Alouette-2 Topside Sounder Average Ionogram over Winkfield, United Kingdom: WNK, Latitude 51, Longitude 359

This Ionogram was digitized from the original Alouette 2 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 31 s.

本电离图（Ionogram）源自7轨磁带上的原始阿洛埃特2号（Alouette 2）模拟遥测数据，由美国国家航空航天局戈达德航天飞行中心（NASA GSFC）代码500部门的数据评估实验室完成数字化。本次数据修复项目由NASA GSFC代码692部门的R.F.本森博士牵头负责。所有电离图均以每秒40000个16位采样的速率完成数字化，该采样率高于30千赫兹的奈奎斯特频率（Nyquist Frequency）。40千赫兹的采样频率每25毫秒完成一次测量，对应表观距离间隔为c·t/2（其中c为光速，该间隔数值约为3.747千米）。每张电离图均包含固定频率段与扫频频段两部分，其时间分辨率通常为31秒。