信噪比

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。

A phase-locked amplifier is used to improve the signal-to-noise ratio of photoelectricity signal, and a computer is utilized to incept the sampling sig...

用锁相放大器来提高光电信号的信噪比，信号被快速采样后由接口电路输入计算机，自动给出所测单模光纤的模场半径。

The Pick-pick Signal Noise Ratio PSNR or Mean Square Error MSE does not conform to subjective psychological sensation, while subjective assessment is usually inexactly and has subjectivity.

通常使用的峰—峰信噪比或均方误差与主观感觉并不相符，而主观评价又存在主观性和不确定性，其结果往往因人而异。

At last,this paper analyzed the influence of the inversive receiver to the chracteristic of the clutter and the ratio of signal power and the noise power ,discussed the effective detection of target signal in correlated clutter,and then put forward a new method naming multi-periods shift accumulation for detecting moving target when not knowing the exact movement parameter.

最后，本文分析了倒置接收对目标回波信噪比及杂波特性的影响，讨论了在相关杂波区对回波信号有效检测的方法。针对如何在弹目相对运动参数未知的条件下对高速运动目标进行积累检测这一问题，提出了一种多周期移位积累的新方法。

Conventional filtering is incapable of removing noises and improving the signal-to-noise ratio of microseismic record.

而常规的滤波方法在消除噪声，提高信噪比方面难以胜任。

We obtain a optical image amplification with high gain factor of 1583 in doped lithium niobate crystals.

并在掺杂铌酸锂晶体中获得了高信噪比，信号光增益高达1583倍的光像放大。

Some methods to improve the system's output SNR by coherent or noncoherent operating are also discussed.

最后讨论了用相干或非相干处理来改善系统输出信噪比的方法。

Differential unitary space-time modulation in conjunction with noncoherent detection avoids MIMO channel estimation and is suitable for fast fading channels.

当采用较高电平调制时，在相同信噪比范围内，所提算法在几乎不损失误码率性能的同时，较原算法节省大于30%的比较次数。

Under the condition of varying , the ratio between noise levels in local sensors, this dissertation derives the analytic expression of performance of the centralized OS-CFAR detection for and local signal-to-noise ratio in nonhomogenous background.

本文在局部传感器背景噪声功率水平间的相对比例系数变化情况下，推导出了集中式 OS-CFAR 检测在且局部观测信噪比条件下在非均匀杂波背景中检测性能的解析表达式。

The digital spectra and SNR of nonuniformly sampled signals is analyzed by utilizing Fourier transform technique.

利用付氏变换的分析方法对这类非均匀取样信号的数字谱结构及信噪比进行了分析。

Finally, according to market conditions and market products this article paper analyzes the trends in the development of camera technology, and designs a color night vision camera.

最后根据市场情况和市面上产品的情况分析了摄像机技术的发展趋势，并设计了一款彩色夜视摄像机。

Only person height weeds and the fierce looks stone idles were there.

只有半人深的荒草和龇牙咧嘴的神像。