Transitioning from analog to digital opens new doors, including one to multichannel operations. The bandwidth freed within the digital realm makes multichannel broadcasting an attractive option for building revenue through additional program streams.
Digital System Technology’s (DST) most recent multichannel system project is integrating San Francisco station KBWB-TV. The station owner, Granite Broadcasting, hired DST in 2002 to work with station engineers on ways to improve cost-efficiency, reliability and on-air quality.
A preliminary study
DST began with a comprehensive study of the station’s analog operation, focusing on reducing operational costs by eliminating cumbersome processes. The station’s lack of a news operation enabled DST to shift its focus from production to program acquisition through playback processes. The study encompassed the station’s complete workflow process, from the initial receipt of media all the way through to air.
In the next stage, DST thoroughly researched technology and vendors for the best solutions, and the station made the final vendor selection. The team determined that comprehensive automation would be the best way to streamline operations and improve the station’s on-air look, reducing inaccuracies attributed to labor-intensive manual processes. By automating and tightening workflow, the station could reduce the risk of losing commercial spots and create cleaner transitions between programming and station breaks for a more consistent and pleasing on-air look.
The project focused on replacing aging analog master-control and ingest systems with a new digital master-control center, 10 associated equipment racks and a server-based ingest suite. Digital video servers replaced the station’s analog videotape-based systems for interstitial and long-form playback. An automated on-air delivery system reduced operational costs and established a clear signal path for three channels, including one that could accommodate a high-definition channel.
KBWB continued broadcasting in analog as DST began work in an existing area designated for the digital master control and its technical core. DST built all equipment racks and systems on-site. Installers installed color-coded, HD-upgradeable Belden 1505 wiring so that signals can be identified readily throughout the facility as digital video, analog video and digital audio.
A Sundance FastBreak Automation system handles all master-control equipment central to the on-air output. A Miranda Presmaster 2 master-control switcher and Imagestore channel-branding system are integrated to accommodate automated multichannel operation. An SDI Leitch Integrator system routes signals into the Presmaster 2 for switching and the Imagestore for keying and insertion of stills, logos and other graphical elements. A signal path links multichannel streams with the microwave system for distribution. An existing KTech Preformer HD switcher upconverts the HD stream.
Rather than manually pushing buttons for transitions, the master-control operator essentially plays a supervisory role in relation to the on-air product, including programming ingest, signal monitoring and other media management issues. In the event of automation failure, a Leitch 16x1 bypass switcher can accommodate manual operation with the press of a button.
Other master-control systems include a Chyron MAX CG and an Ikegami monitoring wall consisting of separate color and black-and-white monitors set up on adjustable shelving for easy reconfiguration. An Omneon SPECTRUM server sends audio into the Imagestore system for synchronization with the program stream.
Two Tektronix SPG422 sync generators synchronize all master-control equipment to avoid on-air glitches. A Tektronix changeover switch automatically switches to the backup unit if the main system fails.
The existing analog terminal-gear room on the other side of the master-control wall remains intact to accommodate analog streams within the system. Ten equipment racks in master control accommodate several VTRs and Leitch terminal equipment, including analog-to-digital and digital-to-analog audio and video converters, and audio and video DAs.
The digital and analog terminal-gear equipment connect in a separate room. Special tie lines connect the Leitch Integrator digital router and the analog system — each equipped with a corresponding A/D converter — to enable master control to input analog signals. Eventually, the station will remove these tie lines and the analog core as analog signals disappear from the system. The current 32x32 digital router is wired for 64x64 to accommodate future expansion.
The audio portion of the digital routing system features two layers of AES digital audio. This is unusual for many stations, but the additional AES layer allows the facility to produce four channels of audio and perhaps offer a second language for its broadcasts. This can be especially useful for San Francisco’s multilingual viewership. An Intelli-Sat satellite ingest system controls existing KTech satellite receivers that receive and automatically record feeds coming into the Omneon video server. Snell & Wilcox IQ modular frame synchronizers condition incoming satellite feeds before the feeds proceed to the router.
Three new controllable satellite dishes on the facility’s roof interact with Intelli-Sat, allowing the ingest station to receive satellite feeds with minimal human operation. The dishes also feature a narrower angle of reception compared to the previous models, lowering vulnerability to interference.
The ingest station occupies a separate room close to master control. This room also serves analog ingest, although Omneon video servers and a Sundance automation system (comprised of two prep stations and two air stations) have automated and simplified tape operations. Operators use the prep stations to ingest programming into the video servers, create playlists and finalize on-air schedules. The air stations recall programming from the servers and play broadcast materials out to air.
The room supports two ingest formats. The existing ingest system remains intact on a smaller scale and features several small analog video servers (DG System, Vyvx, Pathfire and Media DVX) and tape machines. These devices were rewired and integrated with analog-to-digital converters to feed the digital ingest system. The Omneon video servers comprise the heart of the new ingest format and tie into the Sundance system to provide storage. The servers replace several VTRs. The VTRs still in service consist of DigiBeta, Beta SP and one-inch machines. The ingest room console also includes color and black-and-white monitors used to QC program materials as they are recorded. One person can handle the entire ingest operation at most times.
KBWB is currently using only its main channel but is fully prepared to move forward with multichannel broadcasts and take advantage of the cost and operational efficiencies offered by its modern automated system. Thanks to a wealth of modern digital equipment, the station is on its way to using its newfound bandwidth.
Jeff Muhleman is vice president of contracts for Digital System Technology.
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