Tsuyoshi Ideguchi

Influence of the Sensation of Vibration on Perception and Sensibility while Listening to Music

We examined how the sensation of touch influenced the perception of sound and its effect on sensibility. This was assessed in subjects listening to music in conjunction with experiencing the vibrations produced by a low-tone rhythm musical instrument such as a base. Physically experiencing the vibrations produced by the base appeared to increase the clarity of the base sound and that the sound source appeared to become closer. In addition, the sensation of being playing a base instrument was experienced.

Mesh grounding to suppress potential differences between telecommunications equipment caused by direct lightning strikes

When lightning hits a building, telecommunications equipment within the building is occasionally damaged due to induced voltage in the telecommunications cables, power-feeding cables, and grounding wires installed in the building. This induced voltage is caused by the lightning current flowing into the pillars and girders of the building. To suppress these induced voltages, mesh-wiring and branch-wiring grounding systems have been designed to protect connected devices from lightning. However, there have been few experimental reports and little quantitative analysis on the efficiency of these grounding systems. Therefore, we have studied the impedances of pillars and girders, and the lightning current distribution in a building, through experiments using an actual reinforced concrete building. In this article, based on our previous results concerning the lightning current distribution, we investigate the induced voltage in the grounding wires experimentally and theoretically. From the relationship between the current distribution in the pillars and girders, and the induced voltages in the grounding wires installed in the floor, we found that the induced voltages can be estimated by applying vector-potential methods to the current in the girders. By measuring the induced-voltage differences between a single-wiring, a branch-wiring, and a mesh-wiring grounding system, we also found that the mesh-wiring system provides the best protection for the telecommunications equipment and reduces the induced voltage between devices to one-fifth of that with the single-wiring or branch-wiring systems.

A method to estimate normal mode noise voltage induced on indoor telecommunication lines due to adjacent AC supply lines

When metallic telecommunication lines carrying digital signals are laid adjacent to ac supply lines in an office or a house, then the noise generated by the ac supply lines is induced on the telecommunication lines and the quality of transmission may be degraded. To calculate the induced voltage generated directly between the cores of a telecommunication line requires accurate values of the coupling admittance or coupling impedance between the two lines corresponding to the cable construction and the problem becomes very complicated. This paper proposes a simple method of estimating the voltage induced between the cores of a telecommunication line when the telecommunication line is laid adjacent to an ac supply line. The amount of coupling from the primary circuit with an open-circuited terminal and with a short-circuited terminal to the secondary circuit is measured. Using this value, the characteristics of the induced voltage corresponding to an arbitrary value of terminal impedance of the primary or secondary circuit simply are estimated. The validity of the estimation method was confirmed by experiments.