查询词典 SNR

For this class of estimators, several SNR estimation algorithms have been investigated.

同时对于这类估计方法，我们对几种信噪比估计算法进行了研究。

The return signal from propeller aircraft and jet plane in different SNR is simulated based on the statistic model of the disturbed clutter,a...

根据给定的目标建模算法和干扰反射杂波模型，模拟了不同信杂比下螺旋桨飞机和喷气式飞机的雷达回波，仿真结果表明，这两种目标具有不同的频谱结构，证明了给出的模型是有效的，为雷达系统提供了实用的回波仿真信号。

The return signal from propeller aircraft and jet plane in different SNR is simulated based on the statistic model of the disturbed clutter, and the calculated results are analyzed and compared. The results show that the model presented is valid and provides a useful simulated signal for the radar system.

根据给定的目标建模算法和干扰反射杂波模型，模拟了不同信杂比下螺旋桨飞机和喷气式飞机的雷达回波，仿真结果表明，这两种目标具有不同的频谱结构，证明了给出的模型是有效的，为雷达系统提供了实用的回波仿真信号。

The calculation result shows that it is better to select the waveband of 0.5μm～0.9μm than that of 0.5μm～0.8μm considering entrance-pupil radiation intensity and SNR of the remote sensor.

计算结果表明：遥感器光谱波段选择0.5μm～0.9μm波段，在入瞳辐射亮度和信噪比等方面优于选择0.5μm～0.8μm波段。

The linewidth of laser is less than 10 kHz, measured by the delayed self-heterodyne method with 10 km monomode fiber. SNR is about 56 dB.

采用10km单模光纤延迟线进行了延迟自外差线宽测量，得到光纤激光器的3dB线宽小于10kHz。

Increasing the input noise may increase the signal-to-noise ratio of the output response V(t within the element's parameter region indicating that the periodic components of V increase as the input noise increases. The relationsip between the variation of the SNR of the V curve and the noise is similar to the that of the resonance.

结果表明：在一定的条件下，增大输入噪声的值不仅不降低输出响应信噪比；反而迅速增加输出响应的信噪比，使输出响应中周期信号的分量反而加强，而且输出响应的信噪比对于输入噪声的变化具有&共振&形状的曲线。

Simulations show the effectiveness and feasibility to reduce the loss of surds and to enhance the SNR (Signal-to-noise Ratio).

该方法在很大程度上抑制了噪声，又减少了语音段清音的损失，提高了信噪比。仿真结果表明了该方法的可行性和有效性。

We design an efficient measurement to estimate the skywave delays, and get the arrival time of groundwave and skywave separately in poor SNR.

该文设计出一种估计天波延迟的高效处理方法，在低信噪比条件下分离出了地波和天波的到达时刻。

It was shown that the SNR of the RADS could be improved by using a microwave cavity with proper microwave field mode and high microwave filling factor, a rubidium spectrum lamp with high spectrum purity and a separated isotope filtering scheme in the physics package design. The performance of the rubidium atomic frequency standard could be improved by taking all these factors into consideration.

本文分析了微波腔的结构、铷光谱灯的光谱纯度和同位素滤光方案对信噪比的影响，指出采用模式优越、微波填充因子大的微波腔，光谱纯度高的铷光谱灯，用分离滤光方法进行同位素滤光，可以提高铷原子鉴频信号的信噪比，从而使铷频标的稳定度指标得到进一步改善。

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。

Liapunov—Schmidt method is one of the most important method in the bifurcation theory.

Liapunov—Schmidt方法是分叉理论的最重要方法之一。

Be courteous -- even when people are most discourteous to you .

要有礼貌──即使当別人对你最不礼貌的时候。