The development of a portable real-time display of voice source characteristics

The use of real time visual displays by speech and language therapists for the representation of voice source characteristics such as fundamental frequency (F0) and electrolaryngographically (Lx) derived vocal fold closed quotient (CQ) is now well established. This trend has been made possible by the widespread availability of fast computers and dedicated signal processing devices. However, many users of such equipment have expressed a need for a portable, battery operated device displaying F0 and CQ, not only for specific use by the therapist but also for the use by clients outside the usual clinical consultation where appropriate. At the University of York, we have developed a portable hand-held system based on the electrolaryngograph output waveform and a high performance microcontroller chip. The system can display graphically against time measures of f/sub 0/, larynx CQ and a normalised display of individual Lx cycles. The paper describes the development, implementation and basic operation of the voice analyser system.