80 Hz has a period of 0.0125s so peak acceleration / error seems fairly well represented. The shorter period smaller waves look to be about 480 Hz. Could this be from applied dither?
I just heard back from the person who did the test. The dither frequency was 528 Hz but the amplitude was zero.
Looks unlikely that that is the explanation. I did inquire if they were in a position to rerun the test, but they don’t have that dynamometer anymore so we’ll have to look for another way to test out the dither theory.
An excellent observation regarding dither. Pete Bailey has wondered that too. It bothers me that the 480 hz waveform is so non-sinusoidal but that may just be the nature of dither.
I will contact the individual who supplied this data to see what additional info they can supply.
80 Hz has a period of 0.0125s so peak acceleration / error seems fairly well represented. The shorter period smaller waves look to be about 480 Hz. Could this be from applied dither?
I just heard back from the person who did the test. The dither frequency was 528 Hz but the amplitude was zero.
Looks unlikely that that is the explanation. I did inquire if they were in a position to rerun the test, but they don’t have that dynamometer anymore so we’ll have to look for another way to test out the dither theory.
An excellent observation regarding dither. Pete Bailey has wondered that too. It bothers me that the 480 hz waveform is so non-sinusoidal but that may just be the nature of dither.
I will contact the individual who supplied this data to see what additional info they can supply.
Maybe a second harmonic
I am attempting to comment.
This plot looks unusual
I am able to post a comment (David Dudzinski)