Matsuzawa & Okada Laboratory

Research

Our Aims and Perspectives

It evolved to the digital technique now though the basis of electronic equipments was an analog technology before. As a result, not only personal computers but also "Digital consumer electronics" for example DVD, digital TV, digital still camera, flat panel display and so on dominated in the world. Furthermore, a digital network, for example Internet, Wireless LAN, and the cellular phone and so on will be expected to spread. Aggravated problems of the signal integrity, the noise radiation, and power consumption, etc. are at these equipments. It is necessary to use a sophisticated analog technology, even if the digital techniques are used for these. Therefore, the technology that mixes the digital technique with the analog technique is desired currently. Namely, the "mixed signal system LSI" is the most important key technology in electronics. Our researches focus on the high performance mixed signal system LSI design.

Research Topics

"The Implementation of Multi-bands Multi-standards Wireless Systems LSI."

Multi-bands multi-standards wireless systems that based on software defined radio techniques are demanded more and more in the future. To meet such requirements, the high performance A/D converters and digital RF techniques are receiving much attention as important elements. These techniques are expected to become key technnology at not only wireless systems but also wireless sensor networks, high performance digital networks and Digital Recording Systems etc. Furthermore, these techniques assure to provide some unexpected evolution in the world. To implement these concepts, our laboratory develops following elements.

  1. The Development of High-performance CMOS Analog to Digital Converters
  2. Wideband RF Circtuits
  3. Digital RF Techniques for Wireless Systems

The Development of High-performance CMOS Analog to Digital Converters

A recent trend toward a large system integration on a LSI. The biggest problems associated with the high density integration is higher speed operation, power dissipation and low voltage circuit design. To meet such requirements as the wide bandwidth operations under the low supply voltage, A/D converters are receiving much attention as important elements.


Wideband RF Circuits

underconstruction


Digital RF Techniques for Wireless Systems

Multi-bands multi-standards wireless systems should be based on software defined radio techniques. Meanwhile, the analog technology has been still used in a lot of wireless RF circuits that operate over GHz. Herein key features of digital RF techniques that we propose are able to reduce analog counterparts, and to have the excellent interface with software. However, the design techniques of digital RF are not yet established. Therefore, to exploit such potential of digital RF techniques, the diagram shown in Fig. 3 is investigated in our laboratory. We especially take up the elements as follows. The sampling mixer that has filter function. The digital synthesizer that can adjust to multi-band, and achieves high-speed frequency change. By combining with high-performance CMOS A/D converter techniques that can adjust characteristics, it is possible to produce that wireless system LSI and wireless sensor network LSI that responds to multi-band multi-standard.