4-36 Service Guide E8364-90026
Troubleshooting PNA Series Microwave Network Analyzers
Measurement System Troubleshooting E8362B, E8363B, E8364B
Figure 4-10 Serial Bus Test Dialog Box
Node Descriptions, A12 Source 20
Node 111 ALC integrator Node 111 senses the output of the ALC integrator. The 
output of the ALC integrator is the combined voltage output of all 
compensation circuits in the ALC. The voltage level varies with frequency 
and output power.
Node 112 Level Output Node 112 senses the output of the detector log amp in the 
ALC. 
Node 113 Detector Level Node 113 senses the power level of the internal detector 
signal from the output of the A12 source 20.
Node 114 −1V/GHz Compensation Node 114 senses the inverse of the −1V/GHz 
signal that comes from the A11 phase lock board. The −1V/GHz compensates 
for first-order power changes of the YIG oscillator with respect to frequency.
Node 115 Temperature Compensation Node 115 senses the output of thermistor 
circuity that compensates for changes in operating temperature of the YIG 
oscillator.
Node 116 Power DAC Node 116 senses the output voltage of the power DAC. This 
output is summed with other compensation signals to control the source 
output level. The power DAC has the most influence of the compensation 
signals.
Node 117 Power Amplifier Compensation Node 117 senses the voltage 
compensation for the source output power amplifiers. This compensation is 
set for each source band.
Node 118 Permanent Magnet YIG Oscillator (PMYO) DAC Node 118 senses the 
output voltage of the DAC that sets the frequency of the 3.8 GHz PMYO.