专业英语题目.docVIP

2004级硕士研究生通信与信息系统 专业英语试题 写出下列英文缩写的全称： 1、MQAM 2、CSI 3、ISI 4、DFT 5、PSD 6、MSE 7、LOS 8、MSK 9、AWGN 10、PAPR 11、LDPC 12、UEP 13、AFD 14、MIMO 15、MLSE 16、IIR 17、LMS 18、DMT 19、OFDM 20、DARPA 21、WLAN 22、SINR 23、MAC 24、QoS 25、GSM 26、EDGE 27、PSTN 28、ADSL 29、IEEE 30、UWB Quadrature Amplitude Modulation Channel State Information Intersymbol interference Discrete Fourier transform Power spectral density Mean-square error Line of sight M shift keying Additive White Gaussian noise Peak to Average Power Ratio Low-Density Parity-Check Unequal error protect Average fade duration Multiple input multiple output Maximum likelihood sequence estimation Infinite impulse response Least mean square Discrete multitone Orthogonal frequency division multiplexing Defense advanced research projects agency Wireless local area network Signal to interference plus noise power ratio Medium access control Quality of service Globle system of mobile Enhanced data service of GSM Evolution Public switched telephone network 英译汉 If a single pulse is transmitted over a multipath channel the received signal will appear as a pulse train, with each pulse in the train corresponding to the LOS component or a distinct multipath component associated with a distinct scatterer or cluster of scatterers. An important characteristic of a multipath channel is the time delay spread it causes to the received signal. This delay spread equals the time delay between the arrival of the first received signal component (LOS or multipath) and the last received signal component associated with a single transmitted pulse. If the delay spread is small compared to the inverse of the signal bandwidth, then there is little time spreading in the received signal. However, when the delay spread is relatively large, there is significant time spreading of the received signal which can lead to