著者

井出 正 佐野 実 新井 重男

出版者

The Iron and Steel Institute of Japan

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.72, no.11, pp.1674-1680, 1986-09-01 (Released:2010-02-15)

参考文献数

16

著者

望月 寛 浅野 晃 佐野 実 高橋 聖 中村 英夫

出版者

The Institute of Electrical Engineers of Japan

雑誌

電気学会論文誌. D, 産業応用部門誌 = The transactions of the Institute of Electrical Engineers of Japan. D, A publication of Industry Applications Society (ISSN:09136339)

巻号頁・発行日

vol.126, no.3, pp.337-344, 2006-03-01

被引用文献数

8 1

---

Recently, QAM (Quadrature Amplitude Modulation) transmission is paid to attention in digital modulation method, and it has been used for wireless LAN and digital broadcasting. QAM is a modulation method that puts information on carrier amplitude and phase. So QAM can achieve high-capacity data transmission that the use efficiency of frequency band is good. But QAM has a bad characteristic that is weak to the noise and the interference because distance between each symbol is short. Then we propose the method that not transmission data but CDMA signal, obtained after transmission data is modulated by spread code and multiplexed, is given to each symbol of QAM. And we studied about railway signal system on track circuit as a sample to apply this method. As result of computer simulations, we verified to be able to achieve the improvement of signal to noise ratio by optimizing the constellation map of QAM. We report with the method of a synchronous acquisition.