I'm trying to figure out what the input impedance of the ADF4113 is.
Looking a figure 15, I'm not sure how to read that.
In my setup input is on RFinA and RFinB if connected to GND via a 100pF capacitor (HF to GND).
If the Bias generator is a current source it is HF open, and then the impedance would be 1k ohms.
But the figure says there is 1.6V at the generator out, which made me think it probably works more as a voltage source, and therefore is HF short, which makes the impedance 500 ohms.
So to figure this out, I tried to measure the impedance, by connecting a generator with a known source resistor, and from that my guess is 1k ohms.
But could some one help me on how get the impedance from the datasheet?