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2. 发明授权

US5546428A Differentially encoding quadrature phase shift keying modulation method and apparatus thereof 失效
标题翻译：差分编码正交相移键控调制方法及其装置
公开(公告)号：US5546428A
公开(公告)日：1996-08-13
申请号：US132262
申请日：1993-10-06
申请人： Il-hyun Nam , Kwan-seong Kim
发明人： Il-hyun Nam , Kwan-seong Kim
IPC分类号： H04N19/50 , H04L25/49 , H04L27/20 , H04L27/34 , H04N9/65 , H04N19/42 , H04N19/423 , H04N19/80 , H04N19/85 , H03C3/00 , H03K7/06 , H04L27/10
CPC分类号： H04L25/49 , H04L27/2071
摘要： A differentially encoded quadrature modulation method comprises the steps of setting an index corresponding to a phase variation value constituted of input data, forming a phase value to obtain a phase-modulated output phase value from a given table and forming a channel signal to obtain in-phase (I) and quadrature (Q) channel signals from a given table using the phase value. The apparatus for performing the above comprises a signal converter for converting serially input data into two binary signal trains, a signal forming portion for obtaining channel signals, a digital-to-analog converter for converting the respective signals into two analog signals, a baseband filter for baseband-pass-filtering the signals, a phase shifter for shifting a carrier by 90.degree., first and second multipliers for multiplying the filtered signals with the carrier and phase-shifted carrier, respectively, and a mixer for mixing the respectively obtained signals and outputting a combined signal. Accordingly, the phase difference according to symbol is implemented alter being assigned to the corresponding index value stored in a look-up table. The final modulation output phase together with the previous phase value is directly obtained by using the look-up table. Accordingly, the construction of the circuit is simplified and the size of the chip is reduced for lower power consumption. Also, modulation speed is improved and a reliable modulation signal can be formed.
摘要翻译：差分编码的正交调制方法包括以下步骤：设置与由输入数据组成的相位变化值相对应的索引，形成相位值以从给定表获得相位调制输出相位值，并形成通道信号，相位（I）和正交（Q）通道信号。用于执行上述的装置包括用于将串行输入数据转换成两个二进制信号串的信号转换器，用于获得信道信号的信号形成部分，用于将各个信号转换成两个模拟信号的数模转换器，基带滤波器用于对信号进行基带通滤波，用于将载波移位90°的移相器，用于将滤波后的信号与载波和相移载波相乘的第一和第二乘法器，以及用于混合分别获得的信号和输出组合信号。因此，根据符号的相位差被改变分配给存储在查找表中的对应的索引值。通过使用查找表直接获得最终调制输出相位与前一相位值的相位。因此，简化了电路的结构，并且为了降低功耗而降低了芯片的尺寸。此外，调制速度提高，可以形成可靠的调制信号。

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