信噪比

Integrating trellis-coded modulation with threaded algebraic space–time block code, trellis-coded modulation space-time block code is presented, which has the advantage of full-diversity and small detection delay. Based on TCM pre-processing, the minimum distance between different codeword matrixes of the TCMST block code is maximized, so the average bit error rate of the TCMST block code is lower than that of the TAST block code at the same signal noise ratio.

TCMST分组码具有满发送分集度和检测延迟小等优点；由于采用了TCM预处理，使得不同TCMST分组码码字矩阵间的最小距离达到了最大化，因此在相同信噪比情况下，TCMST分组码具有比TAST分组码更低的平均误比特率。

If your pixel scale is much larger than the values quoted above, then the quality of the astrometry will suffer. If your pixel scale is too low for your local setup, then the signal-to-noise of the images may be low as each image is spread over a large number of pixels.

如果你的像素分辨率比上面要求大很多的话，那么可能导致天文测量的测量品质下降，但如果你的像素分辨率比上面要求的小很多，则会导致图片的信噪比下降，因为每个目标占据了过多的像素。

The main contributions in this area are summarized as follows,? The closed-form formula and its asymptotic form of system outageprobability are derived, through which it is shown that the outage probability decreased by a factor ofγ~(hereγdenotes the average SNR);? The closed-form formula of outage capacity is derived, through which weshow that 1 outage capacity increases with the increases of mean value of sytem SNR, and decreases with the increase of the variance of system average SNR; 2 in order to obtain higher outage capacity, the number of transmit antenna should be no more than that of receive antennas.?

特别的，针对多用户发送天线选择／最大比合并系统，主要贡献总结如下：·理论推导出中断概率的闭式解及其近似解，通过该近似解，可以得到中断概率以γ~的形式减少(这里γ是平均信噪比SNR)·推导出平均中断容量的闭式表达式，研究表明：1中断容量随着有效平均SNR的均值的增加而增加，随着有效平均SNR的方差的增大而减小；2为了获得更高的中断容量，发送天线的数目应当不大于接收天线的数目。

Adopt the generalized maximum likelihood radio test based on the Neyman-Pearson algorithm, to study two unresolved Rayleigh targets. And deduced the detection statistic which is chi-square random variable, which only need to know the conditional probability density functions of echo's measured amplitude, in-phase and quadrature of monopulse radio, but the signal-to-noise radio and the direction-off-arrival of any signal are unnecessary.

采用基于涅曼-皮尔逊准则的广义似然比检测，对不可分辨的两个瑞利目标进行了研究，推出了服从χ2分布的检验统计量，此方法只需要知道目标回波信号测量幅值的条件概率密度函数、单脉冲和差比值的同相和正交部分，而不需要任一目标信号的信噪比和DOA的先验知识。

To compare the image quality of the three sequences in two groups by One-Way ANOVA and T Test. The qualitative assessment standards include clarity, artifacts, signal uniformity, the conspicuity of enhanced vein and the observable grade of intrahepatic venous branchs. The quantitative assessment standards include SNR and CNR of intrahepatic portal vein and hepatic veins. Furthermore, the anatomy and variations of the intrahepatic portal vein and hepatic veins are statistical analysed.

通过方差分析和T检验分别对A、B组三个序列的图像质量进行比较，评定标准包括清晰度、伪影、信号均匀性、静脉强化程度及肝内静脉分支显示级数等定性指标和肝内门静脉、肝静脉的SNR(Signal-Noise Ratio，信噪比)及CNR(Contrast-Noise Ratio，对比度噪声比)等定量指标。

Actually ,signals are processed from low frequency domain to high one by modulation firstly and alternating current amplification secondly.It can also improve anti-interference抗干扰 ability of circuit and signal to noise ratio of signals.

实际中往往采用更有效的先调制而后交流放大，将信号从低频区推移到高频区，也可以提高电路的抗干扰能力和信实际中往往采用更有效的先调制而后交流放大，将信号从低频区推移到高频区，号的信噪比。

Also, it is deduced from the conclusions of maximum likelihood estimator that the performance of estimators is independent on source number if the number of snapshots used in estimator is large enough.

证明了它们在低信噪比情况下仍具有渐近无偏的估计性能；另外，利用最大似然估计器的相关结论，证明了在快拍数足够大的情况下，估计器的估计性能与信源数目的多少无关。

The block-based fractal image compression method has a low compression ratio, so simple region-based fractal image compression is introduced, then the competitive region-based fractal image compression method is presented. The experimental results show that the compression ratio is effectively improved at a similar PSNR value.

由于基于块的分形图像压缩方法的压缩比不高，对此进行改进，先介绍简单的基于区域的分形图像压缩，然后提出基于区域的竞争分形图像压缩算法，并进行实验，实验结果表明，该方法在保持一定的信噪比的情况下，有效的提高了压缩比。

In consideration of the in-pulse phase modulation and Doppler frequency rate-of-change's subtleness, a fast and accurate algorithm is proposed. The influence to parameter estimation with phase modulation is dismissed by time domain correlation between neighboring pulses. Signal noise ratio is increased by frequency domain accumulation.

该文针对信号脉内相位调制和多普勒频率变化率信息非常微弱的特点，提出了一种快速高精度估计算法，通过相邻脉冲间的时域相关消除了相位调制对参数估计的影响，频域积累增强了信噪比，利用脉冲间的相参特性进行频谱相关消除了相位模糊，并放大了多普勒频率变化率信息。

The experiment shows that CSELF is potentially valuable for earthquake research and prediction. It is also found that the recorded electric and magnetic component amplitude of CSELF signal varies depending on the distance and azimuth of the observatories relative to the transmitter. These amplitudes decline with increasing distance between observatory and transmitter faster within some space extent than those outside the extent. It may be easier for magnetic components to have higher ratio of signal to noise than for electric component.

试验还发现，各地震台站和流动测点观测的CSELF信号的强度，与台站或者测量的电、磁场分量相对于发射源的距离、方位有明显的关系；发现在离开发射源的相对近区，场强随距离的衰减，比在相对远区更快；发现接收磁场信号比电场信号较易获得更高信噪比的数据。

They weren't aggressive, but I yelled and threw a rock in their direction to get them off the trail and away from me, just in case.

他们没有侵略性，但我大喊，并在他们的方向扔石头让他们过的线索，远离我，以防万一。

In slot 2 in your bag put wrapping paper, quantity does not matter in this case.

在你的书包里槽2把包装纸、数量无关紧要。