５
MEASUREMENT OPERATION
5-238
TMPM5200-2
ontrol
etection circuit
e shift of frequency based upon the frequency specified here.
•
Phase Shifter
The Phase Shifter slider enables you to control the phase, which can be set in
al (amplitude of
he frequency is
.
n
•
Output Amp/V
n t
ange
e (frequency detection range) of the frequency detec-
ecomes
. If the
Range width
７６
Hz
Range2:
Range width
７６
Hz
Range3:
Range width 305 Hz
Range4:
Range width 610 Hz
•
Loop Gain
Specify the loop gain in the PLL movement. If the dynamic gain is the same,
the smaller loop gain set in the Loop Gain selection box will improve the re-
solving power for detecting the frequency. Usually, set the Loop Gain as fol-
lows:
Dynamic range Range1:
Recommended Loop Gain 30
Dynamic range Range2:
Recommended Loop Gain 20
Dynamic range Range3:
Recommended Loop Gain 10
Dynamic range Range4:
Recommended Loop Gain 5
•
PLL C
Frequency detection in the FM mode is executed in the frequency-d
of AFM AMP using PLL (Phase Locked Loop). Specify parameters for frequency
detection.
•
Locked Center Frequency/kHz
Specify the center frequency for frequency detection. The frequency detection
circuit detects th
Usually, enter the value near to that of the resonance frequency (peak fre-
quency) of the cantilever.
the range of
±
130°. Set the Phase Shifter so that the RMS sign
condition that t
the cantilever) becomes a maximum under the
equency of the cantilever
set to the resonance fr
•
Polarity Reverse
Phase Shifter circuit cannot uniformly rotate the phase by 360° i
Usually, the
its characteristics but always has discontinuous point somewhere in control.
The Phase Shifter installed on the AFM amplifier resolved this problem by re-
larity of phase detection. If this check box is checked, the phase
versing the po
rotates by 180° from the present angle. Since the operation is performed by the
hardware, the preset value of phase rotation on the software does not change at
all.
Specify the voltage amplitude of the oscillation signal to the cantilever. Oscil-
lation voltage i he FM mode is much smaller than that in the AC mode.
•
Dynamic R
Specify the dynamic rang
tion circuit. If the dynamic range is small, the detection sensitivity b
better. However, the detectable frequency amplitude becomes smaller
ic range is large, the result will be reversed. If you select Range 1 in the
dynam
Dynamic Range selection box, the dynamic range will be the smallest. If you
select Range 4 in the Dynamic Range selection box, the dynamic range will be
the largest.
Range1:
