Brad Fortner of the Rogers Communications Centre at Toronto’s Ryerson Polytechnic University is promotions advisor for the Toronto Section of smpte.

Discussion at the January meeting of the Toronto Section of the Society of Motion Picture and Television Engineers challenged the thesis that terrestrial digital transmitters are required to deliver hdtv in Canada.

The meeting, broadcast to a North American audience via satellite, was set up by the Montreal, Ottawa and Toronto smpte sections to help define a Canadian perspective on the path to digital transmission and high definition.

It brought together some of Canada’s leading television engineers from all areas of the broadcast industry to review the current status and share ideas.

David George, immediate past president of smpte, hosted the broadcast. ‘Unlike the United States, the conversion to digital television in Canada is not mandated by law,’ he noted.

He also noted that cable tv is central to the system of distributing television in Canada and is one of the key factors that makes the Canadian transition different to what is occurring south of border.

The American experience

Stephen Pumple of immad – ecvs opened the evening by reviewing the American dtv experience to date. Pumple has had direct experience with dtv through his company’s efforts in converting several u.s. broadcasters to dtv.

He reminded the audience that dtv is a digital transmission standard that was constructed for use by over-the-air broadcasters. Known as the atsc standard, it differs from our current ntsc transmission system in that it transmits signals digitally. atsc transmits at least 18 different image types. They range from the resolution of our current television system, through to high-definition television images. Should a broadcaster choose to transmit lower resolutions, then it is possible for that broadcaster to transmit several stations in the allotted transmission spectrum.

‘Confusion around formats is the key problem that we’ve run into,’ Pumple commented. ‘It gets even more confusing because broadcasters can switch formats during the day.’

Another new feature of 19.39 Mbits/sec atsc signal is its ability to transmit data streams directly to the home. ‘I have no doubt that marketing people will find a way to take advantage of these data streams in short order,’ Pumple noted.

Pumple also covered the aggressive American schedule that includes a seven-year simulcast period where current ntsc transmission will continue and the new atsc signals will be phased in.

‘By 2004, 70% of the material transmitted on the ntsc channel must be simulcast on the atsc channel,’ he said. ‘By Dec. 31, 2006, it must have reached 100%, and it’s at this point when the fcc plans to stop ntsc broadcasting in the United States.

One apparent flaw in the atsc standard is that it was designed specifically for over-the-air broadcasters. Its design did not take into consideration how direct-to-home satellite or cable would distribute the signal in the digital domain.

The engineering challenge centers on differences in the way the signals are modulated. The atsc standard uses 8VSB modulation, while cable uses quam and dth uses qpsk. Who and how these signals are to be converted for distribution has the potential to create problems, especially in Canada.

Canada’s DTV position

‘Small market, big country. This is the reason that Canada has to concern itself with the implementation of dtv,’ opened Carol Darling’s presentation on the Canadian implementation of dtv. Darling feels that if Canada does not act, Canadian consumers will start disconnecting.

‘They proved it first with color television and more recently with direct-to-home television,’ said Darling, vp, engineering, operations and affiliate relations at wtn, who’s currently serving on the technical committee of cdtv (Canadian Digital Television Inc.).

Darling reported on the progress made as a result of the report on Canadian Television in the Digital Era put together by the task force on the implementation of digital television.

‘The government has accepted our recommendation that dtv must be clearly superior [in quality] and has accepted the position that it must be a 16:9 aspect ratio. It has gazetted coverage areas for current broadcasters, agreeing that competing broadcasters will be able to share digital transmitters and transmission facilities. It has also created Canadian Digital Television Inc. to help guide the Canadian broadcast industry through an orderly transition into digital transmission,’ she reported.

Darling then spoke of the work being considered by the technical committee, of which she is a member. The work potentially includes a test dtv transmitter, format and bitrate tests and a joint master control and transmitter project that would test end-to-end transmission issues.

Darling concluded her presentation by encouraging support for cdtv through membership or the loan of equipment that would assist with testing.

I want my DTV

Lou Montana of Montana Engineering was next to the podium to talk about the technical issues involved in setting up a dtv plant.

Montana has had extensive experience in this area. He engineered Canada’s first hdtv mobile and later went on to manage the technical side of two digital component broadcast plants for Netstar.

‘dtv is a complicated process and Canada risks being bogged down and falling behind the u.s.,’ he said. ‘Although Canada is not mandated to convert to dtv, many of our broadcasters have taken the first step by building their plants to be 601 digital. Ninety percent of American broadcasters are analog ntsc and have not even taken the first step.’

To assist broadcasters with dtv conversion, Montana then covered areas that broadcasters need to concern themselves with. Among the issues he discussed were issues relating to origination in the broadcast plant and issues dealing with e-mission.

‘dtv requires many more control parameters over analog,’ he explained. ‘atsc was designed as a direct-to-home transmission standard for over-the-air broadcasters. It includes a layer for conditional access, allowing for subscription to additional services.

‘atsc, however, did not take into account cable or dth satellite distribution, which accounts for 85% of the delivery to Canadian homes. How conditional access signals and ancillary data pass through the systems and who controls them in the delivery chain will be an issue,’ he speculated.

