@article{oai:uec.repo.nii.ac.jp:00006813,
 author = {冨澤, 一郎 and Tomizawa, Ichiro and 柴田, 喬 and Shibata, Takashi and 奥澤, 隆志 and Okuzawa, Takashi and 有澤, 豊志 and Arisawa, Toyoshi and 瀬尾, 洋一 and Seo, Yoichi and 足立, 登 and Adachi, Noboru},
 issue = {1},
 journal = {電気通信大学紀要},
 month = {Jul},
 note = {Radio sounding techniques have commonly been used for observation of ionospheric disturbances because of their high sensitivities in detecting signals reflected or scattered by electrons or ions in disturbed regions. High-Frequency-band Doppler(HFD) observation technique is the most sensitive one for detecting movement of the disturbed regions since it can be applied for the spectral analyzing technique. It is therefore popular that the HFD technique has long been used for this purpose. However, we had to give up the HFD observation since the reference signal transmitted as the HF-band standard signal station JJY were reported in termination at the end of March in 2001.<P> Then, we started the project in 2000 for constructing a new reference transmitting station to continue the HFD observation. We had been developing an HF transmitting station specialized for the HFD observations. The new HF transmitting station with 200 W has the sufficient stability to detect as small deviation as 10-8 within the 1,000 km range from the UEC Chofu-campus in Tokyo.<P>The transmission frequencies, 5.006 and 8.006 MHz, are allocated based on the research of minimum interfering frequencies close to the old-JJY transmission frequencies, 5 and 8 MHz. To minimize spurious caused by inter modulation distortion both in transmitter and in receiver, the amplitude modulation of the station ID is set in single sideband with low modulation index. The HFD station, JG2XA, started transmission on July 3, 2001, and it continues transmission for HFD observations since then.},
 pages = {83--93},
 title = {電離層擾乱観測用短波送信システムの開発},
 volume = {16},
 year = {2003},
 yomi = {トミザワ, イチロウ and シバタ, タカシ and オクザワ, タカシ and アリサワ, トヨシ and セオ, ヨウイチ and アダチ, ノボル}
}