Accession Number : AD0286277

Title :   LUNAR REFLECTION STUDY

Corporate Author : AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS

Personal Author(s) : CLAXTON,BRIAN H. ; ANDERSON,ROY E.

Report Date : 31 AUG 1962

Pagination or Media Count : 1

Abstract : The effective bandwidth of the lunar reflection path was determined. Doppler shift, signal strength, and amplitude fading of CW signals were measured, and the results analyzed and compared to theoretical predictions. Double sideband suppressed carrier transmissions centered at 915 Mc, with audio frequency modulation to produce two signals separated in frequency by a small amount, were re lected from the moon and received. The amplitudes of the two sidebands were separately recorded, and their correlation coefficient computed to give a measure of the quality of the circuit. Forty-five determinations of the correlation coefficient for 500 cps sideband separation gave a value of .26 ! .07, showing that the coherent bandwidth of the moon reflection path is extremely narrow. A standard word list was transmitted as a test on the actual quality to be expected of a voice circuit using relatively unsophisticated terminal equipment. A panel of listeners correctly ascertained 74% of the moonreflected words, whereas 95% o the words on a similar list presented without distortion but in the same signal/white noise environment, were correctly judged. The difference is attributed to fading more than to distortion of the moonreflected words. (Author)

Descriptors :   *ELECTROMAGNETIC WAVE REFLECTIONS, *MICROWAVE NETWORKS, *MOON, *COMMUNICATION AND RADIO SYSTEMS, *RADIO RECEIVERS, *RADIO TRANSMITTERS, DOPPLER SYSTEMS, FREQUENCY MODULATION, MODULATION, SIDEBANDS

Distribution Statement : APPROVED FOR PUBLIC RELEASE