The BBC has conducted experiments with signals for satellite broadcasting to demonstrate the possibilities of enhancement to both vision and sound. The resultant signal has a different spectrum from that of a conventionally coded signal. Thus it is necessary to examine interference protection ratios for the enhanced signal and determine any differences from those assumed in the WARC satellite broadcast plan.

This report considers the interference effects of, and the protection ratios required by, an enhanced signal comprising an Extended PAL video signal and a digitally-modulated sound sub-carrier. It is shown that the protection ratios assumed in the WARC plan are not infringed.

At the time of the final preparation of this report Extended PAL was no longer being proposed as a UK DBS transmission standard. The report is, however, being issued as a complete record of the work.