Hardware-software configuration for high performance digital filtering in real-time

A general purpose digital-filtering system is described, which combines high performance digital hardware with ergonomic, efficient and close-to-optimum software. The system is highly versatile and can be reprogrammed with frequency/phase or impulse response characteristics to arbitrary specification. The robust hardware is suitable for laboratory or field-trial use and can sustain real-time operation to 60kHz sampling rate. The filter is based on a 512-point FIR implementation, loaded from and specified on a micro-computer. The software for pre-computing the filter\´s impulse response is based on the highly efficient technique of "Host Windowing" developed by Abed and Cain (4). Areas of application of the system include: network equalisation and phase correction, anti-alias, partial-response or matched filtering, echo cancellation, wideband differentiation, Hilbert transforms and SSB modulation by filtering or phasing methods.