07-14-2010 01:54 PM
Hello all,
Was just curious about why I have a coercion dot on my FFT Power Spectrum when suppling it a waveform? I thought (and the detailed help agrees with me) that a waveform was the required type of input. Maybe there is more going on here than I realize but clearly I don't see it.
As a sidenote I'm going this because I'm replacing an express VI in an application I was handed to finish up and the express power spectrum VI seems to give results that are off by the square of the input function. Ok so that sentence makes little sense, so what I mean is when I hook a function generator up to my DAQ board and supply a sine wave of a known frequency the express power spectrum VI gives 16Hz instead of 4Hz, or 2500 instead of 50. The normal power spectrum VI works fine. Don't like Express VI's anyways but just curious.
Thanks in advance!
Solved! Go to Solution.
07-14-2010 02:00 PM - edited 07-14-2010 02:00 PM
Code?
This shows no coercion dot:
07-14-2010 02:05 PM
Here's the relevant part of the code. And yeah its messy...still testing it out at the moment!
07-14-2010 02:11 PM
Are you certain that t0 is in the correct format?
07-14-2010 02:13 PM
Well its the inverse of my sampling rate.
07-14-2010 02:14 PM
That would be dt.
07-14-2010 02:16 PM
Yeah it would...please excuse my inability to read! The t0 is just coming in from a "Get Time/Date in Seconds"
07-14-2010 02:21 PM
Is the Y array DBL? SGL or EXT would produce a coercion dot.
Lynn
07-14-2010 02:24 PM - edited 07-14-2010 02:24 PM
Are the array and dt the same precision? i.e. dbl?
Lynn beat me to it.
07-14-2010 02:24 PM
Good call! It was a single. I put in a convert to dbl and coercion dot is gone. Thanks a lot everybody!