I have a BK Precission 1856D Frequency Counter.
It has a BNC input connector for a 10MHz external reference frequency input.
The input is terminated with 600 Ohms.
From the 1856D Manual
EXT. STD. IN: 10 MHz (External Standard Frequency Input)
LEVEL: 1.5Vrms to 5Vrms
IMPEDANCE: Approx. 600Ω
I want to connect an external reference oscillator using a coax cable that has a mating BNC connector.
The coax cables I've found have either 50 Ohm or 75 Ohm characteristic impedance.
1) Why did they choose a 600 Ohm internal termination for the BNC?
2) How best to drive this input?
I've considered using a BNC "T" with a 50 Ohm BNC Terminator at the input connector and using a standard 50 Ohm cable.
Is there a better way?