Bede Liu, Pioneer of Digital Signal Processing, Passes Away

On May 7, Bede Liu, an American scientist who made foundational contributions to digital signal processing (DSP), passed away at the age of 91. His work laid the groundwork for modern communication systems, multimedia, and consumer electronics, facilitating the transition from analog to digital technologies.

Liu taught at Princeton University for over 50 years and served as Chair of the Department of Electrical and Computer Engineering from 1994 to 1997. His research in the 1970s and 1980s became the basis for low-power digital processors that now enable cellular communications, streaming video, and internet-based interactions. In 2018, he was awarded the IEEE Jack S. Kilby Signal Processing Medal for his achievements.

Among Liu’s key contributions was the 1976 textbook *Digital Signal Processing: Theory, Design, and Implementation*, co-authored with Abe Peled, which became an industry standard. He also patented a method for parallel bit processing, significantly improving computational efficiency for audio and communication signals. His innovations reduced the cost and power consumption of electronics while advancing mobile and multimedia technologies.

In his later years, Liu focused on digital media protection. Working with his students, he identified vulnerabilities in digital watermarking technologies, helping to prevent unauthorized content distribution. His research in this area formed the basis of modern copyright protection systems in the film industry.

Liu mentored a generation of outstanding engineers, including Robert Kahn, one of the architects of the modern internet. For his contributions to science and education, he was elected to the U.S. National Academy of Engineering, the Chinese Academy of Sciences, and other prestigious institutions. Colleagues remembered him for his humility, enthusiasm, and ability to inspire students to pursue ambitious projects.