Problem:
I am evaluating the TX810 T/R Switch for a structural health monitoring application. Using the TX810EVM, function generator, and oscilloscope I am actuating and sensing on a single piezo as well as just sensing on another piezo which are both mounted to the same aluminum plate. I am unable to see any of the reflections within the plate at low frequency through the IC.
Test setup:
3 Signal paths
- SigA: A function generator is sending a ~10Vp2p windowed sin wave (narrow frequency) into an input on the evaluation module with a piezo inline. The output is then connected to the O-Scope.
- Function generator -> 2ft cable to BNC T -> (leg 1 of T) 1ft cable to piezo, (leg 2 of T) 1ft to TX810EVM
- SigB: A line is connected from a piezo into the evaluation module which is then connected to another channel on the O-Scope.
- SigC: A line is connected from a piezo directly into the O-Scope (SigC).
All piezos are mounted to the same piece of aluminum. O-Scope is triggered by the function generator.
Results:
- At high frequency (~400kHz windowed sin wave) reflections are seen on all Sig lines, however there is substantial ringing at the beginning of SigA as well as a DC decay. It also appears that the reflections on SigA are attenuated in comparison to SigB.
- I attribute this to reflections in the coax cables in our non-ideal setup.
- At low frequency (~50kHz windowed sin wave) only the actuation signal is seen in SigA. No reflections are seen in SigA or SigB (TX810 path). Reflections are seen in SigC (direct path).
Questions:
Is there a frequency dependence to this component? What is its frequency response?
