| 摘要 |
<P>PROBLEM TO BE SOLVED: To increase a transmission speed while preventing transmission quality from deteriorating. <P>SOLUTION: At a serial/parallel converter 10, information to be transmitted is inputted in bit units for outputting as X, Y, and Z. At a differential coder 12, X and Y are differentially coded, and π/4 shift QPSK-modulated for outputting I and Q. At an orthogonal modulator 18, I and Q are orthogonally modulated. At an adder 28, a signal outputted from the orthogonal modulator 18 is added. An oscillator 20 and a second switch 34 are operated by switches operated in a pair so that an attenuator 32 is not passed when Z is set to "1". When the Z is "0", the oscillator 20 and the second switch 34 are operated so that the attenuator 32 is passed. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
