An Astounding Digital Filter Design Application
I've recently encountered a digital filter design application that astonished me with its design flexibility, capability, and ease of use. The software is called the "ASN Filter Designer." After experimenting with a demo version of this filter design software I was so impressed that I simply had publicize it to the subscribers here on dsprelated.com.
What I Liked About the ASN Filter Designer
With typical filter design software packages the user enters numerical values for the desired filter's parameters such as cutoff frequency, stopband attenuation, etc., hits a "design" button, and is presented with a frequency magnitude response curve and a list of filter coefficient values. If you want to change the filter's frequency-domain performance you have to start over and re-enter new desired numerical parametric values. Not so with the ASN Filter Designer software! Here's why.
With the ASN software, when you first specify your desired parameters you'll see the following main window:
To change the filter's frequency-domain performance you merely use your computer's mouse to click on the little red squares ("Markers") and move them around in the frequency response plot. That will automatically change the frequency response curve and the z-plane pole/zero locations, as well as update the filter's coefficients. No new numerical data entry is needed!
Once a high-order IIR filter is designed it can be converted to a cascade of 2nd-order biquad IIR sections to enable a stable filter implementation using fixed-point arithmetic.
Designing Specialized Filters
The Filter Designer allows you to design specialized filters by way of manipulating the pole/zero locations using your computer's mouse. For example, you can design a lowpass IIR filter and then manually position a pair of conjugate zeros so that they reside at 60 Hz (or 50 Hz) to provide a deep frequency response notch in order to highly attenuate AC power-line spectral noise.
Signal Analyzer Capability
As if the easy filter design capability weren't enough, the software designers also provide a way for the user to specify test signals that are applied to the input of the designed filter. This means you can monitor the output of a designed filter (in both the time and frequency domains) in real-time as you manually manipulate the filter's frequency response 'markers' or z-plane poles or zeros. I know of no other filter design software with that powerful capability.
Filter Scripting Language
Remarkably, the Filter Designer also allows the user to write mathematical scripts that compute the numerator and denominator coefficients of a desired filter's z-domain transfer function. Similar to MATLAB and Octave, this capability enables the user to easily design filters defined by mathematical equations such as the filters described in: https://www.dsprelated.com/showarticle/972.php
Better than I can do here with my words, you can see a videos describing the ASN Filter Designer software at:
The ASN Filter Designer appears to be the Swiss Army Knife of filter design software packages. The software's designers seem to have thought of everything! If you're interested in digital filters, check out this software—you'll be glad you did.
I realize this blog makes me look like a salesman for the ASN Filter Designer software. I'm no salesman, I've written this blog out of pure enthusiasm.
Appendix A: Downloading a Demo Version of the Filter Design Software
web address, scroll down until you see the following:
To download a demo version of the ASN Filter Designer software, click on the blue down-pointing arrow. The available 'User's Guide' shows how to install the demo version of the software on your computer.
Appendix B: Downloading the User's Guides (Manuals)
web address, scroll down until you see the following:
Click on the '[+] Documents' line item to see the following:
Click on the two PDF
symbols to download the two User's Guides.
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The Swiss Army Knife of Digital Networks
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Implementing Impractical Digital Filters
I wouldn't buy it for serious work as I can use Matlab etc to same effect. It is not useful for advanced filter designers of say equalisers, multirate systems and techniques of reducing resource at implementation.
My understanding is that in the US credit cards are the preferred way of purchasing products/services, but its too bad that (although SWIFT is supported) wire transfers are discouraged by US banks. This is quite different to Europe where wire transfers are the norm, and all personal/business bank account packages offer international wire transfers in all major currencies as standard. Funnily enough, credit card payments are discouraged due to the extra costs involved.
For the moment we hope that discouraged is not interpreted as impossible, since we have successfully sold licenses to a few US corporations. In addition, please bear in mind that all clients outside the EU are VAT (value added tax) exempt, which is in essence a 21% discount. This discount should cover a majority of the bank service costs.
Well look closely over the next month or so for an alternative solution that is closer to the US/Canada market concept.
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