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    • 4. 发明授权
    • Group modulator
    • 群调制器
    • US5430711A
    • 1995-07-04
    • US201989
    • 1994-02-25
    • Yoshifumi YamadaTadashi Shibato
    • Yoshifumi YamadaTadashi Shibato
    • H04J1/06H04J4/00H04J11/00
    • H04J1/06H04J4/005
    • A group modulator provided a plurality of digitally modulated signals with frequency division multiplex, having a time division multiplexer (11) for multiplexing a plurality of input data (#l through #n). A mapping circuit (12) provides an I-channel signal and a Q-channel signal according to a pattern of the multiplexed signal and the modulation system. A pulse shaping circuit (13) restricts bandwidth of the I-channel signal and the Q-channel signal. A frequency shift circuit (14) shifts frequency of the I-channel signal and the Q-channel signal by the frequency defined by the carrier control signal (i) for each input data. An accumulator (21,22) accumulates each of the I-channel signal and the Q-channel signal of the output of the frequency shift circuit (14) during a predetermined period (T). A D/A converter (31, 32) converts the output of the accumulator from digital form to analog form. A low pass filter (41, 42) is provided at the output of the D/A converter. A quadrature modulator (5) modulates carrier frequency (f.sub.c) with quadrature modulation according to the I-channel signal and the Q-channel signal at the output of the low pass filter. A multiplicity control (6) controls multiplicity in the time division multiplexer (11) according to an external multiplicity signal.
    • 组调制器提供具有频分复用的多个数字调制信号,具有用于复用多个输入数据(#1至#n)的时分多路复用器(11)。 映射电路(12)根据复用信号和调制系统的模式提供I信道信号和Q信道信号。 脉冲整形电路(13)限制I信道信号和Q信道信号的带宽。 频移电路(14)通过对于每个输入数据由载波控制信号(i)定义的频率移位I信道信号和Q信道信号的频率。 累加器(21,22)在预定时段(T)期间累积频移电路(14)的输出的I信道信号和Q信道信号中的每一个。 D / A转换器(31,32)将累加器的输出从数字形式转换成模拟形式。 在D / A转换器的输出处提供低通滤波器(41,42)。 正交调制器(5)根据I通道信号和低通滤波器输出端的Q信道信号,调制载波频率(fc)。 多重控制(6)根据外部多重信号控制时分复用器(11)中的多重性。