PModIA SMA Connector Impedance

[bhayame]

The PModIA has two SMA connectors as the terminals between the impedance to be measured. These connectors apparently have a 50 Ohm impedance. Does this impedance need to be accounted for when taking impedance measurements using the board? I haven't found anything in the documentation mentioning this. Because there's two connectors, would the impedance be doubled to 100 Ohms? I figured when calibrating the board with a test resistor, I would have to add 100 ohms to whatever that resistor value is. 

[JColvin]

Hi @bhayame,

I don't have a Pmod IA on hand and wasn't actually aware that the connectors had a 50 Ohm impedance, though I did confirm that is the case. I believe you would need to add 100 Ohms to the value to get accurate values; it will be a larger impact when calibrating for smaller impedances as discussed on page 30 and 31 of the AD5933 datasheet.

Thanks,
JColvin