Accession Number : AD0675429

Title :   MULTICHANNEL SHORT WAVE TELEGRAPH COMMUNICATION AND AUTOMATIC ERROR CORRECTION,

Corporate Author : FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Wang Ch'i,

Report Date : 05 JAN 1967

Pagination or Media Count : 15

Abstract : The author discusses some aspects related to short-wave multi-channel telegraph communication and automatic error-correcting techniques. The frequency- and time-division multiplex were analyzed to study frequency distribution at various keying speeds. The expressions for statistical probability of envelope power and for power distribution in a facsimile system were extended, taking into account Rayleigh distribution of probability density and peak envelope power of the facsimile channel. Reduction of frequency band and elimination of station interferences were effected by adopting the sine-wave keying method at the sending end. A keying speed of 96 bands was reached by adding an automatic correcting device. A 'ganged tuning' type filter was introduced to reduce the transmission distortion resulting from fading effects at the receiving end. Comparison of diversity gain was made between frequency and space diversities to study elimination of fading effects. System stability was analyzed with respect to error-detecting and correcting codes. (Author)

Descriptors :   (*COMMUNICATION AND RADIO SYSTEMS, TELEGRAPH SYSTEMS), SINGLE SIDEBAND COMMUNICATIONS, MULTIPLEXING, FREQUENCY, STATISTICAL DISTRIBUTIONS, PROBABILITY DENSITY FUNCTIONS, ERRORS, CORRECTIONS, AUTOMATIC, GAIN, FREQUENCY SHIFT, STABILITY, POWER, RADIO INTERFERENCE, MATHEMATICAL ANALYSIS, CHINA

Subject Categories : Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE