We asked Bruce Jacobs of PBS:
In your view does all of this activity now point to the inevitable labor of "changing" the standard--an FCC process of some kind--or is it more a kick in the seat of the pants to the 8-VSB reeiver makers warning them to get the job, done or else?
Bruce responds:
I think it is a call for ANY 8VSB proponent to demonstrate within the next three months the ability of 8VSB to be sufficiently improved.. If such improvements can be demonstrated and we can be confident that they soon will- wonderful. We will move forward with greater speed and confidence.
If such improvements cannot be demonstrated, it would be in the public interest to change the standard <even if> such improvements are possible, The greater confidence in the resulting standard would boost consumer confidence and speed the roll-out over continuing with 8VSB.
My recommendation is that broadcasters accept whatever real loss, if any, in distant reception results from transmitting COFDM at the same average power level, and accept the table as it exists for use with COFDM. Every broadcaster I know, even rural broadcasters, seem willing to accept a minor loss in distant reception if what they gain is a big improvement in urban receivability. They feel that rural viewers often have good antenna systems, and urban viewers cannot be forced to install such and in many cases cannot if they try.
Suffice it to say, as much as I believe in lab testing, field tests demonstrating 8VSB's "further reach" are now necessary to counter the field test I know of, that shows that it is not. The field is not neat or easily quantified, but people do not live in laboratories!
There will be cases where the allocations would ideally be changed (single frequency approaches) because of the characteristics of COFDM. This can be done on a case-by-case basis, and if anything should result in tighter packing. But if we stick with the same average power levels, there should be no change in the interference into NTSC. Pending evidence to the contrary, I for one would be willing to accept the risk of worse DTV into DTV and NTSC into DTV interference, given the apparent advantages. So, my trial balloon is this:
- Petition the FCC to add COFDM as a modulation option, at the same power level, at broadcaster's discretion.
- Require dual-mode receivers, either as an FCC rulemaking, or as a
defacto industry agreement.
- Present this to the public as it is- a minor change to the standard- like an upgrade to the modem on their computer.
Regards,
Bruce Jacobs
