衰落中的

SRC in SDR is also discussed, and two improved structures of CIC filter are presented. The first one is a CIC decimation filter based on polyphase structure and partially sharpening technique, which is suitable for the situation where the requirements in passband attenuation is not very high while the requirements in alias suppression and operating speed are relatively high. The other one is an improved CIC-Rotated Sinc decimator which possesses improved frequency response, low operating rate and low cost in hardware as well.

研究了软件无线电中的采样率转换技术，给出两种改进的CIC滤波器结构；(1)基于多相结构和部分尖锐化的CIC抽取滤波器，该结构适用于通带衰落要求不是很高，混迭抑制和滤波速度的要求相对较高的场合(2)一种改进CIC-Rotated Sinc抽取滤波器，该结构在获得好的通阻带特性的前提下，一方面降低了整个CIC滤波器结构的工作速率，另一方面尽可能地降低硬件实现的复杂度。

The channel property of frequency selective fading and Doppler frequency shift are the biggest challenge to the broadband mobile communication service.

在信道的衰落特性中，对宽带无线移动业务影响最大的是多径衰落和多普勒频移。

Since its ancestor,Sushen,Manchu had the custom of believing in Shamanism.While with the development of feudalization of Manchu society,the conflict between the Shamanism and feudal culture,feudal governance became severe,which destined its unchangeable fate of declination.

满族自其先世肃慎以来，囿于低下的生产力发展水平和原始采猎的生产生活方式，皆有信奉萨满教的风俗，但到努尔哈赤、皇太极统治时期，随着生产的发展和社会的进步，以及民族的迁徙及中原文化的冲击，萨满教失去长期以来在满民族意识形态领域中的统治地位而逐渐走向衰落。

Firstly, the Signal Noise Ratio characteristic of matched filter despread symbol and the distribution of coherent phase estimation error are derived. Secondly, the exact integration formula of BER for fading channel is presented, moreover, by using the Maclaurin series expansion of MPSK conditional Symbol Error Rate, the simplified BER approximations for BPSK and QPSK are derived over AWGN, Nakagami-m fading and Rayleigh fading channel.

首先推导了匹配滤波解扩符号的信噪比特性和相干相位估计误差的分布；然后给出了衰落信道中误比特率的精确积分式，并利用MPSK条件误符号率的麦克劳林级数形式，推导了AWGN，Nakagami-m衰落和瑞利衰落信道中BPSK，QPSK误比特率的简化逼近式。

In frequency selective fading channels, different channel has different fading, that is to say, different channel has different transmission quality.

在频率选择性衰落信道中，不同的子信道受到不同的衰落，也就是说有不同的传输质量。

Inherent inter-symbol and inter-carrier interference elimination ability of orthogonal frequency division multiplexing system attribute to its cyclic prefix. But the case of multipath fading channels whose the channel impulse response length exceeds the duration of cyclic prefix causes intersymbol interference and intercarrier interference, which may degrade system performance severely.

正交频分复用系统中的循环前缀具有一定的抗码间干扰和子载波间干扰的能力，但是当多径衰落信道的最大信道脉冲响应长度超过了循环前缀长度时，OFDM系统的性能将会严重下降。

The simulation result indicated that, TCM coded system get bigger gain than uncoded system in the high signal to noise ratio.

