Recording Technology & Mechanical Engineering

Ultra-high-density Perpendicular Magnetic Recording Studies

Takahiko TAMAKI, Senior Research Engineer, Recording Technology & Mechanical Engineering The spread of HDTV and multi-channel broadcasting means that program transmitters and receivers must handle a massive amount of data. This will increase the need for recording systems with large capacities and high data transfer rates. Our group is promoting research on magnetic recording heads and perpendicular magnetic recording media (the direction of the recording magnetization is directed perpendicularly to the recording surface). We are working to improve amorphous materials suitable for high-density recording and to enhance the performance of the yoke-type head by using tunneling magneto resistive elements as magnetic sensors. Our goal is to record two hours or longer of digital HDTV programming on a disk the size of a 100-yen coin. This medium will have application in various broadcasting recording systems, including home servers and portable receivers. Obviously ultra-high density recording will be important in the future, so we are determined to pursue this research with the aim of improving broadcasting technology.

Digital Satellite Broadcasting Systems

Research on Advanced Satellite Broadcasting Systems

Yutaka KAWAGUCHI, Senior Research Engineer, Digital Satellite Broadcasting Systems Digital BS broadcasting allows a viewer to receive information provided via data broadcasting services, while simultaneously enjoying a clear Hi-Vision (HDTV) service. It is expected that in the future such multimedia broadcasts will be combined with the Internet, thus becoming a virtually indispensable information source for daily living. Digital BS broadcasting currently employs a 12-GHz-band radio wave. Future satellite broadcasting systems featuring more diverse services will probably use higher frequencies, such as the 21-GHz band, and this has become an important focus of our research. Broadcasting on such high frequencies has the problem of significant radio wave degradation, due to rain attenuation. Therefore, we are working on a variety of radio attenuation compensation schemes, including a phased array antenna technology, to heighten transmission gain in areas with rainfall. We have also been making observations and analyses of rain attenuation amounts, to compute the amount of compensation required. Additionally, large-capacity hard disk systems capable of recording many programs have become a reality. In line with this development, another ongoing research project involves a long block-length interleaving transmission scheme with the ability to compensate for rain attenuation by transmitting data dispersed over a long period.