High-Rate Modems for Wireless Data Communications

A NASA Small Business Innovation Research (SBIR) project has led to the development of high-rate (155.52-Mb/s) modems for use in high-quality wireless data communications. The research was directed toward conceiving innovative signal-processing techniques to reduce costs below those of conventional modems, implementing these techniques in a low-power complementary metal oxide semiconductor (CMOS) application-specific integrated-circuit (ASIC) modulator and a corresponding demodulator, and developing the necessary circuit boards (see figure) and control software. An additional goal of the research was to determine the maximum rate at which data can be transmitted through a standard 72-MHz-wide satellite-transponder channel.