Charles W. Rhodes
By the time you read this, the FCC is expected to propose a set of rules by which unlicensed devices will be allowed to share TV Channels 2–51.
Two more reports of laboratory testing of DTV receivers have recently been made public and the news does not portend well.
The FCC Laboratory report on the interference rejection capabilities of modern DTV receivers dated March 31, brought to my attention the fact that many viewers live in relatively weak signal areas.
This column has been dealing with DTV-DTV interference and has almost completed this discussion.
I replaced my 27-inch CRT receiver with a 42-inch plasma panel HDTV display more than a year ago, and I've never regretted doing so.
While many broadcasters may wish that DTV was not about to replace analog terrestrial broadcasting, that is unrealistic. Broadcast spectrum is going to be reduced dramatically and soon.
My concern is the interference such signals may cause to reception near the secondary transmitters
Any active device, amplifier or mixer will generate second order distortion products given that the input signal voltage overloads the active device.
The FCC has defined how close to, but outside of the predicted noise-limited perimeter of a station, a DTVB can be operated on the same channel as a DTV station in that community.
This is the first allotment table having no analog TV channel allotments; it is our future broadcasting universe.
In this market, all vacant channels in the high VHF and UHF bands are also adjacent channels to one or two broadcast channels. So are adjacent channels really suitable for sharing?
Had the FCC been able to anticipate this problem of receiver-generated IM3 (noise) in ���vacant channels,” perhaps it could have established minimum performance standards for consumer DTV receivers.
Last month, this column covered DTV-DTV interference from one and two undesired signals. In this issue, we will address the matter of triplets of undesired DTV signals.
They found that signals of this form produce what amounts to co-channel interference into channel N. Take my word for it, they would also have found the same in channel N+3K.