HP 8901B Service Manual page 228

Model 8901B
Service
Figure 80-1.
Lo
Configuration: DAC to HF VCO
Figure
80-2.
LO Configuration: DAC to LF VCXO
Next, the LO is configured as a phase-lock-loop as shown in Figure 8D-2. The DAC is now connected
to the tune input of a highly stable, Low-Frequency, Voltage-Controlled, Crystal Oscillator (LF VCXO).
8D-6 Service Sheet BD1