Hello,
I am using digital I/O from PXI-7856R on its RDIO connector, which is rated to output 80 MHz maximum in the datasheet. I have tried to output 50 MHz and it looks OK using the SHC68-C68-RDIO2 shielded cable. However, when trying to apply a digital signal to an input from a signal generator (50 Ohm output impedance) the maximum frequency is barely 20 MHz. It looks the 80 MHz rating applies in one direction only, and there is significant capacitive loading in the cable. How can I drive a digital I/O at higher speeds?
Thank you for your help.
Konstantin
Two scope traces attached - 20 MHz square wave from a generator, and the same when applied to a DIO of PXIe-7856R.