Reference frequency input port of PLL chip

The reference input exhibits very high impedance and should work well with squarewave CMOS signals. Is it mandatory to put an additional resistor together with DC blocking caps to make it work in a 50-ohm environment.

Is this also required for sinewave reference input.

The right capacitor is probably needed for preventing DC-voltage from the PLL IC input to reach the 49.9 ohm resistor.

For sinewave input the left blocking capacitor may be omitted. But only if the TCXO output does not contain a DC-voltage and can be connected direcly to a resistor load.

Which PLL chip are you using?

I am using peregrine integer-n pll chip 9704.