通常为了克服多经衰落的影响，在中高速数据传输系统中，一般都采用自适应信号处理技术和纠错编码技术。

The paper investigates both block-type pilot linear minimum mean square error algorithm and IEEE802.16 OFDM channel estimation analysis. Simulation results confirm the block-type pilot structure is more suitable for IEEE802.16 system. An optimal pilot setting algorithm, based on space frequency domain, is explored and the pilot chart is presented. The proposed algorithm finds its application in MIMO-OFDM. Simulation results show the algorithm presents a good approximation to the perfect channel state information curve, with about 2dB difference in SNR. The simulation results also demonstrate the algorithm achieves fairly high stability in the environment of fast fading, performance of the proposed algorithm is better that of pilot training channel estimation.3. Taking into account the characteristics of IEEE802.16 OFDM system, OFDM system simulation platform is constructed in Matlab, exploiting simulink as a tool. OFDM modulation and demodulation simulation system are configured on LabVIEW platform. All the system signal processing is simulated, including defining system parameters, designing modulation model, and verifying all the proposed algorithms under different environments, such as white Gaussian noise, multi-path fading, with or without guard interval etc. Bit error performance is evaluated. The research provides valid theoretical basis for practical OFDM system performance evaluation.4. Taking advantage of software radio, the paper designs a hardware platform with both 256-IFFT/FFT and 512-IFFT/FFT OFDM schemes co-existing in one platform. You can predetermine one from the two schemes to carry out almost the same model function with different system performance and parameter setting.5. Referring to IEEE802.16 standard, the paper proposes a design method for generating signals and frames suitable for laboratory investigations implemented in laboratory environment.6. Based on 6701evm digital evaluation card, combined with analogy front-end, the paper designs a DSP software model to deal with baseband signal processing. An overall OFDM scheme, with modulation and demodulation function, is accomplished.

讨论分析了MIMO-OFDM中一种基于空频域的最优导频设置算法，给出了导频图案，通过仿真实验表明，该算法与理想的信道状态信息曲线非常接近，信噪比差距约在2dB左右，并且在快衰落条件下具有较好的稳定性，其性能要优于基于前导训练的信道估计方法。3、根据IEEE802.16OFDM系统特点，论文分别在Matlab中应用Simulink工具构建OFDM系统仿真平台、在LabVIEW平台上实现了OFDM调制解调仿真系统，模拟了整个系统的信号流程，进行了OFDM仿真系统参数的选择和调制模块的仿真设计、论证各算法性能，并根据各种不同的条件：例如高斯噪声、多径衰落、有无保护间隔等，对系统的误码特性进行了评估，为正确评价实际OFDM系统的性能提供了有效的理论依据。4、论文以软件无线电思想作为指导，提出了以256点IFFT／FFT为核心和以512点IFFT／FFT为核心的两种OFDM算法模式并存于同一个硬件平台、且可预选的方案，它们在参数选取和性能指标上有所差异，均实现了相似的模块和功能。5、论文参考IEEE 802.16无线网络标准的参数设置，针对本设计系统的应用环境和系统硬件的性能速率，提出了一种应用于实验室环境的信号结构、帧格式等参数设计。6、论文基于TI公司的6701evm数字评估板卡，结合模拟前端搭建数字中频平台，设计了基带处理的DSP软件模块并进行系统调试，基本实现了一套完整的OFDM调制解调方案。

Simulations in flat-faded application scenarios show that, the subspace method can achieve the same diversity order with the coherent reception, and outperforms the noncoherent decoder in existence with multiple successive space-time codes being decoded jointly.

平坦衰落信道环境中的仿真表明，子空间方法能够实现和相关接收相同的分集增益；当多个连续的空时码联合解码时，其性能优于现有的非相关解码方法。

With the social development in the seventeenth-century Holland,the close tie between the social context of the interior paintings and the Dutchmen shortens the distance between the art and the reality——a more lively and unique cultural relationship between the art of the interior paintings and the everyday life of the average Dutchmen.

这是一个对于对象和尊严的思考不再支配绘画艺术的时代，宗教题材被贬低到次要位置，即便是涉及这类题材的地方，也只是作为叙事中的事件，而不再是作为事实来处理，寓言和象征的人物衰落了。

Since historical times,England ,where the early inhabitants were Celts, has been conquered three times .

从有历史以来，英国，在此地早期居住的是凯尔特人，已经被征服了三次。

Bluetooth OBEX File Transfer Enables the sending and receiving of files on your phone via Bluetooth.

蓝牙OBEX文件移动允许经过蓝牙传送和接受文件。。。。