Hardware: PXIe-5160 2 Ch digitizer, PXIE-1073 chassis, PCIe-8361 bridge card.
Software: Windows 7 SP1 64 bit
I recently switched from a PCI-5154 to a PXIe-5160 to acquire signals from a photomultiplier tube. Specifically, I'm acquiring a luminescence decay obtained after pulsing a laser at 25 Hz (trigger). When I use the 1 MOhm option, I can clearly see the decay (signal) in NiScope. However, when I switch to the 50 Ohm option, the amplitude is completely gone to the point where I only see background noise, even though all the connections are matched at 50 Ohm using terminators (output of PMT and input of digitizer). There is no error message, the signal just turns into background. Both channels have the same problem. I never run into this issue while working at 50 Ohm with the PCI-5154.
Any suggestions would be appreciated. Thanks.
