tailieunhanh - The next great telecom revolution phần 7

Trong thực tế, UWB truyền gây ra mối đe dọa rất ít can thiệp với tần số được cấp phép FCC bây giờ cho phép các công ty để hoạt động công nghệ UWB trong vòng 3-GHz 10-GHz phạm vi mà không có giấy phép phổ tần vô tuyến. Băng thông của tín hiệu UWB rộng tín hiệu năng lượng có sẵn để sử dụng ở tần số cao và thấp. | ASSET TRACKING 131 In fact UWB transmissions pose so little threat of interference with licensed frequencies that the FCC now allows companies to operate UWB technology within the 3-GHz to 10-GHz range without obtaining radio spectrum licenses. The bandwidth of UWB signals is so wide that signal energy is available for use at both high and low frequencies. The low-frequency content of UWB devices can penetrate solid structures says Buehrer an assistant professor of electrical and computer engineering and the project s principal investigator. That would make UWB highly useful for transmitting signals through buildings and other manmade and natural obstacles. Additionally the high-frequency content can detect the details of objects notes Buehrer. This capability combined with the technology s low power makes UWB radar an excellent surveillance tool. UWB also has the potential to become a significant military communications medium. Because of the low level of energy in UWB signals a military unit using the technology could communicate without a nearby enemy even perceiving that transmissions are taking place says Buehrer. UWB also has many commercial applications. For example most home wireless devices such as television remote controls are limited in the amount of data they can send and receive. UWB signals can achieve significantly higher data rates. As a result there s a potential for UWB wireless home computer networks wireless camera-to-computer downloads and wireless connections to thin-screen wall-mounted televisions. In the project s first phase Buehrer and his colleagues will develop models to show the characteristics of UWB-transmitted pulses and how the pulses will look to receivers. We ll discover what receivers see when they encounter UWB signals Buehrer says. The research team hopes to continue the project into a second phase during which they would use the models developed in the first phase to design UWB receivers. The project is funded by a 750 000 .