Software Download
VisualTFA proof of concept application.
This application is a build of all the functionality of my Measurement software with a UI which has been curtailed to perform only one function.
The UI implements Steve Temme's distortion plots from
AES E-Library » How to Graph Distortion Measurements
The input expects an impulse response (IR) in units of Pa, derived from a exp sweep stimulus.
AES E-Library » Simultaneous Measurement of Impulse Response and Distortion with a Swept-Sine Technique
Although if you don't care about THD measurements you can load any data file you want.
The input can be loaded via a CSV file, or by calling the appropriate functions by .NET from another program.
The program allows you to window the IR, input the Sampling rate, swept sine parameters, etc. Then performs CZT (
http://www.ingelec.uns.edu.ar/pds2803/Materiales/Articulos/0086rabi.pdf) on the IR and produces harmonic CZT plots for each harmonic selected. The program will compute THD in dB down from fundamental. All this can be performed pragmatically from another program via the .NET API.
Anyway, this was not my goal for this posting, but I am pushing my scheduled forward a bit, since my post may have been premature. I have included a License (
http://www.cascadeacoustic.com/VisualTFA/License.html) with the program which gives you pretty much free reign unless you want to resell parts of it. I will continue to use this license for all VisualTFA products which I release. The only fee-licensed versions will be those which are integrated with measurement software for DAQ and sound card devices.
Any software developers which download this may notice that there are hundreds of exposed methods which are not covered in the GUI application. None of these are fully tested yet. The next time I release a VisualTFA application I hope that it will live up to its name, and not just perform a FFT and THD analysis. My goal is that the application will provide, Fourier response (mag-phase), Instantaneous Amplitude (rho), Instantaneous Frequency (IF), Group Delay, and Magnitude on an IF-time axis. I am working on this as I write. I figured I would jump the gun and give a GUI a test beforehand with some backend code that was already written.
Download Link:
http://www.cascadeacoustic.com/VisualTFA/VisualTFA_Beta1.zip
http://www.cascadeacoustic.com/VisualTFA/Sample_IR.zip