SKETCH-A-FILT, A TOOL FOR DESIGNING
DIGITAL FILTERS BY SIMPLY SKETCHING
DSP Creations Ltd is pleased to announce the release of Sketch-A-Filt, a MATLAB-based conceptualization tool which allows digital filter design to be done with unparalleled ease. This package enables you to merely make a rough sketch of the desired gain curve through the use of your PC mouse. Thoroughly unconventional shapes, defying the limited standard textbook flat-topped targets, are instantly designed and their coefficients are displayed and available, even as you sketch and make gain modifications.
Sketch-A-Filt empowers you to conceive and receive any gain characteristic that might suit your whim or your toughest industrial specification. Linear Phase is assigned automatically, and you need never to resort to any equations or calculations - simply decide upon the size of your coefficient budget and shape your filter with our sketchpad. Pushbutton conversion to Minimum-Phase and Maximum-Phase handily exhibits important extreme FIR variants. IIR designs to arbitrary target profiles are also obtained at the tick of a checkbox.
You can create imaginative wiggly gain curves to see the flexibility and diversity of the highly-regarded Frequency-Sampling, Least-Squares and Remez approaches to FIR approximation of your spec, along with economy solutions afforded by two powerful IIR techniques. You can start by drawing crude approximations to real-life filter specs and making progressive refinements by dragging individual gain points or gain plateaus across bands to any frequency or gain location wanted. Effects of decreasing or increasing the number of FIR coefficients or IIR order are always easy to quantify and assess.
Elaborate, but friendly, drawing package features support a well-integrated range of erasure, smoothing, segment-setting and interpolation tasks that facilitate and accelerate effortless sketching. The whole process is highly intuitive and more like wishing than designing. All you have to do is reap the rapid benefits!
Sketch-A-Filt Features at a Glance
Real-coefficient and complex- coefficient linear-phase FIR filters
Real and complex nonlinear-phase FIR filters
Minimum-phase and maximum-phase conversion with pushbutton ease
Three FIR and three IIR filter design styles available for simultaneous comparisons; Guest filters of any style importable; embed your own User Defined design code; a further 10 IIR/FIR methods by single edit step
IIR filters of any order readily selectable; two complex, one real
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 zeroes
Simply freehand sketch the gain and phase/group delay shapes you want
Unique Target Profile Calculator for flexible generation of designs
Single-sided or double-sided frequency viewport
Locked spectral Hermitian symmetry optional
Complex or purely real/imaginary spectral targets easily invoked
Approximation errors displayed and measured
Precision ripple and transition Quality Measurements; easy performance ranking
Set-points and set-bands available by pushbutton
Linear gain segments at exact frequency and gain breakpoints
Erase/overwrite gain segments with ease
Resampling, smoothing and endpoint gain control for precision-shaped transitions
Sketching directly with Linear or dB gain scaling
Normalized or arbitrary frequency calibration
Pushbutton import/export of designs to MATLAB Workspace, FVTool or SPTool or DSP Creations Slifer for further refinement or embody as detailed Simulink blocks
Price and Availability
Sketch-A-Filt is available PC/Unix platforms now, at a cost of £400 * per license. Simply email information@dspcreations.com, to arrange payment and delivery details.
Users must have MATLAB version 7.0.1 (or 7.0.0 or 6.5.1) along with version 6.2.1 (or 6.2 or 6.1) of the Signal Processing Toolbox (available from the MathWorks Inc. at mathworks.com). 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.