New Focus 2001, Руководство пользователя

Страница: 15 / 20

15
Tuning the position and frequency of the
optical output:
1. Use the 8-32 (M4) tapped hole located on the
base of the photoreceiver to mount it on an
adjustment positioning device for alignment of
the optical spot on the photodetector diode locat-
ed on the back side of the unit.
2. Position the mounted photoreceiver in front of
the focusing lens.
A simple 25-mm focal length biconvex singlet
should be adequate for most applications.
3. Turn on the optical beam.
4. Connect the SMA port on the front of the pho-
toreceiver to a voltmeter.
5. Align the detector to the beam until the output
peaks on the voltmeter.
6. Adjust the gain for optimal performance:
Refer to the discussion in Appendix 2: Electrical
Output.
• Set the Low Frequency Adjustment knob to DC.
• Set the Gain knob to the full clockwise position.
• Set the Multiplier to “
×
1”.
• Turn the Gain knob clockwise to increase it until
you measure approximately 2 V on the voltmeter.