Match-n-Freq + Rainbow + CurvFit Software 4 Filter Designing
 Match-n-Freq a pulse shaping filter program that finds the pole-zero locations of a transfer function, H(s), for a matched filter. H(s) equals a -desired- signal (Yout) divided by a given input signal (Yin). Both Yout and Yin are functions of frequency (not time).
Group delay may also be calculated to compliment a given data set, thus, providing a flat group delay.
Minimizing Intersymbol Interference in a read/write channel for disc drives by shaping and slimming an isolated readback pulse was the main objective for writing this program. For more info, see Kost, R. and P. Brubaker; 'Arbitrary equalization with simple LC structures'; IEEE Transactions on Magnetics, Nov. 1981, pp 3346-3348.
Before you buy!
Try Match-n-Freq -before- buying it. Match-n-Freq may be freely downloaded by clicking here . Install Match-n-Freq and be sure it works okay for you before placing a bid. Match-n-Freq program is around 2 mbytes in size, and requires Windows 95 or 98 OS.
Rainbow (tm) allows you to find the best Spectral Estimation Method for your data's Power Spectral Density (PSD) plot. A menu of 10+ spectral estimators from Steve Kay's textbook, Modern Spectral Estimation, 1988, is available to choose from. The results differ dramatically from one estimator to another. Plus, varying input parameter and/or number of points may provide discrepancies. See how zero padding effects your results.
Estimation methods in Rainbow include Autocorrelation, Covariance, Prony, Akaike, Burg, Recursive Maximum Likelihood Estimation, Modified Yule-Walker Equations and others.
This picture/plot shows a PSD plot for one of the thirteen methods available to choose from. The methods can vary dramatically in their results. Try several before choosing which estimation is best to represent your PSD.
Manufacturing companies take note! Some estimators can detect signals 50 to 100 dB from main signal. See documented example! The unwritten rule of '30 dB is okay' (i.e. hidden) is no longer true.
See how zero padding effects ones results. Ability to change array sizes on the fly and thus show zero padding effect is/was main reason for writing this software.
Have sinusoidal data? Need a math model?
Do you have some data that needs a sinusoidal math model? Solution for a sine series to fit your data can be a hard problem for a solver. Try finding your data's main frequencies and enter them into our CurvFit program as initial starting values. Rainbow combined with CurvFit may provide an excellent math model for sinusoidal data.
Before you buy!
Try Rainbow -before- buying it. Rainbow may be freely downloaded by clicking here . Install Rainbow and be sure it works okay for you before placing a bid. Rainbow program is around 2 mbytes in size, and requires a Windows 95 or newer OS. Rainbow is shareware. Thus, you can share it with your friends.
 CurvFit (tm) is a curvefitting program for Windows 95/98. Lorentzian, Sine, Exponential and Power series are available models to match your data. A Lorentzian series is highly recommended for real data especially for multiple peaked and/or valleys data. CurvFit is an example of Calculus level programming... ie. minutes to solve, days or years to understand solution and what it implies (e.g. wrong model, sampling rate error, etc.). Helps learn
1) whether math model is good for given data;
2) convergence implies a reasonable solution;
3) how to select new starting initial parameter values.
See comments in example files (EX*.?) for ideas on how to converge via built in solver.
'Equation Calculator' feature is available to calculate your desired Y-value at any X-point once you have a math model for your given data.
Have some data? Want a math model?
Do you have some data that needs a math model? Learn the power of using a Lorentzian series as a math model for real data! Above picture is such an example.
This picture/plot shows an isolated pulse from a disc drive in the 1980s. A curvefit using 3 Lorentzians produced an excellent math model. The excellent fit convinced us that the Thin-Film-Head (TFH) was showing a 'bad' head for manufacturing. Thus Statistical Process Control procedures could be setup to 'find' and eliminate unwanted heads.
The isolated pulse model was used to estimate the InterSymbol Interference or peak shift for various code patterns on such a disc drive. The results were excellent. This work helped improve design testing and quality of end product. Could you use a math model to do basically the same thing ... i.e. reduce Time-to-Market for your project?
Before you buy!
Try CurvFit -before- buying it. CurvFit may be freely downloaded by clicking here . Install CurvFit and be sure it works okay for you before placing a bid. CurvFit program is around 2 mbytes in size, and requires Windows 95 or 98 OS.
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