The digital filter and speech communication

The study of speech communication and speech processing systems by simulation on a digital computer, and the design and physical implementation of these systems with discrete components, require a detailed knowledge of the elements known as digital filters. Following a definition of the digital filter, the different areas in which digital filters have been used in speech research and communication are explored. The basic theory relating to the design and application of digital filters is reviewed. Attention is given not only to the use of a general purpose computer to mechanize the simulation but also to the design of special purpose hardware to realize the digital filter as either an actual communication system component or as a laboratory research element. Following a discussion of several of the numerical problems that can arise in the design and utilization of digital filters, the paper concludes with a cursory look at some of the advantages and disadvantages of the use of digital filters in speech processing systems.