THORLABS SA201-EC, Operating Manual

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Spectrum Analyzer Controller Chapter 5: Operation
Rev H, November 30, 2021 Page 11
Chapter 5 Operation
5.1. PD Blanking Circuit
The detector amplifier includes a blanking circuit, which blocks any photodetector
response during the falling edge of the saw tooth waveform. This is very useful
when triggering on the photodiode spectral response, because unwanted signals
while the cavity resets will be removed. The blanking is not available when using
the triangle waveform, since it is useful to see the rising and falling response
overlapped during system alignment. This feature may be disabled as described
below:
IMPORTANT
Before continuing, disconnect the scanning head or any piezo device from the
SA201 output. Disconnect the power cord.
Do not open the unit if the power cord is connected.
1. Remove the two screws securing the enclosure cover with a Phillips head
screwdriver. The screws are located on the bottom side, rear corners of
the unit. Do not lose the screws.
2. Carefully remove the cover by sliding toward the rear of the unit.
3. Locate the JP3 header. It is positioned in front of the heat sink and will
have a shorting jumper on pin 1.
Figure 5 Shorting Cap and Jumper 3
Jumper 3
Blue shorting
cap over pin 1