User`s guide

MAC III Mode 11
Agilent 5500 SPM User’s Guide 173
The following parameters are available in the ACAFM Controls
window:
Amplitude Displays the amplitude, in volts, of cantilever
oscillation.
Drive (%) The amplitude of the lock-in drive signal, stated as
a percentage (0-100 %) of the maximum available
10 V.
Frequency (kHz) Displays the frequency of the lock-in signal. From
the AC Mode Tune window you can sweep the
frequency of Lock-in 1 to determine the resonance
frequency of the cantilever.
Gain Multiplies the output of the lock-in by the selected
factor. Use a larger multiplier to improve the
signal-to-noise ratio for a small signal. Ensure that
the gain will not result in an amplitude exceeding
10 V, beyond which the signal will be clipped. The
default value is x1 (the amplitude times 1).
Drive Mechanism The mechanism (AAC, MAC or Top MAC) used
on the microscope.
Zero Phase Sets the phase at the current frequency to zero,
making it easier to interpret phase changes from
the current value.
Q Control On By applying a phase-shifted version of the
cantilever drive signal on top of the drive signal, Q
control can either increase or decrease the
effective quality factor of the system. Select this
box to enable the Q Control feedback loop. By
default, Q Control is turned Off.
Drive (%) Sets the amplitude of the Q Control phase-shifted
signal, stated as a percentage (0-100 %) of the
maximum available.
Optimize Sets the optimal Q-Control Phase Shift and Drive.
When you initiate the approach, the Amplitude 1 and Phase 1 signals
will be routed through the Deflection and Friction channels,
respectively, to the main controller. During the laser and detector