To Adjust The High-Frequency Pulse Response - HP 54520 Series Service Manual

CAUTION
Chapter 4: Calibrating and Adjusting
To adjust the high-frequency pulse response
To adjust the high-frequency pulse response
This procedure optimizes the high-frequency pulse response, so the instrument will meet the
bandwidth specification.
When to use this procedure
This procedure should not be performed as a part of routine maintenance. Typically, a
high-frequency pulse adjustment needs ta be done only when a channel fails the bandwidth
performance test or when an attenuator, acquisition hybrid, or the main assembly has been
changed (new combination of attenuators, hybrids, and PC board). Only adjust the channels
involved with the failure or repair.
Equipment Required
Equipment Critical Specifications Recommended
Madel/Part
Pulse Generator tr <175 ps Picosecond Pulse Labs
1110B Driver/1107A or
1107B Head
Extender Cable No substitute 54542-61609
Adapter SMA 3.5 (m) to BNC (m) HP 1250-1787
Set up the equipment
Use this procedure to gain access to the adjustments. It is necessary to raise the supply to get
clearance above the main assembly. If necessary, refer to the procedures in chapter 6,
"Replacing Assemblies."
Remove the power cord and the cover.
2 Remove the two screws that secure the disk drive to the top of the power supply and
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set. the disk drive to the side while you remove the supply.
Disconnect the three cables on the left side of the power supply.
Remove the two locking pins and slide the power supply out of the instrument.
Disconnect the standard power supply cable from the main assembly and connect
the extender cable.
Make sure that the instrument fan or an external fan is used to circulate.the air through the
power supply. If the supply gets too warm, the thermal cut-out in the supply will shut the
supply off.
Suspend the supply in the instrument cabinet.
The power supply has two flanges that normally support it in the grooves in the cabinet If you
place the supply with the flanges supported by the top of the cabinet (front and rear), it will
hang so it is partially in the airflow from the fan, you can connect the line filter cable to the
supply, and you can still get clearance to the adjustments on the main assembly
Connect the Extender Cable to the power supply.
Reconnect the line filter cable to the power supply.
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