Speech Enhancement Implementations in the Digital, Analog, and Hybrid Domain

The general quality of speech or important speech parameters such as the intelligibility, clearness or naturalness of speech can be emphasized by signal processing. Such processing for improving speech quality can be found in telecommunication applications, e.g. mobile telephony, internet telephony or personal intercom. By careful selection of domain for realization, i.e. digital, analog, or hybrid, implementation specific benefits can be utilized to increase the speech quality or performance. This paper stresses some key characteristics of the three implementation domains with emphasis on speech enhancement applications. A robust, low complexity, speech enhancement algorithm will be highlighted to illustrate the advantages (and disadvantages) of a purely digital, a purely analog, and a hybrid digital-analog implementation.