Summary

XFILT is a modern X Window based filter and group delay equaliser design system. It offers various levels of access expert mode for advanced users, interactive mode for users with some filter design experience and an automatic filter synthesis feature to assist those users without extensive design experience. The system is capable of designing filters and equalisers in passive-RLC, active-RC, transconductor-C, SC, SI and log-domain realisations with both classical and arbitrary approximations. Simulation features are also provided and a specialised optimisation feature is included which can aid the user in fine-tuning the design.

XFILT currently features:

Approximation

• standard functions
• arbitrary amplitude and high order touch points
• arbitrary group delay

Synthesis

• ladder based systems
  • passive prototype - automatic, interactive, expert mode
  • active RC, switched-capacitor, switched-current, transconductance-C, log-domain
  • canonic realisations
  • optimum scaling

• cascade biquads
  • optimum cascading
  • active RC, switched-capacitor, switched- current, transconductance-C, log-domain
  • optimum scaling

• multi-rate systems
  • switched-capacitor
  • switched-current

Realisation evaluation

• area cost
• sensitivity
• non-ideal effects
• noise

Optimisation

• correction of non-ideal effects

Availability

We can supply XFILT on Xbyte tape or cartridge formats. It comes pre-supplied with a suite of example designs and a tutorial guide/user manual. Please note that the software is not supported by a maintenance contract. Contact sewell@elec.gla.ac.uk for further information.

Interested users from the USA and Canada can access a display site at the University of Toronto - contact Professor Ken Martin.

The software is available under licence from the University - contact James Paris
at jparis@mis.gla.ac.uk for licensing details.