Formant Filters Designs with Adjustable Characteristics

A topology which is suitable for emulating the filtering operation performed by the vocal tract is presented in this work. The main offered advantage is that the frequency characteristics can be electronically tuned, in the case that Operational Transconductance Amplifiers are employed as the active elements, or digitally, in the case that a Field Programmable Analog Array device is utilized. This imparts versatility to the introduced structures, in the sense that they can be used for extracting different vowels from the corresponding glottal source pulses. The provided simulation and experimental results validate the findings of this work.