Settings
ere do not influence the feedback operation.
Display So
Specify detailed parameters to each source signal for measurement in the Display Source
tab windo
h
•
Fi
st from 10 Hz to 50 kHz in the Filter/Hz
the
conv
When the image includes a lot of high-frequency components such as noise, and
you cannot remove them by using Feedback Filter, Lo
rent/Reference, then select a lower frequency. Remember that this filter is used just
as an auxiliary means. This filter is not provided to the exterior display sources
AUX
•
Gain
Set a gain to each source signal, selecting it from the six steps 1 to 32. Gain is
useful for very low contrast images such as the atomic image. If you specify a high
gain for observing a wide area or an uneven-surface specimen, the image contrast
may become saturated. Usually, observe images using a low gain; but if you cannot
obtain enough contrast, use a high gain.
If the Enable Pre-Scan check box is checked, the system will automatically
obtain the optimum gain from the results of Pre-Scan.
When you change the gain during measurement, the signal might become
saturated unless you readjust the offset.
•
Offset/V
Specify the offset voltage to each source si
effect on
en you have
chan
lter/Hz
Each input source has a filter circuit. You can specify the filter selecting its cutoff
equency
fr
from the eight steps that exi
selection box. hese filters, hav
T
ing nothing to do with the feedback, are added to
measurement signal after feedback as a low-pass filter before performing A/D
ersion.
op Gain and Cur-
1, AUX2 and AUX3. Usually, select 50 kHz.
gnal in this input box. Offset/V is in
ly when the Autoset check box is not checked. Use this wh
ged the gain during measurement and the signal has become saturated.
