Publisher Summary Computer-based technologies have become the norm in neurophysiology laboratories. The development of commercial and individual applications has made the personal computer a versatile neurophysiological workstation. The development of commercial and individual applications has made the personal computer a versatile neurophysiological workstation. The successful transfer of techniques and processes from the analog realm of bioelectric potentials to that of the digital world of the computer requires understanding of the underlying limitations of the digital representation of bioelectrical potentials. This chapter describes the implementation of digital filters, the mathematical operations on digitized data that are similar to setting filter selections on an amplifier. The use of digital filters cannot be applied as freely as turning a knob on the amplifier to change analog filtering characteristics. The reason for this is the nature of digital information. Whereas analog data is a continuously varying voltage with a value at any point in time, the digitally converted data is a list of numbers that represent voltages at discrete, equally spaced, time points. The digital signal retains no information between sampling points and thus, information between samples is lost. The actual situation with digital signal processing is best described in terms of the frequency components of the signal.