‘Broadcast coverage areas in Canada have been based on the assumption that the home antenna is placed on a nine-meter tower and the consumer has purchased a line amplifier,’ Montana noted.

Montana closed his presentation by urging cooperation among broadcasters during the conversion process. Montana feels that if Canadian broadcasters would agree on a single e-mission format it would simplify matters for Canadians.

DTV to the home

already in place

‘It is arguably true that we currently have digital in place in Canada for standard definition television,’ said Roger Keay, vp, technology and strategic planning for Rogers Communications. Keay was referring to the fact that both digital cable and dth satellite currently deliver digital television from their respective plants directly to a set-top box.

‘Like over-the-air spectrum, cable has bandwidth limitations too,’ said Keay. ‘Cable must continue to provide analog television for some time to come along with delivering these newer digital services.’

He explained that the 8VSB modulation employed in atsc uses greater bandwidth than quam modulation employed in cable. ‘This is because cable is a low-noise environment when compared to over-the-air transmission,’ he said. ‘However any hurdles in this area have been overcome with the availability of vsb to quam converters.’

Keay also addressed the intellectual property issue. The issue arose when the IEEE-1394 digital interface was chosen. Hollywood producers are concerned that once a signal is decoded by a set-top box it will be able to be recorded digitally at the same quality as the master tape. Keay is confident that newly developed point of distribution modules for IEEE-1394, will result in an acceptable solution.

In closing his presentation, Keay seemed confident that between the modulation converters and the pod modules any issues around cable handling atsc signals have been resolved.

Broadcasters’ view

The meeting concluded with a panel discussion about dtv that included broadcasters from every Canadian sector. Terry Snazel from ExpressVu, Bruce Cowan from Citytv, Harvey Rogers from History/Showcase and Rudi Linghor of the cbc all took the hot seat to best represent a constituency of Canadian broadcasting.

Representing dth broadcasters, Snazel opened by focusing on the common technological denominator. He reminded the audience that despite the various digital delivery methods, terrestrial broadcasters, dth providers and cable are all delivering MPEG 2 television. He feels that this concept should be kept in mind as Canada develops its dtv policy.

‘dth satellite is the most cost effective method for delivering MPEG 2, thus high-definition television in Canada.’ he said.

Snazel talked about ExpressVu’s ‘Super Definition.’ By increasing the digital bandwidth, ExpressVu is able to transmit images that are comparable to dvd. Snazel expects to have the Super Definition service in place by summer and full hdtv by the end of next year.

Bruce Cowan of City, representing terrestrial broadcasters, has trouble believing that people will put up antenna masts to view hdtv.

‘In the ideal world a new digital transmission system would have allowed for a more mobile form of tv.’ he said.

Cowan sees all sorts of practical problems associated with atsc.

‘Since there is no space left at the CN Tower transmission site, Citytv would have to remove its backup transmitter to accommodate the dtv transmitter. This would leave us without a backup for our ntsc service and it raises the question of a backup transmitter for the digital service. For an organization like chum, the cost of new transmitters for its television operations would be in the area of $20 million to $30 million,’ he said.

Rogers of Showcase/History wondered where the money was to come from for this conversion.

Representing specialty channel operators he noted that the audiences of specialty channels are often limited to a particular area of interest. Rogers is concerned that in going digital, the technology of new sets and set-top boxes will further restrict the audience and erode the subscription base.

‘Satellite congestion for distribution of our services is our main problem,’ Rogers noted. ‘Currently many specialty services are compressing their signals to share limited transponder space. This means the quality at which we can deliver our signals to our suppliers across Canada [cable and dth] is limited.’

Rogers concluded his discussion by suggesting that Canadian broadcasters get together and start a ‘sampler channel.’ The channel would feature a sampling of each member’s programming on a rotating basis for a couple of hours each day and serve to whet Canadians’ appetite for digital services and hdtv.

Rudi Linghor of the cbc spoke on how his organization is interested in getting digital-quality video to the home. However, like all terrestrial broadcasters, he wonders where the money is going to come from to replace the 600 ntsc transmitters that the cbc operates across the country.

Currently, to get around transmitter limitations, cbc’s Broadcast Centre in Toronto delivers its digital output directly to Rogers Cable for distribution, as does tsn and the Shopping Channel.

With almost 100% of the country covered by cable and/or dth many in the audience wondered if this was not the route Canada should go in delivering digital and high-definition services.

Perhaps Bruce Cowan of City summed it up best. ‘I’ve often thought that since the Canadian government does not plan to auction ntsc spectrum space, Canadians have a different path. Perhaps Canada could retain ntsc for the distribution of free tv for some time to come.

‘Canada can wait until it’s both financially and technically feasible for the terrestrial broadcaster and consumer to complete the conversion. And, in the meantime, the cable and dth providers that currently provide service to 85% of Canadians can receive the digital content directly from the various broadcasting organizations and provide the wide-screen, high-definition content to the consumers who want it.’