Broadcasting facilities and signal delivery
Multiplexing as a central process in ITV
The process of multiplexing is essential to digital broadcasting, as multiplexing involves merging and compressing video, audio and application data. In the DVB-T pilot project in Graz, four television channels plus additional MHP services and EPG information were broadcast in this way.
Multiplexer operation and data playout were handled centrally at ORF‘s facility in Vienna due to the need for dynamic and flexible operations. In addition to a trained professional staff, this facility also provided infrastructure for measurements and monitoring.
Signal delivery to the households
The data stream from the multiplexer output in Vienna to ORF‘s regional studio in Graz was carried by ORF‘s digital line network.
The signals were transmitted from the regional studio to Telekom Austria by way of an ATM switch in Graz, after which they were transported to the broadcast locations in Graz via Telekom Austria‘s multi-service broadband network. The Telekom Austria broadcasting facility was fed by a fiber optics-based ATM connection, while the other location was supplied by means of an SDH radio link between the facilities.
Transmission functions were monitored actively by operations personnel at Telekom Austria and ORF.
Finally, the signal for ORF 1, ORF 2 Steiermark, ATVplus and !TV4GRAZ was broadcast digitally from the two broadcasting facilities. The households which were equipped with a DVB-T and MHP-compatible set-top box were able to receive those channels along with their MHP-based additional services. The set-top box decoded the digital signal and enabled the interactive portals to be accessed individually.
