ASN Filter Script: a new paradigm in bespoke filter design

ASN Filter Script: a new paradigm in bespoke filter design

Feature articles |
By Jean-Pierre Joosting

Editor’s note; Earlier in 2016 we carried an item on ASN’s Filter Designer Tool, which attracted considerable attention from EDN Europe readers; that report noted; …the package, for IIR and FIR filter design, offers and intuitive route to implementing digital filters that [ASN claims] represents the first significant advance in this class of tools for many years…a Windows-based package that assists with design of filters, primarily for implementation on processor targets, but also supporting floating point desktop algorithm development… structured to use an intuitive input approach that largely dispenses with entering parameters in text fields. Here, company director and algorithms and analytics specialist Sanjeev Sarpal describes an alternative method of executing filter design that also largely bypasses the high level of filter-specific expertise required by some conventional tools


The unique design experience offered by the tool enables users to create, analyse and verify their filter designs in a real-time interactive way, without the need of any complex mathematics. This new concept supersedes existing paradigms where design production was time consuming and restrictive.


Symbolic mathematics

ASN Filter Script allows designers to implement symbolic mathematical expressions directly. These may be definitions taken directly from textbooks, technical standards or even reference designs. As an example of simplicity and power of the language, consider the design of the following 2nd order IIR (infinite impulse response) notch filter, expressed as a conventional transfer function:



This transfer function may be simply mapped into the following Filter Script code:



Real-time interactivity

The scripting language offers designers the unique and powerful ability to modify parameters on-the-fly with the so-called interface variables, allowing for real-time updates of the resulting frequency response.


The complete code for the aforementioned transfer function is shown below, where the interface variable definition precedes the Main () section of the code.



The scripting language itself supports over 40 scientific commands and takes the best aspects of Scilab (the open-source software for numerical computing), R (the language structured for statistical computing and graphics), and ANSI C; and embodying approaches such as those seen in other commercial products such as Matlab – providing the designer with a familiar and powerful programming language, while at the same time allowing designers to implement complex symbolic mathematical expressions for their applications.


ASN Filter Script IDE

All developed code may be run within the tool’s IDE (integrated development environment), providing designers with a user-friendly development environment with all of the necessary functionality needed to successfully optimise the transfer function for the application considered. The IDE is fully compatible with the ASN Filter designer’s signal analyser, allowing designers to concoct a test signal and modify the design parameters on the fly – where, the effects on filtered output test signal can be seen in real-time.

Video clips on the tool are here and (in animated form) here.


Advanced solutions Nederland;



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