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Comparison of Time‐Delay Spread and Spatial Coherence for Ionospheric Propagation
Author(s) -
Felperin Karl D.
Publication year - 1966
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1002/rds196613285
Subject(s) - coherence (philosophical gambling strategy) , spatial correlation , coherence time , fading , wave propagation , delay spread , power delay profile , group delay and phase delay , physics , mutual coherence , ionosphere , mathematics , optics , computer science , telecommunications , algorithm , statistics , bandwidth (computing) , decoding methods , astronomy
This paper describes spatial selective fading (interference patterns due to modal arrival angle differences) as a homogeneous random process. It is shown that for ionospheric propagation, the power spectrum in vector wave number (wave number dispersion profile) should be of approximately the same shape as the power spectrum in time delay (time‐delay profile). On the basis of this similarity, it is suggested that the correlation between signals from spaced antennas (spatial coherence) should be inversely proportional to rms time‐delay spread. An experiment was performed on a 4100‐km path at 7 and 14 Mc/s to verify this assumption. Results are generally in agreement with theory, and discrepancies that do exist are analyzed.