Agilent Technologies E8362B Service Manual page 120

Troubleshooting
Measurement System Troubleshooting
Node Descriptions, A8 Fractional-N Synthesizer Board
+5 Vdc Supply Voltage Node 411 senses the 5 Vdc supply voltage which
Node 411
serves as a measurement reference.
Node 412 1.5 to 3.0 GHz VCO Compensation Node 412 senses the average voltage
output level of the 1.5 to 3.0 GHz VCO.
Node 413 1.5 to 3.0 GHz VCO Tune Voltage Node 413 senses the average voltage
input level of the 1.5 to 3.0 GHz VCO.
Node 414 Heterodyne Band ALC Level Node 414 senses the ALC output voltage
which is used to level the heterodyne circuit output for band 1.
Node 415 2.250 GHz VCO Tune Voltage Node 415 senses the average voltage input
level of the 2.250 GHz VCO.
Node 416 Fundamental and Divide-by-2 Band ALC Level Node 416 senses the
ALC output voltage which is used to level the heterodyne circuit output for
bands 2-25.
Node 417 2.250 GHz VCO Compensation Node 417 senses the average voltage
output level of the 2.250 GHz VCO.
Node 418 ALC Level Adjust Node 418 senses the voltage which is used to set the
offset on the heterodyne band ALC.
Node Descriptions, A16 Test Set Motherboard, MA 20
Node 511 ALC Output Node 511 senses the output of the ALC integrator. The
output of the integrator is the combined voltage output of the compensation
circuits in the ALC.
Node 512 Power DAC Node 512 senses the output voltage of the power DAC. This
output is summed with other compensation signals to control the SOMA 50
output level. The power DAC has the most influence of the compensation
signals.
Node 513 ALC Output Node 513 senses the output of the ALC summing junction.
The output of the ALC summing junction is the combined voltage output of
all compensation circuits in the ALC. The voltage level varies with
frequency and output power.
Node 514 1V/GHz Compensation Node 514 senses the output voltage of the
1V/GHz compensation amplifier for the LO ALC.
Node 515 Slope Compensation Node 515 senses the slope compensation.
−15 V Reference Node 516 senses the −15 Vdc supply voltage which
Node 516
serves as a measurement reference.
+9 V Reference Node 517 senses the +9 Vdc supply voltage which serves
Node 517
as a measurement reference.
+15 V Reference Node 518 senses the +15 Vdc supply voltage which
Node 518
serves as a measurement reference.
4-38
PNA Series Microwave Network Analyzers
E8362B, E8363B, E8364B
Service Guide E8364-90026