Phonation threshold pressure measurement with a semi-occluded vocal tract.
ABSTRACT The purpose of this article was to determine if a semi-occluded vocal tract could be used to measure phonation threshold pressure. This is in contrast to the shutter technique, where an alternation between a fully occluded tract and an unoccluded tract is used.
Five male and 5 female volunteers phonated through a thin straw held between the lips. Oral pressure behind the lips was measured. Mathematical predictions of phonation threshold pressures were compared to the measured ones over a range of frequencies.
It was shown that, for a 2.5-mm diameter straw, phonation threshold pressures were obtainable over a 2-octave range of fundamental frequency by all volunteers. In magnitude, the pressures agreed with the 0.2-0.5 kPa values obtained in previous investigations. Sensitivity to viscoelastic and geometric properties of the vocal folds was generally not compromised with greater oral impedance, but some differences were predicted theoretically in contrast to an open mouth configuration.
Because phonation threshold pressure is always dependent on vocal tract interaction, it may be advantageous to choose an exact and fixed oral semi-occlusion for the measurement and interpret the results in light of the known acoustic load.
Conference Proceeding: The MSAT-X MARECS B2 satellite experiment: ground segment results[show abstract] [hide abstract]
ABSTRACT: The results of a recently completed satellite experiment employing the JPL MSAT-X developed land-mobile satellite communication terminal are described. In this experiment, a full duplex 4800-b/s digital data and voice communication link was established through the INMARSAT MARECS B2 satellite between Atlantic City, New Jersey, and Southbury, Connecticut. A series of experiments was performed to characterize the terminal performance over this link. The basic experimental setup and the preliminary results of the speech and data experiments are presented. The satellite environment proved to be near to what was expected, and as a result the experimental results were very close to theory/simulation/laboratory experiments. It was found that the ground-to-ground communication links were more benign links than the ground-to-air and air-to-ground links, and this is reflected in the improved margins for the ground-to-ground links (approximately 5 dB versus 3.2 dB for the aeronautical linksGlobal Telecommunications Conference, 1989, and Exhibition. Communications Technology for the 1990s and Beyond. GLOBECOM '89., IEEE; 12/1989
Conference Proceeding: Packet-switching network of dynamic architecture based on artificial intelligence[show abstract] [hide abstract]
ABSTRACT: A method of designing packet-switching network of dynamic architecture based on artificial intelligence is discussed in detail. According to this method, the intelligent information about the user's requirements and network states is used to control the network architecture's exchange so that its information transmission efficiency is increased greatly. Some technical problems and experimental results concerning this dynamic-architecture packet-switching network (DAPSN) are examined. It is suggested that the design principle of DAPSN can be widely applied in many computer networks, for example, the MAN, WAN, LAN, (metropolitan, wide, and local area networks), andISDN (integrated services digital network)Global Telecommunications Conference, 1989, and Exhibition. Communications Technology for the 1990s and Beyond. GLOBECOM '89., IEEE; 12/1989