A Low-Cost and Low-Power CMOS Receiver Front-End for MB-OFDM Ultra-Wideband Systems要该文全文，更换别的论文，或要中英文对照都可以找我Mahim Ranjan, Member, IEEE, and Lawrence E. Larson, Fellow, IEEE0Abstract—This paper presents an RF receiver front-end for MB-OFDM-based ultra-wideband (UWB) systems. The receiver occupies only 0.35 in a 0.18 CMOS process and consists of a low-noise amplifier, downconverter and a bandpass filter. There are no on-chip inductors and the receiver requires no off-chip matching components. The measured receiver gain is 21 dB, noise figure is less than 6.6 dB, input IIP3 is 5.6 dBm, and the receiver consumes 19.5 mA from a 2.3 V supply. The receivercovers all the MB-OFDM bands from 3.1 to 8 GHz.Index Terms—CMOS, distortion, OFDM, receiver, ultra wideband, UWB.I. INTRODUCTIONULTRA-WIDEBAND (UWB)multi-band orthogonal frequency-division multiplexing (MB-OFDM) systems have been proposed as an emerging solution to wireless communicationapplications requiring high data rates (up to 480 Mb/s) over short distances. In one proposed version [1], the carrier, with a bandwidth of 528 MHz, can hop to one of 14 channels（2904+528n,n=123…14）, divided into four groups of three channels and one group of two channels. This representative time-frequency interleaving for a Group 1-only systemis depicted in Fig. 1. Design of a receiver for such a systempresents many challenges due to the wide bandwidth of the RF front-end. However, to assure the widest possible adoption, RF portions of these systems should consume little DC power and die area, and be implemented in a standard CMOS process. These last requirements argue against the use of on-chip inductors wherever possible.Since theUWBfront-end intrinsically possesses a wide bandwidth, it is open to reception of undesired narrowband signals such as 802.11 a/b/g and the recently proposedWiMAX [2] systems, as shown in Fig. 2. Although OFDM systems are less susceptible to relatively narrowband jammers, nonlinearities in the receiver can result in jammer cross-modulation with wideband input signals, resulting in reduced signal-to-noise ratio (SNR) and a degradation in system performance [3]. In addition, received wideband signals (from other UWB transmitters) can intermodulate and the resulting products can land in a desired channel. Since the system is inherently wideband, harmonic distortion of a single unwanted UWB transmitter can also produce in-band distortion products and reduce the SNR. For the system to successfully operate in such a hostile environment, the linearity specifications of the receiver need to include these distortion effects. Fig. 1. Representative time-frequency interleaving pattern of a Group 1MB-OFDM signal [1]. Fig. 2. Representative spectrum at an MB-OFDM receiver antenna.This paper describes a UWB heterodyne receiver front-end that is designed to minimize the effects of wideband jammers from a variety of undesired sources [4]. In addition, the receiver is designed to minimize silicon area, so on-chip inductors are not employed. The receiver architecture is presented in Section II. Specifications for the receiver are derived in Section III. Detailed block design is presented in Sections IV–VI. Layout and packaging of the chip is discussed in Section VII. Measured results are presented in Section VIII, followed by a conclusion in Section IX.II. RECEIVER ARCHITECTUREWhen it comes to designing a low-power and low-cost receiver, the traditional choice is a direct conversion architecture. However, a direct conversion UWBreceiver, while attractive for power consumption and simplicity of its local oscillator (LO) scheme [5], [6], has a well-known problem of time-varying DC offset and sensitivity to narrowband jammers. A DC offset at the output of the receiver can degrade the SNR of the digitized baseband signal. In addition, it can introduce second-order distortion in the baseband signal, which further degrades the SNR. A Low-Cost and Low-Power CMOS Receiver Front-End for MB-OFDM Ultra-Wideband SystemsMahim Ranjan, Member, IEEE, and Lawrence E. Larson, Fellow, IEEE0Abstract—This paper presents an RF receiver front-end for MB-OFDM-based ultra-wideband (UWB) systems. The receiver occupies only 0.35 in a 0.18 CMOS process and consists of a low-noise amplifier, downconverter and a bandpass filter. There are no on-chip inductors and the receiver requires no off-chip matching components. The measured receiver gain is 21 dB, noise figure is less than 6.6 dB, input IIP3 is 5.6 dBm, and the receiver consumes 19.5 mA from a 2.3 V supply. The receivercovers all the MB-OFDM bands from 3.1 to 8 GHz.Index Terms—CMOS, distortion, OFDM, receiver, ultra wideband, UWB.I. INTRODUCTIONULTRA-WIDEBAND (UWB)multi-band orthogonal frequency-division multiplexing (MB-OFDM) systems have been proposed as an emerging solution to wireless communicationapplications requiring high data rates (up to 480 Mb/s) over short distances. In one proposed version [1], the carrier, with a bandwidth of 528 MHz, can hop to one of 14 channels（2904+528n,n=123…14）, divided into four groups of three channels and one group of two channels. This representative time-frequency interleaving for a Group 1-only systemis depicted in Fig. 1. Design of a receiver for such a systempresents many challenges due to the wide bandwidth of the RF front-end. However, to assure the widest possible adoption, RF portions of these systems should consume little DC power and die area, and be implemented in a standard CMOS process. These last requirements argue against the use of on-chip inductors wherever possible.Since theUWBfront-end intrinsically possesses a wide bandwidth, it is open to reception of undesired narrowband signals such as 802.11 a/b/g and the recently proposedWiMAX [2] systems, as shown in Fig. 2. Although OFDM systems are less susceptible to relatively narrowband jammers, nonlinearities in the receiver can result in jammer cross-modulation with wideband input signals, resulting in reduced signal-to-noise ratio (SNR) and a degradation in system performance [3]. In addition, received wideband signals (from other UWB transmitters) can intermodulate and the resulting products can land in a desired channel. Since the system is inherently wideband, harmonic distortion of a single unwanted UWB transmitter can also produce in-band distortion products and reduce the SNR. For the system to successfully operate in such a hostile environment, the linearity specifications of the receiver need to include these distortion effects. .........................
Based on the communication network Direct3D visual simulation engine design and implementation
the
Visual Simulation (Visual Simulation) is used to realize 3 d space information visualization technology, it has a realistic Simulation effect and convenient operation method, can well satisfy the new plane avionics system design requirements.
This paper designs and realizes an Direct3D based on the communication network visual simulation engine.
First, in this paper the characteristics of the visual simulation and the programming essentials Direct3D brief analysis of selection, and expounds the main reason for the Direct3D. Secondly, put forward the visual simulation software, the total design project of the simulation software program and the software module partition the working process of the analysis of the various modules, explore the main functions and the relations among them. And then, based on the communication network of Direct3D visual simulation is the key technology of engine are analyzed and the study, introduces solutions discrete event simulation, Direct3D resource management and animation optimization and the mouse control technology, the key technology of the method. Finally, this essay discusses the Direct3D based on the communication network visual simulation software realization method, and in a more complex switched communication network as an example, the visual simulation, and the performance of the program was tested
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我也有我自己翻译好了的，我可以先发原文给你，等你翻译完了，再探讨一下，我们翻译得怎么样。
