"pnachtwey" <pnachtwey@gmail.com> schrieb im Newsbeitrag news:4e8b1657-7e35-4630-9090-298b23d6b8ea@u7g2000yqm.googlegroups.com...> On Jan 9, 1:55 am, "JCH" <ja...@nospam.arcornews.de> wrote: >> "Laron" <jason.pi...@inbox.com> schrieb im >> Newsbeitragnews:BOednfutGppmrtnWnZ2dnUVZ_uWdnZ2d@giganews.com... >> >> > Hi, >> > When simulate the FIR filter response, run interp(Matrix,n) in >> > matlab, >> > the maximum of Matrix is 1,but the response is larger than 1? >> > I wonder know why this could be happen and how to degrade this >> > effect? >> >> You possibly have an ODE (system) of 2nd degree: >> >> See Page 1 >> *http://home.arcor.de/janch/janch/_control/20100109-overshooting/ >> 0,0001 u'' + 0,01 u' + u = w >> >> See Page 2: Degrading using higher damping >> 0,0001 u'' + 0,018 u' + u = w >> >> -- >> Regards JCH > This has nothing to do with the original question. Laron wants to > know how to INTERPOLATE without OVERSHOOTING.A 'possible' alternative explaination could be a bad DFT approximation (Gibbs phenomenon). I don't like calling it interpolation in this context. What you see here is approximation: * http://home.arcor.de/janch/janch/_control/20100110-dft/ -- Regards JCH
Interpolation response overshoot, why?
Started by ●January 6, 2010
Reply by ●January 10, 20102010-01-10
Reply by ●January 10, 20102010-01-10
pnachtwey wrote:> On Jan 6, 4:41 pm, jim <"sjedgingN0Sp"@m@mwt,net> wrote: > > Laron wrote: > > > > > I just know there would be a lpf, not quite sure about the reconstruction > > > process. > > > I got an idea that the overshoot caused from the lpf, but the detail "how" > > > is still not clear. > > > > A low pass filter with only positive values and a DC gain of 1 will > > guarantee no overshoot. > > > > -jim > But that is not interpolating.And why would you say that? Take his example of [1 0 1 1 0 1]. Stuff it with 0 so that it becomes [1 0 0 0 1 0 1 0 0 0 1 0] Low Pass Filter with [1/2 1 1/2] and you get [1 .5 0 .5 1 1 1 .5 0 .5 1] In practice this will be done more efficiently by filtering the original with [1/2 1/2] and interleaving the filtered result with the original sequence. -jim
