Hello to all, Dear i am trying to resample the irregularly sampled data regularly, in order to apply the standard spectrum analysis techniques on it. For this purpose i am using linear interpolation. But there exist interpolation noise, so kindly tells me the methods to reduce the interpolation noise. I shall be thank full to you for your Help. Regards. Qaisar This message was sent using the Comp.DSP web interface on www.DSPRelated.com

# Interpolation noise when we resample the irregularly sampled data regularly

"qaisar" <alsaeed86@yahoo.com> wrote in message news:b9GdnStK4_htJsvfRVn-1w@giganews.com...> > Hello to all, > > Dear i am trying to resample the irregularly sampled data regularly, in > order to apply the standard spectrum analysis techniques on it. For this > purpose i am using linear interpolation. But there exist interpolation > noise, so kindly tells me the methods to reduce the interpolation noise. > > I shall be thank full to you for your Help. > > Regards. > > QaisarThere was a long thread here on that subject maybe a year ago. You could Google for it.... Fred

http://groups-beta.google.com/group/comp.dsp/browse_thread/thread/8e8704781babe1e7/9621af7ea381f01c?q=resample+irregularly+sampled+data&rnum=3#9621af7ea381f01c

"Peter K." <p.kootsookos@iolfree.ie> wrote in message news:1113014323.367665.221520@g14g2000cwa.googlegroups.com...>http://groups-beta.google.com/group/comp.dsp/browse_thread/thread/8e8704781babe1e7/9621af7ea381f01c?q=resample+irregularly+sampled+data&rnum=3#9621af7ea381f01c>and: http://groups-beta.google.com/group/comp.dsp/browse_frm/thread/aa2be6819f584d85/4076738cb693e9f8?q=comp.dsp:+Fred+Marshall+interpolation+linear+audio&rnum=1#4076738cb693e9f8 Olli Niemitalo

In article <b9GdnStK4_htJsvfRVn-1w@giganews.com>, qaisar <alsaeed86@yahoo.com> wrote:>Dear i am trying to resample the irregularly sampled data regularly, in >order to apply the standard spectrum analysis techniques on it. For this >purpose i am using linear interpolation. But there exist interpolation >noise, so kindly tells me the methods to reduce the interpolation noise.You could use a higher-order interpolation than linear. I seem to recall that someone in this newsgroup pointed out a paper which related higher order Lagrangian interpolation to band-limited windowed-sync interpolators (which are often implemented by table lookup in the so-called multiphase technique). I wonder if non-uniformly spaced higher-order interpolation might then relate to some sort of non-symmetric warped window-sync weighting functions? (with a warping function related to the distance(s) to n nearest neighboring sample points?) If so, maybe multiphase interpolation could still be used, but with some sort of warped phase table indexing algorithm? IMHO. YMMV. -- Ron Nicholson rhn AT nicholson DOT com http://www.nicholson.com/rhn/ #include <canonical.disclaimer> // only my own opinions, etc.

>In article <b9GdnStK4_htJsvfRVn-1w@giganews.com>, >qaisar <alsaeed86@yahoo.com> wrote: >>Dear i am trying to resample the irregularly sampled data regularly, in >>order to apply the standard spectrum analysis techniques on it. Forthis>>purpose i am using linear interpolation. But there exist interpolation >>noise, so kindly tells me the methods to reduce the interpolationnoise.> >You could use a higher-order interpolation than linear. > >I seem to recall that someone in this newsgroup pointed out a >paper which related higher order Lagrangian interpolation toband-limited>windowed-sync interpolators (which are often implemented by table lookup >in the so-called multiphase technique). I wonder if non-uniformlyspaced>higher-order interpolation might then relate to some sort ofnon-symmetric>warped window-sync weighting functions? (with a warping function >related to the distance(s) to n nearest neighboring sample points?) >If so, maybe multiphase interpolation could still be used, but with some >sort of warped phase table indexing algorithm? > > >IMHO. YMMV. >-- >Ron Nicholson rhn AT nicholson DOT com http://www.nicholson.com/rhn/>#include <canonical.disclaimer> // only my own opinions, etc. >Dear its a nice idea but the use of multiphase interpolation for irregularly sampled data makes then algorithm quiet complex and requires more and more computational efforts. Can someone tell me that how much interpolation error is acceptable, inorder to have a spectrum with appropriate accuracy. Is there some defined limit on interpolation error and spectrum quality. Thanks in advance for your ideas. This message was sent using the Comp.DSP web interface on www.DSPRelated.com