Digital TV: Charles W. Rhodes

Charlie Rhodes is a consultant in the field of television broadcast technologies and planning. He can be reached via e-mail at charleswrhodes@worldnet.att.net

NTIA Proposes Minimum Performance Standards
The ATSC document A/74: ATSC Recommended Practice: Receiver Performance Guidelines could be the basis for National Telecommunications and Information Administration performance standards for the 10 million federally subsidized digital-to-analog converters.

White Spaces Are There For a Reason
I have recently written about the hot topic of sharing broadcast spectrum with unlicensed devices.

Television Reception History Repeats Itself
The January 1954 issue of "Proceedings of the Institute of Electrical and Electronic Engineers" was a special issue devoted entirely to the NTSC compatible color television system adopted by the FCC.

What Is That Noise in the White Channel?
The FCC proposes for unlicensed transmitters operating in the TV bands (Channels 4-51), a transmitter power output limit of 1 watt in the white channel for fixed facilities and 100 mW for portable facilities.

Unlicensed Devices Could Compromise EAS
Since my article in the Oct. 19, 2005 issue of TV Technology, ("Developing a 24/7 Digital EAS System"), some real progress has been made by the FCC in the matter of the Emergency Alert System.

More RF Power To the People
In August, this column took up some aspects of the measurement of DTV transmitter power output. You might wonder why I used the phrase "DTV transmitter power output" instead of "effective radiated power," since ERP appears on your license and that's what the FCC regulates.

Developing a 24/7 Digital EAS System
On Aug. 12, I sent my column for the September issue to my editor. Little did I know how soon the Emergency Alert System would come into play, nor the terrible destruction the homeland would soon suffer. After discussions with broadcasters and before Katrina, I started to study the EAS.

Poised at the Great Analog/DTV Divide
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.

RF Power to the People: Measuring DTV Signals
Recently, a reader wrote to me seeking a copy of a paper on measuring the transient peak-to-average power ratio of DTV signals. So perhaps the topic of DTV signal power, which is so different from analog TV signal power, is of interest to many readers.

The Superheterodyne Concept and Reception
Today we don't use vacuum tubes in receivers, but all radio and TV receivers use Armstrong's superheterodyne receiver principle. The strengths and weaknesses of this invention are important to the future of terrestrial TV broadcasting, so please read on ; you can quickly become an expert on superheterodyne receivers and amaze your boss.

Not Everything is 'Lost in Translation'
I recently attended and participated in the annual meeting of the National Translator Association, which is composed of TV translator operators. You might be surprised at their number.

Compression and Cross-Modulation
This column has been dealing with DTV-DTV interference and has almost completed this discussion.

Farewell to the Great CRT
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.

Sorting Out Reception Obstacles
The future is digital, 16:9 and gigantic. And I believe the future is now.

The Challenge of Channel Election
My research into DTV-DTV interference resulted in some interesting spectrum plots concerning third-order intermodulation (IM3) products as a source of such interference.

IEEE Symposium Highlights
By all accounts, the IEEE Fall Broadcast Technology Symposium was a success.

Anticipating Signal Behavior
In 1998, the FCC revised--for planning purposes--its desired-to-undesired ratios for DTV-DTV interference between adjacent channels (ACI). Originally, the D/U ratio was -43 dB, but now it is -26 dB in one case and -28 dB in the other case.

The Tide is Turning
Now that the FCC has established its timetable for broadcasters to elect which channel to return, I believe these same broadcasters will seek to maximize their DTV facilities.

DTV Interference Could Be Mitigated by Receivers
My previous column introduced readers to a new parameter, third-order intermodulation (IM3), which is the sideband splatter from a DTV transmitter into both adjacent channels.

Signal Distortion And Interference
Distortion comes in two basic classes: Linear distortion, which is not an oxymoron; and nonlinear distortion, which includes all other distortions except noise.

Whatever Happened to Reruns?
Ever since TiVo and ReplayTV blasted into the television environment, Madison Avenue and broadcasters have lamented that these devices will murder advertising, as users of these Digital Video Recorders (DVRs) skip through commercials.