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Trace Math
Press <1 Shot/Loop> to select 1 Shot.
13. Connect the Sine Out to the A input using a
BNC cable.
Wait until the value of X reaches 1 V.
14. Press [DISPLAY/SCALE]
Press <Format> to select Single.
Press the <± Range> softkey. This is the fifth
softkey from the top.
Press [1] [ENTER]
Press the <± Range> softkey again to high-
light the center (@) value.
Press [0] [ENTER]
15. Press [START/CONT] and after about 10 sec-
onds, remove the cable from the A input.
16. Press [MATH]
Press <Fit>
Press <Fit Type> to select Exp.
Press [CURSOR]
Use the knob to position the cursor at the point
where the signal starts to decay.
Stop data acquisition after the scan is complete.
The input impedance of the lock-in is 10 MΩ. The
Sine Out has an output impedance of 50Ω. Since
the Sine Output amplitude is specified into a high
impedance load, the output impedance does not
affect the amplitude.
The sine amplitude is 1.000 Vrms and the
sensitivity is 1 V(rms). Since the phase shift of the
sine output is very close to zero, the upper display
(X) should read close to 1.000 V and the lower dis-
play (Y) should read close to 0.000 V.
Show the Display and Scale menu.
Display the full screen chart again.
Set the chart scale.
Set the range to ±1 V.
Set the chart center.
Set the chart center to zero.
Start the scan. When the cable is removed, the
value of X should decrease to zero over the next
15 seconds or so.
Wait until the scan finishes. When the scan is fin-
ished, the DONE indictor at the bottom left of the
screen will switch on.
The graph should be an exponential decay starting
when the cable was removed from the input. Let's
fit a curve to this data.
Display the Math menu.
Choose the Fit menu.
Choose exponential fit.
Activate the cursor.
Use the cursor to determine the graph region over
which the curve fit will be calculated.