1) DVB-C
正交调制调制器
2) orthogonal design
正交
1.
In this paper, the effect of composition of transition metal oxides obtained by the orthogonal design , atmosphere and the nucleation agent on the gloss of metal glazes in ferric oxides was discussed.
采用廉价的铁系氧化物,研究了正交设计的过度金属氧化物组成、气氛、晶核剂等因素对釉面金属光泽的影响。
2.
The second and the third step reaction conditions of the synthesis of L-carvone from d-limonene were studied by the use of orthogonal design, and the whole yield of these two reactions is more than 80% by the use of new reaction conditions.
利用正交法对d - 艹宁 烯合成L -香芹酮的第二步 (脱氯化氢 )和第三步 (水解反应 )反应的工艺条件进行分析 ,得到了较为理想的工艺 ,使二、三两步反应总收率达 80 %以上。
3.
In this experiment,orthogonal design with three levels of four factors(Taq DNA polymerase, dNTPs,primer and Mg2+) was used to optimize the pepper ISSR-PCR reaction system.
本试验利用正交设计,以辣椒SS69为试材,从Taq酶、dNTPs、引物、Mg2+4因素3水平来优化辣椒ISSR-PCR反应体系。
3) Orthogonal
正交
1.
Design of Two-direction Orthogonal Partially Prestressed Concrete Beam with 32.0m × 17.0m Span;
32.0m×17.0m跨双向正交部分预应力混凝土梁的设计介绍
2.
Matri representation of the orthogonal complement in euclidan space;
欧氏空间中正交问题的矩阵描述
3.
New Definition of the Conditional Number of a Matrix──Nonorthogonal Degree;
矩阵条件数的新定义──矩阵的非正交度
4) orthogonality
正交
1.
Completeness and orthogonality of scale transformation and its proof;
尺度变换函数的完全性和正交性及其证明
2.
Regularity and orthogonality of a new family of bivariate wavelets;
一类新的二元小波的正则性及正交性
3.
Orthogonality For Defining Hermite-polynomial;
利用正交性定义Hermite多项式
5) quadrature
正交
1.
This paper analyzed the issues about the sideband and local oscillator leakage of a direct quadrature conversion transmitter, educed the quantitative relationship of the amplitude and phase imbalance in the modulation signal as well as local oscillator signal and the sideband and local oscillator leakage, and simulated it.
本文分析了直接正交上变频无线发射机中的边带和本振泄漏问题 ,导出了调制信号和本振信号的幅度和相位不平衡度与发射机的边带和本振泄漏抑制能力之间的定量关系 ,并进行了仿真。
2.
The theory of digitial calibration for the gain and phase mismatches between the in-phase and quadrature branches is discussed.
讨论了正交双通道幅相不一致的数字校正原理 ,提出了两种获得幅相误差函数的方法 ,包括最小二乘法和改进的Gram Schmidt正交化方法 。
6) orthonormal
正交
1.
Structure based on nerve net time finity orthonormal wavelet;
基于神经网络的时有限正交小波构造
2.
Characterization of Separable Bivariate Orthonormal Compactly Supported Wavelet Basis;
二元可分正交紧支集小波基的刻划
3.
The paper introduces a kind of orthonormal frequrncy division multiplexing(FDM) digital modulation technique with a good performance which can solve,in some way,the fading problem of both the channel selective one resulted from multi\|path fading and Rayleigh fading.
介绍一种可较好地解决多径衰落所引起的信道选择性衰落 ,又可克服信道的瑞利衰落、性能优良的正交频分复用数字调制技术。
参考词条
补充资料:调制器
调制器
modulator
t loozh一日-调制器(modulator)用调制信号控制载波信号三个参数(振幅、频率或相位)之一瞬时值的电子电路。被控参数为振幅时称为调幅器(a mnlitudemodulator),被控参数为频率时称为调频器(frequeneymodulator),被控参数为相位时称为调相器(phasemodulator)。调制器在通信、信号处理和自动控制系统中得到广泛应用。 调幅器实现调幅的具体电路有多种。图1(a)所示为利用一个模拟乘法器来实现的原理电路。um(t)为调制信号,u。(t)为载波信号,且峡>>aha,K为模拟乘法器的增益系数。设 u。(t)一Urneos%t,u。(t)一Uoeo。叭t,则 u‘。(t)~KUmUoeos叽teos峡t一U‘。eos田ct(1)二类。间接调频的原理是:先对调制信号进行积分,再一︵f︸日勺f,kHz┌─┬─┐│ │ │└─┴─┘冷b嘴防︺ “仁 八U‘.l.l..L产J︺。器f,k】Jz△f二7。7kljz“m(f)“。(z)┌─┐ │X │┌──┐│ ││带通││ ││ 儿││ │└──┘└─┘ _图2双边带调制的频谱 (a)调制信号u。(t)的频谱;(b)已调制信号 。飞(t)的频谱;(c)带通滤波器输出的上边带 uo(t)的频谱;(d)取用上边带信号的框图对载波信号进行调相,其输出即为已调频的信号。间接调频的优点是载波频率稳定,但频移小,电路复杂。直接调频是直接改变振荡回路的元件参数或直接控制振荡器的工作状态来实现调频的。它的优点是频移较大,线路简单,但载波频率稳定性较差。图3是利用变容二极管的直接调频电路。图中:v七Ll、cl、凡、RZ、c:构成正弦波振荡电路;vZ、LZ和电源U组成变容二极管偏置电路;。。(t)为调制信号;u。(t)为已调频信号;瓜是高频扼流圈,它阻止高频输出电压u。(t)通过,以免影响调制电压um(t),而允许低频的调制电压um(,)通过去改变变容二极管vZ的两端电压,从而改变v琴的电容,达到改变正弦振荡器输出频率的目的。- 图3用变容二极管的调频电路 调相器调相器的电路也可分为直接调相和间接调相二类,图4为利用移相网络来直接调相的原理电路、图中yl组成倒相电路,。。(t)为载波电压,集电式(l)中,乘法器的输出电压振幅酬。一K队Umcos叽t受调制信号蝙(t)控制,故称振幅调制器,简称调幅器。式(1)又可化为U,。(右)一音K-U·U。「。
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