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  • Impulse invariance method

    From gyansorova@gyansorova@gmail.com to comp.dsp on Tue Nov 12 12:10:58 2019
    From Newsgroup: comp.dsp

    I have a laplace transfer-function

    G(s)=k(1+sT)/s*2

    which I need the discrete-time version G(z) using impulse invariance method.

    Using partial fractions I get

    G(s) = c1/s + c2/s^2

    c1=kT and c2=k

    However when I use Matlab c2d and select "impulse" it gives me a different version though the first term c1 is right. Matlabs second term c2 is negative.

    I assume for multiple poles something is different.

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  • From gyansorova@gyansorova@gmail.com to comp.dsp on Tue Nov 19 10:34:22 2019
    From Newsgroup: comp.dsp

    On Wednesday, November 13, 2019 at 9:11:02 AM UTC+13, gyans...@gmail.com wrote:
    I have a laplace transfer-function

    G(s)=k(1+sT)/s*2

    which I need the discrete-time version G(z) using impulse invariance method.

    Using partial fractions I get

    G(s) = c1/s + c2/s^2

    c1=kT and c2=k

    However when I use Matlab c2d and select "impulse" it gives me a different version though the first term c1 is right. Matlabs second term c2 is negative.

    I assume for multiple poles something is different.

    Sorted it. Forgot that a double integrator has a Ts^2 term
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