Henk provides the following commentary for the spreadsheet:
The signals from the reference oscillator are in light green, the input connectors are in dark green, and the output connectors of the units involved are in pink.
It all starts with PLL1 (the kHz steps), and continues with PLL2, the MHz steps. The outputs of both go to PLL4, the Wide Oscillator Lock.
The Wide Oscillator Lock output controls the sweep oscillator, which also contains a mixer which mixes the signals down to 0-520Mhz. From there it goes to the output amplifier.. this is the main loop.
PLL3 and 5 are for additional functions such as FM modulation and the Vernier Tuning on the front. They change the frequency of the Narrow Oscillator (VCO) which in turn also controls the Sweep Oscillator.