TRANSMISSION QUALITY OF GROUP-III FACSIMILE ON IDR SATELLITE LINKS WITH CIRCUIT MULTIPLICATION EQUIPMENT

The focus of this paper is on ways to improve the quality of Group III facsimile on intermediate data rate (IDR) satellite links. First, we present the results of an evaluation of the quality of Group III (G3) facsimile images transmitted on satellite links through circuit multip lication equipment (CME). Based on the results of this study, we propo se a model to relate the facsimile image quality requirements to the b it error ratio (BER) on the link. A procedure is introduced to associa te the long-term percentage of error-free pages in G3 facsimile transm ission with various bit error probability (BEP) masks used for satelli te link design. The intent of this procedure is to provide comparable end-to-end transmission quality for international telephone circuits, irrespective of whether the transmission medium is a satellite link or a fibre-optic cable. It is concluded that, unless the performance obj ectives of satellite systems significantly exceed those derived from C CITT/ITU-T Recommendation G.826, fibre-optic cables will become the pr eferred choice for international transmission.