51
Verify the Self Noise of the Preamplifier
With the same hardware setup as for the DC voltage measurement, you can measure
the self noise of the preamplifier.
1. On the main window (the software panel), press
Noise
. A new window opens and
the noise measurement starts automatically.
2. You can monitor the current level in the
Total Noise
field and on the two graphs.
The diode indicates whether the current level is within the test limits: green means
it is OK; red means it is outside the limits.
3. When the measurement has stabilized and the “20-20 kHz OK” and “A-Weighted
OK” indicators are green, you can press
Stop
. The window closes and the measure-
ment results are transferred to the main window.
After you record the DC voltage and self-noise, you are ready for the second step in
calibration.
Step 2: Frequency Response
1. Remove the AE0036 short circuit BNC plug from RA0062.
2. Connect a BNC cable to the BNC connector on RA0062.
3. Connect the other end of the BNC cable to the system switchbox connector called
“To Preamp. Input Adapter”.
4. On the main window, click
Frequency Calibration
; a new window opens where you
can start the frequency sweep measurement.
5. Click
Start Measurement
; the “Sweep in Progress” indicator switches on so it is a
bright red light.
6. When the measurement is completed, the indicator switches off so the indicator is
dark red.
The diodes at the top of the window—Freq. OK, Upper Limit OK, and Lower Limit
OK—indicate whether the measured sweep is within the test limits; green indicates
it is within the limits.
7.
When the sweep is finished and the results (the indicators) seem satisfactory), click
Accept
to close the window and transfer the measurement results to the main
window.
If you click
Cancel,
the window closes, but the measurement results are
not
transferred to the main window.
Note
: The
Accept
and
Cancel
buttons are inactive during a sweep. Click
Stop
Measurement
if you want to stop an active sweep.
This completes the frequency response calibration.