The following two lines have different behavior depending on installed toolboxes:
d = fdesign.highpass('N,F3db',3,1,1000);
Normally, I have BOTH DSP System and Signal Processing toolboxes installed. When I run these lines with both toolboxes installed I get the following error:
Error using fdesign.abstracttype/superdesign (line 90)
For symmetric FIR filters, only even orders are allowed.
Now, if I uninstall DSP System toolbox this pair of lines runs as I expect, and makes a 1Hz highpass filter through which I can run my data in lines following the fdesign/design pair of statements. I presume this means that fdesign/design are available in both toolboxes but for some reason only the one in the Signal Processing toolbox works as I expect, meanwhile if I have DSP System installed that version takes precedence and gives me errors.
Is this behavior correct or is it a bug to be reported to Mathworks? I inherited the code from which these lines are excerpted. I also inherited a Matlab license with several toolboxes I know little about (such as DSP System). Though I've been working with Matlab on and off for decades I've never encountered a case of a function with a "split personality" such as I'm describing with fdesign/design. So from my point of view (limited DSP knowledge) this looks like a bug, but it is possible in my lack of understanding these functions are working correctly with both toolboxes, and therefore I need to learn what I have done (or not done) to cause my errors.
