Tools That Fast-Track You To DSP Solutions

About Sketch-a-Filt


Sketch-a-Filt operates beautifully hand-in-hand with DSP Creations' Slifer companion product, giving the user a rapid two-pronged pathway from concept to greatly-refined design. In this style of usage, Slifer can provide radical bolt-on changes to the initial design, including windowing, direct precision gain modification in a narrow band, and imposition of fractional-sample delay or other desired nonlinear phase properties.

Sketch-a-Filt Features at a Glance
    A Wealth of Filters to Select
  • Real-coefficient and complex-coefficient IIR and FIR filters
  • Real and complex FIR filters having either linear- or nonlinear-phase characteristics
  • Minimum-phase and maximum-phase conversion with pushbutton ease
  • Three FIR and three IIR filter design styles available for simultaneous comparisons;a further three dozen assorted IIR/FIR methods by single edit step;
  • High-fidelity IIR approximation of FIR filters; almost-linear-phase IIR passbands
  • Target smoothing yields equivalent windowing effects for IIR
  • Time-offset impulse responses; Nyquist zero-forcing for prescribed time zeros
    Incorporate Your Own Contibutions in the Tool
  • Guest filters of any style importable; retain your best for long-term reference
  • Embed your own User-Defined m-code to support designs employing special algorithms of your choosing
  • Pushbutton import/export of designs to MATLAB Workspace, FVTool or SPTool or DSP Creations' Slifer for further refinement or embody as detailed Simulink blocks
    Rich Range of Specification, Display and Measurement Options
  • Simply freehand sketch the gain and phase/group delay shapes you want
  • Sketch directly with Linear or dB gain scaling, with normalized or arbitrary frequency calibration
  • Complex or purely real/imaginary spectral targets easily invoked
  • Abundant Target-Profile sketching support
  • Resampling, smoothing and endpoint gain control for precision-shaped gain transitions
  • Unique Target Profile Calculator for flexible programatic generation of designs
  • Single-sided or double-sided frequency viewport with locked spectral Hermitian symmetry optional
  • Approximation errors displayed and measured
  • Set-points and set-bands available by pushbutton
  • Linear gain segments at exact frequency and gain breakpoints
  • Erase/overwrite gain segments with ease
  • Precision ripple and transition Quality Measurements for flat-top-gain filters; easy bar-chart performance ranking
  • Up to 8 overlaid filter design credential plots for comparisons of gain,impulse responses and Pole-Zero Patterns
System Requirements
  • Any version of MATLAB® (version 7.5 [that is, Release R2007b] up through version 9.10 [that is, Release R2021a] ), along with a corresponding version of the Signal Processing Toolbox™ (available from the The MathWorks Inc.)
  • Computing platforms: See roadmap of all corresponding MATLAB platforms.
Currently Sketch-a-Filt Is Not Available For Standalone Purchase
  • All three of our software products are incorporated into the software package supporting the Training Courses described under "Services" on this website.
  • To arrange an on-site course please contact Dr. Gerald D Cain, Email: