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Filter a Rectangular Pulse with no Ringing

Filter a Rectangular Pulse with no Ringing

Neil Robertson
TimelessIntermediate

To filter a rectangular pulse without any ringing, there is only one requirement on the filter coefficients: they must all be positive. However, if we want the leading and trailing edge of the pulse to be symmetrical, then the coefficients must be symmetrical. What we are describing is basically a window function.


Summary

This paper shows that eliminating ringing when filtering a rectangular pulse requires only that all FIR coefficients be positive, and that symmetric coefficients produce symmetric leading and trailing edges. It frames the result as a window-function perspective, connecting simple coefficient constraints to time-domain pulse behavior and trade-offs in spectral leakage.

Key Takeaways

  • Recognize that all-positive FIR coefficients prevent ringing in the filtered rectangular pulse.
  • Design symmetric coefficients to enforce identical leading and trailing edge shapes.
  • Interpret common window functions as FIR filters whose sign and symmetry determine time-domain ringing and symmetry.
  • Apply simple window choices to trade off transition width and sidelobe behavior while avoiding ringing.

Who Should Read This

DSP engineers and researchers (filter designers, communications or audio/radar engineers) who want quick, practical insight into designing FIR/window-based filters that avoid pulse ringing while preserving edge symmetry.

TimelessIntermediate

Topics

Filter DesignFFT/Spectral Analysis

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