B&K Precision 2640 - Manual - Manual (Page 57)

57
Frequency Counter
Select the F.counter under Main Menu - function
The input connector for the frequency counter is BNC connector.
When the input level is inputted into the Frequency Counter, the
measured frequency value is displayed in the frequency input window
Input level is same as below.
35 MHz to 2,000 MHz : 150m Vrms
20 MHz to 1,000 MHz : 100m Vrms