Multi-band infinite impulse response filtering using microcontrollers for e-Monitoring applications

This paper introduces the design and implementation of a simple yet efficient technique for Infinite Impulse Response (IIR) bandpass filters that can be used for simultaneous multiple frequency estimation applications. The technique, which is implemented on a dsPIC microcontroller, uses variable data sampling rates and a table of predefined filter coefficients simultaneously to dynamically adjust its pass band precisely to the range of interest. The technique developed may be deployed to provide a more reliable and efficient algorithm which can be flexibly utilised as part of a modular development of high performance, reliable sensing systems. The developed system is described in detail in the context of the e-Monitoring of a milling cutting process. In this case spindle speed and spindle load signals from a machine tool have been used as a source of information relating to the health of the cutting process being undertaken.