Low Frequency Ionospheric Sounding System.

摘要

The report describes a low frequency vertical pulsed sounder which makes possible soundings of the ionospheric D-region. The system employs the most recent advancements in solid state analog components and digital arrays. It features a digital intergrating scheme which is accomplished by generation of a median value of signal from 800pulses or a multiple thereof. By this means,more than 30dB in available signal to noise ratio is obtained. With selectable sample spacing as small as 1.5km,both the normal and abnormal components are separately integrated with quadrature sampling in each of 40height intervals. Other features of the phase coherent sounder include a pseudo-random phase coding for suppression of phase coherent interference and multiple hop echoes. (Author)