ISIS-1 Topside Sounder Average Ionogram over Kerguelen Island, France: KER, Latitude -49, Longitude 70

This Ionogram was digitized from the original ISIS 1 Analog Telemetry Data on 7-Track Tape using the Facilities of the Data Evaluation Laboratory at NASA GSFC, Code 500. This Data Restoration Project is headed by Dr. R.F. Benson, NASA GSFC, Code 692. Ionograms were digitized at the Rate of 40,000 16-bit samples/s. This Sample Rate is higher than the Nyquist Frequency of 30 kHz. The Sample Frequency of 40 kHz provides a Measurement every 25 ms corresponding to an Apparent Range Interval of c*t/2, where c is the Speed of Light, or 3.747 km. Each Ionogram consists of a Fixed Frequency Portion and a Swept Frequency Portion. The Time Resolution is typically 29 s.

本电离层图系由原ISIS 1模拟遥测数据经数字化处理所得，数据源于NASA戈达德太空飞行中心数据评估实验室的7轨磁带设施，代码编号为500。此项数据恢复项目由NASA戈达德太空飞行中心R.F. Benson博士领衔，代码编号为692。电离层图以每秒40,000个16位样本的速率进行数字化处理。该采样率高于30 kHz的奈奎斯特频率。40 kHz的采样频率保证了每25毫秒进行一次测量，对应于光速c乘以t/2的视距间隔，其中c代表光速，约为3.747公里。每张电离层图由固定频率部分和扫描频率部分组成，时间分辨率通常为29秒。