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Accession Number:
AD0837412
Title:
COMPUTER SIMULATION OF FREQUENCY-SELECTIVE FADING OF HF RADIO SIGNALS AND OF THE IMPROVEMENT AFFORDED BY MODE-AVERAGING RECEIVING TECHNIQUES.
Corporate Author:
STANFORD UNIV CA STANFORD ELECTRONICS LABS
Report Date:
1968-06-01
Abstract:
The amplitude of a single-frequency, ionospherically-propagated HF radio signal fluctuates, or fades, with time. This fading is caused by the interference between waves traveling along different paths between transmitter and receiver and by the changing nature of the ionospheric layers. When a number of single-frequency CW signals within some transmission passband are transmitted, it is found that the amplitudes of the various received components are not equal. This is called frequency-selective fading. Three versions of a diversity-combining principle, called mode-averaging, were studied to determine the degree of reduction of frequency-selective fading afforded by the use of this principle. First, a computer simulation of frequency-selective fading which occurs in a single non-diversity receiver was devised. The actions of the three-mode-averaging schemes were then simulated and the improvement in frequency response afforded by each scheme as compared with the single receiver was evaluated. The influence of antenna array spacing for one of the mode-averaging schemes was also studied with the aid of a computer, and the most desirable spacing determined. Author
Descriptive Note:
Technical rept.,
Pages:
0070
Contract Number:
Nonr-225(83)
File Size:
0.00MB
