Adjacent Channel DVB-H Interference into Analogue PAL Television

No part of this document may be copied or otherwise reproduced without the prior written permission of ERA Technology Limited. If received electronically, recipient is permitted to make such copies as are necessary to: view the document on a computer system; comply with a reasonable corporate computer data protection and backup policy and produce one paper copy for personal use. If no restrictive markings are shown, the document may be distributed freely in whole, without alteration, subject to Copyright. 3 Summary As part of the Digital Dividend Review (DDR), ERA was asked by Ofcom to investigate the potential interference of services using digital video broadcast-handheld (DVB-H) into analogue PAL television receivers. Three different types of analogue television were tested: 1. LCD with analogue RF (Receiver 1) 2. Portable television (Receiver 2) 3. Typical home television using a cathode ray tube (CRT) (Receiver 3) Five different interference cases were investigated based on three different DVB-H bandwidths of 6, 7 and 8 MHz. For three of the cases the DVB-H bandwidths (of 6, 7 and 8 MHz) were centred in a transmission filter of nominally 8 MHz. This was to determine whether DVB-H could minimise interference into PAL by commencing transmissions at a narrower bandwidth, but transition to an 8 MHz bandwidth post digital switch-over without having to change the transmit filters. The remaining two cases investigated assumed that suitable 6 or 7 MHz transmitter filtering was available and that a guard band (of 1 or 0.5 MHz respectively) was therefore created. These DVB-H signals were used to measure N-1 (channel 37) and N+1 (channel 35) adjacent channel interference into analogue PAL television, using both a non-critical and critical DVB-H transmit filter. The carrier-to-interference (C/I) ratio was measured using a five-point scale based on Recommendation ITU–R BT.500 [6] to subjectively assess the picture quality of the analogue reception. From the results shown in Appendix A, it can be concluded that the C/I protection ratios using 6 or 7 MHz transmissions with guard bands created by filtering are similar to those of the DVB-H signal centred in the channel, but using an 8 MHz filter, for both 6 and 7 MHz bandwidths respectively. When testing for N-1 DVB-H interference, the critical filter was found to improve the initial signal quality for the majority of situations tested compared with the non-critical filter. Also, from the measurement results, the C/I protection ratio improves with respect …