| 摘要 |
PURPOSE:To provide the spread spectrum communication system provided with amplitude information similar to that of the QAM modulation system through it is a modulation system keeling a fixed amplitude. CONSTITUTION:A QAM coding section 12 maps input data onto I, Q phase planes and changes each phase and each amplitude. Spread sections 15, 16 apply spread spectrum processing to the I, Q by the same spread code. Multipliers 18, 19 multiply a sin component and a cos component of a local signal 17 and a synthesizer 20 synthesizes the products. A 1/2 distributer 22 distributes the synthesized product into I and Q components and multipliers 23, 24 multiply a local signal with the I and Q components and the product is digitized and given to correlation devices 30, 31, in which the amplitude component is discriminated and its correlation output is demodulated by a QAM demodulation section 35. |
