Anfatec AMU5.0-LIA, Руководство пользователя

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F
REQUENCY
If written in black letters, this is the actual reference frequency which is used at the reference output
and as reference frequency for the signal evaluation of the input. Click with the right mouse button
to switch from external to internal reference. In case of internal reference, the numbers are written in
grey.
A
MPLITUDE
This is the amplitude of reference output.
P
HASE
Allows to give a phase offset between the reference output and the input. In the schematic in Fig. 4,
this phase is equal to the LockIn input parameter “Phase
γ
”.
H
ARMONIC
Selects, which harmonic of the reference frequency is evaluated. The possible values range from 1
to 9. When selecting higher harmonics, take care, that, due to lowpass filtering, the maximum input
frequency the LockIn cannot be higher than 2 MHz.
S
WEEP
F
REQUENCY
This window serves the acquisition of frequency dependent spectra of any of the LockIn input
channels. The frequency sweep uses the internal reference. When the PLL is enabled for normal
operation, it will be disabled during frequency sweep.
The number of data points, parameters for the visualisation as well as for the saving and copying the
acquired data can be changed in the
option window .
W
INDOW DESCRIPTION
“Delay” : is the time delay between each acquired data point. During spectrum acquisition, the
frequency is set to the next value. Then, the system waits “Delay” and takes one single value from
the acquired Channel.
As this delay has to be related to the time constant of the LockIn, the options in the drop down list
for the delay are given in multiples of
τ
. Thus, independently on the time constant
τ
given in the
main window , the time constant for the acquisition of the spectrum is always correct.
“from” and “to” define the values of the start frequency and the stop frequency. For the spectrum's
acquisition, one chooses the wanted frequency range, and presses the “start-button”. If the time
constant was very high, the spectrum might take a while. In order to stop the acquisition, the start-
button can be pressed a second time.
“Channel” is a drop down list of available data channels (X, Y, R, and Phi).
“Range back” - click with the right mouse button in the data screen, and a pop-up menu with list
of four frequency ranges appears. The upper one is a standard range, which can be changed in the
“Option/acquire” part. The next three are, from the bottom to the top, the last three used frequency
ranges.
Manual Anfatec PCI-Lockin Amplifier AMU5.0 – Rev. 1.01 Page 19 (34)