| 摘要 |
PURPOSE:To perform the data communication for data transmission between plural mobile stations and a base station, by receiving a radio wave at the base station from the mobile station, and demodulating the information at the base station in correlating with a pseudo noise code which is equal to that of the mobile station. CONSTITUTION:A radio wave (frequency fi) is received at an antenna 4 from a mobile station. This received radio wave is supplied to a frequency converter 7 through a circulator 17, a BPF5 and an amplifier 6 to receive a conversion of frequency with the signal of a local oscillator 8 (frequency f1). A demodulator 3 demodulates the information sent from a mobile station. The output of the oscillator 8 is also supplied to another frequency converter 14 to receive a conversion of frequency with the signal of an oscillator 15 (frequency f1-fi+ mfc1 or f1-fi-mfc1) and changed into a signal having a frequency component of fi-mfc1 or fi+mfc1. This signal is transmitted via a BPF16 which transmits a signal having a frequency component of fi-mfc1 or fi+mfc1 and a circulator 17 and through the antenna 4. |
