NBC News Channel Turns to FM Systems VM-771
 |
Buyers Guide Reprinted from February 1994 |
USER REPORT
NBC News Channel Turns to FM Systems VM-771
By Richard Yeats Senior Producer of Operations NBC News Channel
CHARLOTTE, N.C.
If there is anything the major news gathering organizations have learned over the past few years, it is that coverage of world events is no longer purely prime time, but in fact, anytime. Viewers and listeners insist upon news 24-hours-a-day. To that end, the major networks have attempted to match the demand and remain competitive by increasing their affiliate news services.
NBC News met the challenge by building the NBC news channel in Charlotte, N.C. A multi-million dollar facility, the NBC News Channel serves as a central hub for the collection and distribution of national and international news stories for NBC affiliates.
It also produces the overnight NBC newscast “Nightside,” and most recently began distributing a 24-hour cable Spanish-language news service, Canal De Noticias.
STAYING ON TOP
The NBC News Channel, like its competitors, depends heavily on technology to gather, process, and transmit its product in a timely fashion. The latest in satellite uplinks and downlinks, tape machines, and video processing equipment all come into play. In an effort to stay on top of the game, we’re constantly looking for a better way to do what we do., which brings me to the subject of this article… the VM-771 Video Master by FM Systems.
With all of the feeds coming into the NBC News Channel INTAKE area at any given time, there are never enough people to monitor all the feeds all the time. We needed a way to help ensure better quality control in an effort to avoid refeeds. The Video Master has been of great help.
The VM-771 is a baseband video processor that stabilizes video levels, clamps out low frequency interference, and automatically corrects luminance-to-chrominance inequality. There are no adjustments or controls on the outside of the MV-771 box, making it a less-likely candidate for “tampering.”
The box housing the unit takes up very little rack space, with video and power connectors on the back and a green “VIDEO ON” LED on the front.
The NBC News Channel application places the Video Master in the video chain between the router output and the VTR input. Virtually all feeds to the News Channel pass through the INTAKE area and are thus passed through Video Masters. Because feeds to the News Channel come from so may sources around the world, we needed some way to backstop the operators and ensure more quality control. The Video Master does just that.
OPERATING FUNCTIONS
The VM-771 can do any of the following, according to the operator’s manual:
- Automatically gain-regulate sync level to 40 IRE units.
- Automatically gain-regulate white level so as not to exceed 100 IRE units. White level is not clipped, but retains a linear scale.
- Regulate output level to 1 volt peak to peak (at 100 percent white level).
- Automatically correct luminance-to-chrominance ratio, thus compensating for cable slope loss or other sources of high frequency attenuation.
With back porch clamping, eliminate all incoming low frequency interference such as 60 cycle ground loops even when the video signal is removed, and cancel low frequency distortion in the video signal.
Before placing a Video Master online, we handed it to our engineers (with all the promises of the operator’s manual) and asked them to put it through some bench tests.
They reported back that it held up to its promises. But among things that could be improved, they requested the ability to pass video should power to the unit fail. It’s a small item but worth mentioning.
And because the unit rides levels relative to sync, another concern was that if the unit was fed a signal with low sync but white levels exceeding 100 IRE units, the white levels would exceed desirable levels when it gain-regulated the sync back to 40 IRE units. The final comment, at least for our application, was that a white clipper would make the unit near perfect.
But quite frankly, for the price, this unit couldn’t be much better. It receives high praises from the NBC News Channel.
Editor’s note: Richard Yeats has worked with the News Channel for three years, and with NBC for eight years. Prior to arriving in Charlotte, Yeats worked in NBC’s Burbank bureau.
The opinions expressed above are the author’s alone. For further information, contact Tom Corwin (Phone: 800-235-6960; FAX; 714-979-0913), or circle Reader Service 45.
