查询词典 signal noise ratio

Using minimum mean square error criterion at receiver, the mean square error matrix submits to inverse wishart distribution at high signal to noise ratio.

当接收端使用最小均方误差准则检测时，检测后的MSE矩阵在高信噪比下服从逆wishart分布。

Through wiping off yawp of prestack and poststack, we can increase signal-to-noise ratio of data.

有针对性的使用叠前去噪和叠后去噪技术，提高了剖面的信噪比。

CLIA using acridinium ester derivatives as chemiluminescent label has advantages of low background,high signal-to-noise ratio,no need of catalyst and simple luminescence system.

以吖啶酯衍生物为发光标记物的CLIA的特点是：标记简单、标记物稳定、不需要催化剂、自然本底低、受外界干扰因素少、信噪比高、发光体系简单等。

Chemiluminescent immunoassay is one of the advanced immunoassay ofnon-radioisotopic immunoassay because of its high sensitivity, wide dynamic range,high accuracy, stable labeled protein, full automation and extensive application field.CLIA using acridinium ester derivatives as chemiluminescent label has advantages oflow background, high signal-to-noise ratio, no need of catalyst and simpleluminescence system. Different aspects associating the DMAE·NHS-based CLIA were studied in thisthesis, including synthesis of acridinium ester, chemiluminescentcharacteristics of DMAE·NHS, labelling antibody or streptavidin with DMAE·NHS,two-site sandwich chemiluminescent immunoassay for TSH, two-sitesandwich chemiluminescent immunoassay involved biotin-streptavidinsystem for TSH, and competitive chemiluminescent immunoassay usingbiotin-streptavidin system for TT〓. The desired acridinium ester, DMAE·NHS, was synthesized according to thereference method with some modifications. The products were identified by IR, NMR,MS and elemental analysis. In our method, KOH was used in place of NaOH tosynthesize benzyl ester of 3,5-dimethyl-4-hydroxybenzoic acid,2',6'-dimethyl-4'-(n-succinimidyloxycarbonyl) phenyl-acridinium-9-carboxylate waspurified on a silica gel column with chloroform/ethylacetate(4:1, v/v) as eluent andfurther purified by triturating with hexane/acetone(2:1, v/v).

DMAE·NHS的合成是本论文的关键和难点，我们对文献方法进行改进：文献方法用氢氧化钠与3，5-二甲基-4-羟基苯甲酸反应制得3，5-二甲基-4-羟基苯甲酸钠，再用3，5-二甲基-4-羟基苯甲酸钠与苄氯作用制备3，5-二甲基-4-羟基苯甲酸苄酯，我们用氢氧化钾代替氢氧化钠，使合成取得成功；在合成2'，6'-二甲基-4'-苯基-吖啶-9-甲酸酯时，文献方法对粗产品进行两次硅胶柱层析纯化，第一次柱层析用氯仿／乙酸乙酯(4∶1，V∶V)作溶剂和淋洗剂，第二次柱层析用己烷／丙酮(2∶1，V∶V)作溶剂和淋洗剂，按照文献方法得到的不是所需要的化合物，我们只进行第一次柱层析纯化，然后用己烷／丙酮(2∶1，V∶V)进行研磨，过滤，洗涤，除去溶于己烷／丙酮(2∶1，V∶V)的部分，得到所需要的产品。

The experiments show that the proposed image compression and denoising method can significantly outperform those that are based on Bandelet or Contourlet transform in visual quality for the images with abundant edges and texture, and the peak signal to noise ratio is also increased by more than 0.1 dB.

实验结果表明，对于纹理和边缘丰富的图像，所提出的图像压缩和去噪方法在视觉质量上明显优于基于Bandelet或Contourlet变换的方法，峰值信噪比也提高了0.1dB以上。

The signal-to-noise ratio averagely enhances about 2. 7dB under dichotic listening condition than diotic listening condition.

双耳有差别听闻与双耳无差别听闻相比，其信噪比平均提高约为2.7dB。

It was observed that the fourth method can achieve higher diffractive efficiency and signal-to-noise ratio.

再者，第四种量化方法可较达到较高的效率也可较达到较高的讯杂比。

To solve the problems less valid data in thermal infrared imager, uneasy dipartite corrosion area in image and lower the signal to noise ratio which happened in detection of structure parts hidden corrosion by thermal wave imaging, the improved PCA based on the wavelet was presented.

针对飞机结构隐藏腐蚀热波成像检测中出现的热像仪中有用数据较少、图像序列中腐蚀区域与非腐蚀区域对比不明显、信噪比较低等问题，提出了基于小波变换的改进PCA算法。

There was signficant Differences in contrast-to-noise ratio of the experiment group and the control group (11.50±2.32 vs 2.71±0.86, P＜0.01). The same results were derived from 30 rain to 1 hafter contrast agent being injected in distal to heart part of the injured vessel, and the signal decreased 24 h later.

另从犬损伤部位远心端注射对比剂30 min至1 h，也显示了上述成像效果；2 h至4 h血栓信号由明显上升渐见趋缓，延迟24 h信号强度减弱，实验组CNR值与对照组间差异也有统计学意义(10.40±2.15比1.93±0.57，P＜0.01)。

In the intersatellite coherent optical communication, the vibration of a satellite will lead to a pointing error of transmitting and receiving antennas, which will decrease the signal-to-noise ratio and increase the bit error rate. In this paper, the Rayleigh distribution is taken as the pointing error model caused by satellite vibration, and PSK homodyne communication scheme is used as an example to analyze the influence of the satellite vibration on the system instantaneous BER and average BER. The simulation calculation result of BER is given.

针对星间相干激光通信中卫星平台的振动造成发射天线和接收天线的瞄准角误差，使系统信号信噪比下降，误码率增加，该文以瑞利分布作为振动造成的瞄准角误差模型，结合高斯本振光和艾里信号光外差检测模型，以PSK零差通信体制为例分析卫星振动对系统的瞬时误码率和平均误码率的影响，给出误码率仿真计算结果。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。