Module 2: The z-transform and poles-zeros
The interactive Pole-Zero chart editor allows you to move the poles and zeros around with a mouse, zoom, pan the chart etc and graphically fine-tune designs to your exact requirements and see the effects on the frequency response in real-time. As seen on the right, this is especially useful for the classroom, whereby a lecturer can explain to students the effect of the poles-zeros on the net frequency response without diving into the mathematics first, which is where many students become confused.
ASN FilterScript is a symbolic math scripting language, used for implementing specialised transfer functions in real-time (Live Math Scripting).
The ‘live IDE’ 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. This has the advantage of allowing the designer to see how the coefficients of the symbolic transfer function expression affect the frequency response and the filter’s time domain dynamic performance. Definitions may be taken from textbooks, technical standards or even reference designs and implemented within minutes.
The scripting language supports over 65 scientific commands (trigonometrical, vector, general math and filter design methods – see the section on Digital filter design for the details) and provides designers with a familiar and powerful programming language, while at the same time allowing them to implement complex symbolic mathematical expressions for their filtering applications.
Several detailed practical examples are also provided with the software bundle, allowing experimenters to get quickly up to speed with scripting language and writing their own application scripts.