Tham khảo tài liệu 'ultra wideband communications novel trends system, architecture and implementation part 5', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 6 Ultra-Wideband RF Transceiver Design in CMOS Technology Lingli Xia1 2 Changhui Hu1 Yumei Huang2 Zhiliang Hong2 and Patrick. Y. Chiang1 1 Oregon State University Corvallis Oregon 2ĩudan University Shanghai 2USA 2China 1. Introduction UWB Ultra-Wideband is one of the WPAN Wireless Personal Area Network Technologies its main applications include imaging systems vehicular radar systems and communications and measurement systems. Ever since the FCC released unlicensed spectrum of GHz for UWB application in 2002 UWB has received significant interest from both industry and academia. Comparing with traditional narrowband WPANs . Bluetooth Zigbee etc. the most significant characteristics of UWB are ultra-wide bandwidth GHz and low emitted spectrum density dBm MHz . According to Shannon-Hartley theorem Wikipedia 2010 through an AWGN Additive white Gaussian Noise channel the maximum rate of clean or arbitrarily low bit error rate data is limited to p I c BW log21 1 N SBW BW ỉoẽ2 1 SNR 1 where c is the channel capacity BW is the channel bandwidth Ps is the average power of the received signal No is the noise spectral density. As can be seen from 1 channel capacity increases linearly with bandwidth but only logarithmically with SNR. With a wide bandwidth high data rate can be achieved with a low transmitted power. Mutli-Band OFDM MB-OFDM and Direct-Sequence UWB DS-UWB are two main proposals for UWB systems each gained multiple supports from industry. Due to incompatible of these two proposals UWB technology faces huge difficulties in commercialization. On the other hand Impulse Radio UWB IR-UWB has been a hot research area in academia because of its low complexity and low power. In the following we first introduce previous works on different kinds of UWB RF transceiver architectures including MB-OFDM UWB DS-UWB and IR-UWB transceivers. Both advantages and disadvantages of these architectures are thoroughly discussed in section 2. Section 3 presents a .
