| 摘要 |
PURPOSE:To narrow a occupied frequency band width when the pulse processing FM system in the spread spectrum is employed by dividing a series of transmission information string into plural lines to apply spread spectrum modulation through the use of a multiple access technology. CONSTITUTION:A serial/parallel conversion section 5 of a transmitter 1 distributes information into 3 sets of information strings having a transmission speed of 5kbps, and spread spectrum modulation is applied in the pulse processing FM (chirp) system to obtain a spread processing gain of a 27dB by a modulation section. Since the multiple access technology is employed to superimpose the split information string onto the same frequency band in such a way, the occupied frequency band width on the transmission line is 2.5MHz, then improved. Since the multiplex by the multiple access is applied in such a way, the band narrowing processing is attained in comparison with the case of applying spread modulation to each information string as it is, and sending the result. |
