| 摘要 |
A large-capacity CDMA transmission system for communication with a mobile traveling at high speed, such as an automobile, to exchange information the quantity of which is equivalent to or more than those of conventional systems by using a frequency bandwidth equivalent to or narrower than those of conventional ones without increasing the occupied bandwidth. A code division multiple access (CDMA) transmission system in which the phase of a carrier for a predetermined period is so modulated that a predetermined value is maintained to generate a primary modulated wave, the primary modulated wave is multiplied by a spread spectrum code string, and simultaneously multiple communication is made, characterized in that a primary modulated wave is generated by differential coding phase modulation (DPSK) on the transmission side, the phase difference between the immediately previous symbol section and the current symbol section is detected by quasi-synchronous detection and differential calculation on the reception side, and the detected phase difference is used as information on the current symbol. |
