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Wavevision 5 ASCII import

Jeff Bateman
Prodigy 70 points


Wavevision 5: using ASCII data import for a 16-bit ADC.

I've tried both signed decimal (2's complement) & unsigned decimal (offset binary) formats. In both cases, Wavevision changes the sample width from 16 bits to 17 bits. The Data Format, Override option doesn't help (actually it doesn't seem to do anything).

The effect is that the time domain amplitude readout is 0 to 131071, instead of 0 to 65535, or -32768 to 32767.

I'm not sure what it is doing to the FFT readout.

Any advice on what to do so that the sample width stays at 16 bits?

Thanks!

  • 0
    TI__Expert 4340 points

    Jeff,

    Wavevision 5's import feature has a bug that prevents reliable import of data files that were created using the 'export to ASCII' function which appears related to the format of the numbers in the data file and results in an incorrect assignment of the resolution. Data files that contain unsigned- or signed-integer data do not always import correctly. 

    It is unfortunate that TI is no longer fixing bugs in this software, but there are some workarounds that seem to work consistently for me regarding the import of unsigned integer data in the range 0 to 2^(N-1):

    Workaround 1: When importing data, select the data file, the data column, select the resolution and enter the sampling rate. Then switch over to the file settings tab and override the data type to be floating (be sure to press the override button) and then press import. 

    Workaround 2: Post-process your data to convert that data so that it looks like a floating point numbers. Integers should be appended with '.0'

    Workaround 3: Instead of using the 'Export to ASCII' to save data, always use 'Save current channel to a file' function. This saves the data file in a slightly different way. Most importantly, samples are formatted as floating point numbers which import without error. When the data file is generated in this manner, it can then be brought back into WV5 using with the 'Import ASCII Data' or 'Load channel data from file' (available on the Channels Tab on the left side of the screen).

    At thsi time, I do not have a solution for importing signed data (where the center point is 0).

    Please give these work-arounds a try with your data and let me know if this works for you.

    Thanks, Josh

  • 0 in reply to Joshua Carnes
    Prodigy 70 points

    Josh,

    Thanks VERY much!

    Workaround 1 and 2 both worked, and it's easy for me to convert data files to offset binary floating point format using Python. Problem solved!

    Cheers - Jeff