Signal Wizard v. 2 from UMIST

The Signal Wizard 2 from UMIST is a unique, integrated system for designing, downloading and running very high performance filters in real-time. It includes the high-level PC-based software interface that designs the filter according to the user's requirements, a hardware module based on an advanced digital signal processor and a low-level firmware operating system that implements the filtering operations. Once designed, an integrated software interface is used to download the filter to the hardware module via a serial link where it is executed on demand. Most important, the system requires no knowledge of digital signal processing (DSP) theory on the part of the user, or of the mathematics associated with digital filter design.
The Signal Wizard is a total solution package. Due to its flexibility, it is particularly well suited to the real-time processing of audio signals. High quality analogue signal conditioning and a stereo 24-bit resolution codec provide extremely high resolution, sufficient for the most demanding applications. In short, The Signal Wizard 2 brings the power of digital signal processing to any audio-bandwidth domain that requires electronic signal filtering. Applications include audio signal processing, sensor signal conditioning, signal analysis, vibration analysis, education and research in electrical, electronic and other physical sciences.
New features added for Signal Wizard 2 include
- True stand-alone operation (without PC) once configured;
- IIR and adaptive filters;
- True dual channel operation;
- Impulse response import;
- Real or complex fre-quency response import;
- Delay options for in/out and FIR filter modes;
- Real-time spectrum analyzer;
- 6x faster operation;
- Off-line filter mode for wave (WAV) files.
Low pass, high bass, multi-ple band-stop / band-pass filters may be combined to produce very complex filters for frequencies up to 24 kHz, as well as standard infinite impulse response (IIR) and adaptive types. The software can also accept measured responses to define a filter template. This can be used to provide measurement equalisation or to search out signal signatures in noisy environments. In fact, it is a simple matter to produce filters with completely arbitrary frequency magnitude and phase characteristics using the finite impulse response (FIR) method, with no phase distortion, no matter how sharp the filter is.Alternatively, arbitrary phase distortion can be introduced if this is desirable.
It is even possible to design and execute real-time deconvolution (inverse) filters using the special invert mode. Because the processing module is so fast, it is possible to design filters with responses far beyond what is possible with traditional analogue techniques.
The control program runs under Windows, and provides a user-friendly filter design tool that de-mystifies the process of specifying the filter. The filter design process simply becomes one of describing the desired frequency response. The design package indicates the response that will be produced and also the deviation from that specified. User designs may be stored for re-use and actual responses may be entered from measurements for simulation or equalisation purposes. The filters are calculated and downloaded to the hardware within seconds.

Patrick Gaydecki, School of Electrical and Electronic Engineering, University of Manchester, P.O. Box 88, The Faraday Building, Manchester M60 1QD.