Shigeyuki Unagami

Title: Shigeyuki Unagami: Innovator in Signal Processing

Introduction

Shigeyuki Unagami is a notable inventor based in Atsugi, Japan, who has made significant contributions to the field of signal processing with a total of 19 patents to his name. His innovative work, particularly in echo cancellation and speech coding apparatus, exemplifies his expertise and commitment to advancing technology.

Latest Patents

Among his latest inventions is an **echo canceller**, which features an expected echo generating unit that creates an expected echo of a transmission signal. This device includes a frequency offset correction unit designed to detect phase errors between echoes in received signals and the expected echo. By correcting the frequency offset based on an estimated offset frequency derived from the phase error, the system effectively suppresses echoes in received signals. It's notable that frequency offset correction is performed after confirming the output from a near-end echo canceller has stabilized.

Another recent innovation is a **speech coding apparatus** that processes divided signal vectors using multipliers and prediction filters. This apparatus aims to obtain a reproduced speech signal by finding the smallest error between input and reproduced speech signals through various error detectors and evaluators. The use of a reduced code book with multiple corresponding components enhances the efficiency and accuracy of the speech coding process.

Career Highlights

Shigeyuki Unagami is currently employed at Fujitsu Corporation, where he applies his extensive knowledge of signal processing to develop innovative solutions that address modern communication challenges. His contributions have been critical in improving signal clarity and efficiency in various applications.

Collaborations

Throughout his career, Unagami has collaborated with notable colleagues such as Fumio Amano and Tomohiko Taniguchi. These partnerships have fostered a productive environment, leading to further innovations in their respective fields.

Conclusion

Shigeyuki Unagami's work in echo cancellation and speech processing showcases his dedication to pushing technological boundaries. As a prolific inventor with numerous patents, he continues to pave the way for advancements in communication technologies, benefiting industries and consumers alike.