"Jerry Avins" <jya@ieee.org> wrote in message news:iNqdncOlvb8dkPnVnZ2dnUVZ_oHinZ2d@rcn.net...> Dilip V. Sarwate wrote: >> "Jerry Avins" <jya@ieee.org> wrote in message >> news:M_mdnU5ezfGBOv7VnZ2dnUVZ_jGdnZ2d@rcn.net... >>> raj wrote: >>>> Your response [1 1 1 1] contains no step. It could be a sample of a DC >>>> value. >>>> >>>> Yes i agree with you ...but i am confused here since there are only >>>> four value coefficients. >>> Before going further, let's clear something up. Are you really saying >>> that the number of samples to be filtered may not exceed the number of >>> coefficients in the filter? Imagine filtering a half-hour-long symphony >>> on a CD. Take it from there. >>> >>> ... >>> >>> Jerry >>> -- >>> Engineering is the art of making what you want from things you can get. >>> ����������������������������������������������������������������������� >> >> In fact, maybe it is time to get back to basics. The phrase "unit step >> response" >> is commonly understood to mean the response of a system -- an FIR filter >> in this instance -- to a unit step function, where by "unit step >> function" is meant the signal u[n] where u[n] = 0 for n < 0 and u[n] = 1 >> for >> nonnegative values of n, viz., n = 0, 1, 2, ... The response y[n] of an >> FIR filter to u[n] consists of a transient followed by a steady-state >> output. Specifically, if the impulse response of the FIR filter is h[0], >> h[1], h[2], ... , h[m], and h[i] = 0 for i > m, then the unit step >> response of the FIR filter is >> >> y[0] = h[0] >> y[1] = h[0] + h[1] >> y[2] = h[0] + h[1] + h[2] >> ...... >> ....... >> y[m] = h[0] + h[1] + h[2] + .... + h[m] > > ... > >> The response of the FIR filter to the unit step function u[n] is >> different from its response to the "rectangular pulse" signal x[n]. >> Should this >> difference puzzle the denizens of comp.dsp so much? > > Of course you are right. I thought it wise to undertake the explication > one step at a time. When a concept seems to have been fundamentally > misunderstood, it is often vest to address one issue at a time. Is that > too pompous? > > Jerry > -- > Engineering is the art of making what you want from things you can get. >Jerry, Nah. Just means there's an "S" in your Meyers-Briggs. Fred
unit step response doubt
Started by ●June 25, 2008
Reply by ●June 30, 20082008-06-30
