查询词典 frequency modulation

Used mainly engaged in Communications equipment Products: Network Analyzer, integrated tester, spectrum analyzer, noise figure testers, receiver, telephone tester, high, low-frequency signal source, audio and video signal source, high, low-frequency oscilloscope, modulation device, video analysis detector.

主要经营二手通信仪器产品：网络分析仪，综合测试仪，频谱分析仪，噪声系数测试仪，接收机，电话测试仪，高、低频信号源，音、视频信号源，高、低频示波器，调制仪，视频分析仪等。

The introduction of some products are as follows: First, Taiwan's electronic devices Aosta Product:(self-produced self-marketing) program-controlled voltage insulation tester, grounding resistance, leakage current, micro-resistance tester, electrical parameters of the test Transformer parameters meter, insulation resistance tester, electronic load, on-machine, cable tester, variable frequency power supply, LCR Bridge, frequency meter, mV table, the standard signal generator, oscilloscope, signal generator, signal generator, digital multimeter, distortion device, before shaking device, spectrum analyzer, capacitance meter, inductance meter, modulation device, Sweep Signal Generator, Telephone Analyzer, Calibrator Table III, EMC Electric Tester, regulated power supply and so on.

现将部分产品介绍如下：程控耐压绝缘测试仪、接地电阻、泄漏电流、微电阻测试仪、电参数测试变压器参数测量仪、绝缘电阻测试仪、电子负载、导通机、排线测试仪、变频电源、LCR电桥、频率计、毫伏表、标准信号源、示波器、信号发生器、信号源、数字万用表、失真仪、抖摆仪、频谱分析仪、电容测量仪、电感测量仪、调制度仪、扫频信号发生器、电话分析仪、三用表校准仪、EMC电测仪、稳压电源等。

Based on the time-frequency analysis (continuous wavelet transform and short time Fourier transform), the arithmetic uses the modulus maximum characteristic on the phase scale and carry frequency scale to recognize phase modulation rule of signal. So without whole wavelet coefficient the signal mathematics model can be obtained quickly. It provides well condition for application of arithmetic in practice.

该算法基于信号的时频分析（小波分析和短时傅里叶变换），利用小波变换的相位尺度和载波尺度的模极大值特征辨识信号的相位调制规律，因而在无需计算全部小波系数的情况下，可快速地获得信号的数学模型，为算法在实际中的应用提供了良好的条件。

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。

Amplitude modulation: The form of modulation.

调幅：调制的一种形式。

The performance of 2-level pulse amplitude modulation and analogue pulse width modulation system based on self-error-correction code was analyzed.

基于自纠错码的二级脉冲幅度调制与脉冲宽度调制光纤传输技术，对系统中的接收机灵敏度进行了分析。

The general analytic expression of the space vector modulation wave was induced and the continuous and discontinuous modulation mode were unified by the analytic expression.

文中归纳出空间矢量调制调制波的通用解析表达式，并由此将连续调制和不连续调制统一起来。

First we depicted one theoretical model of LCoS device, and then working modes of LCoS used as phase-only SLM were selected and optimized by varied the twist angle of liquid crystals and polarized angle due to parameter space method, two working modes, which are suitable to apply LCoS as phase-only SLM, were found, that is (0°, 0°) and (0°, 52°). Theoretical study also showed that the (0°,52°) could be used as a compound device, it behaved property of intensity modulation if a working point was selected appropriately and it behaved property of phase modulation when another wording point was selected. At the same time, this two working modes were studied detailed by extended Jones matrix method.

首先建立了LCoS器件的理论模型，并采用参数空间的方法通过改变液晶的扭曲角度和偏振片的起偏角度选择和优化了LCoS器件用作相位调制的合适的工作模式，找到了两种比较合适的作为相位调制的工作模式----(0°，0°)和(0°，52°)配置。

The results show the temporal pulse shape modulation is affected by the broadening factor and the delay time, as spectrum modulation is only affected by the delay time, and the intensity factor changes similarly with the cosine function of the phase factor.

研究结果表明，时间调制与基元脉冲的展宽量及相邻脉冲之间的延迟时间有关，光谱调制只与相邻脉冲之间的延迟时间有关，而强度的演化则与相位因子的余弦函数演化具有一定的相似性。

In this paper,a design method of two dimensional Linear Phase Nearly Perfect Reconstruction filter banks based on a new class of cosine modulation systems is presented,which can be described as follow: firstly,the Parks-McClellan algorithm is adopted for designing the prototype filter,then by employing cosine modulation,a series of analysis and synthesis filters can be obtained,accordingly a one-dimensional LP-NPR filter banks can be constructed;Secondly,cascading two one-dimensional LP-NPR filter banks in the form of tree structure and using the unimodular transformation,a two dimensional nonseparable LP-NPR filter banks can be obtained.

提出了一种基于一类新余弦调制系统的二维线性相位-近似完全重构滤波器组的设计方法，设计过程分为两个步骤：首先采用Parks-McClellan算法来计原型滤波器，再经过余弦调制能到一系列的线性相位分析和综合滤波器，从而可以构造一维LP-NPR滤波器组；然后利用树状结构来结合两个一维LP-NPR滤波器组，并运用单位模变换，可以得到二维不可分离LP-NPR滤波器组。

The dissecting of samples in group2 were difficult. The root of pulmonary artery and ascending aorta failed to be unfolded because fibrous tissue was tough, right and left fibrous trigone were too firm to be solved by hand. Cardiac muscle fibers couldn't be stripped along myofibrillar trajectory since they were prone to break because of their friability.

组2的心脏解剖困难，表现为纤维组织坚韧，游离肺动脉非常困难；徒手无法松解左、右纤维三角，肺动脉和主动脉根部的游离非常困难；心肌纤维坚硬、质脆，解剖时容易断离成碎块，无法沿纤维走行方向剥离。

We have battled against the odds in a province that has become increasingly violent.

我们对在一个争夺日益激烈省的可能性。