Failure in look-up table / failure in my matlab

Hello,

i have a question about the look-up table function "fixpt_interp1" in matlab. I tried to run the code which is offered in the help section. (See attached m-file). I get no errors but:

By my opinion, the code itself is fine, but it is working wrong in my computer. I get the wrong results (see attached figure). By wrong i mean i expected a sine-output and not the "ramps" i get.

So my exactly question is: What is wrong with my matlab installation?

I use win7 64bit with matlab 2013b (also 64bit). I tried the same code with the same results with matlab 2012b. I even deleted java and all matlab version and reinstalled (java and matlab) with the same result.

regards Benedikt

Answer 1

[Simon]

Hi!

The help uses sfix(8) instead of ufix(8) and another scaling: fixpt_interp1

[Benedikt]

I used the code i got from the "help fixpt_interp1" command. But indeed, if i use the code from the doc it's working. Can maybe someone explain the scaling effects? Do others also geht that "failure" with the help fixpt_interp1 code?

[Simon]

Sorry, I have no Simulink, I just noticed the differences between your code and the online help. Maybe the help shipped with your version is wrong and it was fixed in the online version ...

[Benedikt]

Anyway, you solved my problem, thanks for helping and answering my question! :)