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TMS320F28027: IQmath Library issue

Cherry Zhou
Mastermind 22235 points

Part Number: TMS320F28027

Hi team,

Here's some issues from the customer may need your help:

Customers are considering using IQmath for processing, and now have the following question:

Three ranges of float data used in a program, as follows:

The first floating point number range is 3122.66~5333.33

The second floating point number range is 3.03 to 6.06

The third floating point number range is -1.999~2.0

The "IQmathLib.h" file has a GLOBAL_Q of 19. The customer would like to know how to deal with the last two types of data at this time to maintain the accuracy of the data results? 

Could you help resolve this case? Thanks.

Best Regards,

Cherry

  • 0
    TI__Mastermind 22235 points

    Hi,

    May I know is there any updates?

    Thanks and Best Regards,

    Cherry

  • 0 in reply to Cherry Zhou
    TI__Expert 5410 points

    Hi,

    The precision (number of fractional bits) and dynamic range (number of integer bits) are inversely proportional. Raising the Q value will increase precision but will result in a lower range of integer bits.  

    IN section 3.2, you can see that GLOBAL_Q = 19 implies a range of [-4096, +4096], with a precision of 0.000001907. SO for the last two cases, Q=19 should work but may not work properly with the first range. Please consult section 3.2 for more information.

    -Shantanu