Katsuya Shimomura

Title: Katsuya Shimomura: Innovator in Frequency Synthesis and Gain Circuitry

Introduction

Katsuya Shimomura is a notable inventor based in Kasugai, Japan. He has made significant contributions to the field of electronics, particularly in the development of frequency synthesizers and variable gain circuits. With a total of 3 patents to his name, Shimomura continues to push the boundaries of innovation in his field.

Latest Patents

One of Shimomura's latest inventions is a PLL frequency synthesizer. This synthesizer outputs signals with different frequencies, utilizing voltage-controlled oscillators that adjust their oscillation frequencies based on control voltages. The design includes a first switch to select one of the signals, a frequency divider to generate a frequency-divided signal, and a phase comparator to determine the phase difference between the frequency-divided signal and a reference signal. Additionally, a second switch connects to low-pass filters, each tailored for one of the voltage-controlled oscillators, which convert the phase difference into control voltages. A controller manages the operation of the switches and frequency divider, ensuring continuous output of stable signals.

Another significant patent is a variable gain circuit with improved gain response. This circuit amplifies an input signal with a gain that varies according to a control voltage. It features a first amplifier with a gain proportional to the control voltage in a lower range and a second amplifier that maintains a constant gain in a lower range while being proportional in a higher range. The second amplifier is linked to the first via coupling capacitors, making it suitable for use in CDMA telephone transmitters.

Career Highlights

Katsuya Shimomura is currently employed at Fujitsu Corporation, where he applies his expertise in electronics to develop innovative solutions. His work has been instrumental in advancing technologies that are crucial for modern communication systems.

Collaborations

Throughout his career, Shimomura has collaborated with talented individuals such as Takehiro Akiyama and Kouzi Takekawa. These collaborations have fostered an environment of creativity and innovation, leading to the development of groundbreaking technologies.

Conclusion

Katsuya Shimomura is a distinguished inventor whose work in frequency synthesis and variable gain circuitry has made a significant impact in the field of electronics. His patents reflect a commitment to innovation and excellence, contributing to advancements in communication technology.