Signal And Input Filter - Stanford Research Systems SR124 Operation And Service Manual

1.4 Signal and input filter
1.4 Signal and input filter
SR124 Analog Lock-In Amplifier
4. Connect a BNC cable from the front-panel Ref Out BNC (right-
hand most connector) to the A I input of the Signal Input (left-
hand most connector).
5. Switch on the AC power. Allow the unit to warm up for 1 hour
for full specified performance.
1. Restore defaults:
REFERENCE knob (large right-hand side knob) clockwise un-
til the display shows "deFLt". Press [Recall] a second time to
restore factory defaults.
2. Verify the panel meter shows approximately 20% (positive)
deviation.
3. Turn the SENSITIVITY knob counterclockwise 2 clicks, to se-
lect 100 mV. Verify the meter displays approximately
(positive) deviation.
4. Change the filter to Notch by pressing the [Type] button four
times. The meter should swing to approximately 0% deviation.
5. Turn the Q-factor knob clockwise until Q 100. The meter
should remain near 0% deviation.
6. Press the [Mode] button in the OUTPUT block to switch to AC
Volt mode. Turn the SENSITIVITY knob 1 click counterclock-
wise, to select 50 mV. None of the overload indicators should
be illuminated.
7. Slowly (one click at a time) turn the large INPUT FILTER knob
to minimize the meter display as close to 0 (no deflection) as
possible.
8. Press the INPUT FILTER knob inward once, to illuminate the
f trim indicator.
9. Adust the frequency fine trim by turning INPUT FILTER to
mimimize the meter deflection (minimum is not very sensitive
to f trim).
10. Press the INPUT FILTER inward once more, to illuminate the
depth indicator.
11. Adjust the depth trim by turning INPUT FILTER to mim-
imize the meter deflection (minimum is somewhat sensitive to
depth ).
Press [Recall], and then turn the
1 – 3
100%