If the May 2001 deadline sticks, you can expect the FCC to be liberal in granting waivers.Long live Heathkit
Readers will recall my fond recollections of Heathkit products. For those of you with similar memories, check this out.
My wife and I have a Heathkit TV kit of my dad's we are looking to sell. We tried it on eBay, but got no bids and there were no other Heathkit electronics on the site. Do you have any other recommendations? It is a Heathkit GR-2000 25" color TV with all the manuals. My father got it and only opened the boxes to take a look, then resealed them and they have sat ever since (1976?). Sadly, I have neither the time nor talent to assemble this. We'd appreciate any help you could give us. I can provide digital pictures.
Doyle R. Hill
Understanding CCIR 601 and CCIR 656
Dear Mr. Robin:
Are the horizontal and vertical sync structures of CCIR 601 and CCIR 656 similar?
Mr. Robin responds:
CCIR 601 and CCIR 656 are complementary standards. CCIR 601 deals mainly with the sampling concepts, while CCIR 656 deals mainly with the parallel and serial distribution. Both standards talk about the horizontal blanking structure. The only difference is that CCIR 656 details the EAV/SAV timing reference signal and CCIR 601 doesn't. CCIR 601 does not mention the vertical interval structure.Where's ATSC's 720 format?
I enjoyed reading your article “Getting from 4:3 to 16:9” on the Broadcast Engineering website. You did make one fairly large (to some people, anyway!) error though. There is no 720 horizontal format in Table 3 of the ATSC standard!
Mississauga, Ontario, Canada
Mr. Robin responds:
I have several comments as follows:
First, format conversions from 4/3 SDTV to 16/9 HDTV use signal sources as specified by the ITU-R BT.601 Recommendation with a 4:2:2 sampling strategy. Table 1 of the ATSC A53 lists this standard and two HDTV standards and refers to them as “Standardized Video Input Formats.”
Second, the “601” signals using the 4:2:2 sampling strategy have an active luminance sampling grid of 720 pixels by 483 lines. While the 720 sample structure is strictly adhered to, some signal sources may change the active number of lines to slightly different values. In my example I used the 720×480 source format.
Finally, the change from 720 horizontal pixels to 704 occurs in the ATSC compressor. Table 3 of the ATSC A53 lists the allowed compression formats. The ATSC document does not explain why 720 is changed to 704 in the compressor. Interestingly, the ATSC A63 version intended for countries using the 625/50 scanning format specifies 720 pixels instead of 704. So this is another ATSC item needing revision.Will the May deadline be delayed?
Dear Mr. Martin,
I read your DTV Dateline item on the Broadcast Engineering website. My company, SignaSys, is entering the DTV market by providing a low-cost DTV compliance package. I am curious what you hear about the issue of smaller commercial stations (markets 100+) that are opting to “gamble” and miss the May 2002 deadline. Some of the stations we have talked with seem to think that they will be able to argue economic hardship for a first extension, then order equipment with a long lead time in order to be able to tell the Commission that they are attempting to comply but face equipment shortages.
San Jose, CA
Mr. Martin responds:
There is a good chance the May 2002 date will be postponed, although nothing is eminent. The Commission is aware of the economic circumstances facing mid- and smaller-market TV stations (ad revenue off, network revenue off, no market for stations, bank credit tight, no market for IPOs).
If May 2002 sticks you can expect the FCC to be liberal in granting waivers. Even so, an argument of economic hardship alone probably would fall on deaf ears. Everyone can plead economic hardship to some degree (even lawyers!). Past waivers have been based on tower leasing problems, tower space shortages, tower construction delays, equipment availability and delivery problems, and zoning.