In IF access part of pna series network analyzer help, with dsp version 4, the if frequency is 9*(60e6/71)when rf is equal or above 53mhz. In the equation, I guess 60e6 is the sampling frequency of the ADC. What are the 9 and 71 stand for? Someone can help me ,thanks.

This is somewhat proprietary info but the gist of it is this:

As you guessed, 60MHz is the sampling frequency. 71 is just a prime number that is used to avoid spurs of the sampling frequency. I believe the newer spam uses something like 121, but the sampling freq is higher. We can use any multiple of this but we chose 9 to best match our needs.