MATLAB: Something wierd with sinc function

MATLABsinsinc

while using sinc(x) function there is a difference between sinc(x) and sin(x)/x also when i manually calculate its equal to
sinc(1.5)= -0.2 (negative value) sin(1.5)/1.5 = 0.6 (positive value)
why?

Best Answer

Sounds like you're using a pi-normalized sinc
      >> sin(1.5*pi)/(1.5*pi)
    ans =
       -0.2122
It's a normalization often used so that the roots of the sinc() will be at the integers.
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