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Network serves research and education projects.

Network Serves Research and Education Projects

The Microelectronics Center of North Carolina (MCNC), a nonprofit corporation located in Research Triangle Park, was established as a unique national resource for integrated microelectronics research and development. It serves as a neutral education and research center where all parties addressing the future of microelectronics can work together to meet the technical challenges that lie between basic research and manufacturing reality.

The center offers industry participation in all phases of advanced integrated-circuit manufacturing technology, including the basic and applied research performed at its Central Laboratory and six participating institutions: Duke University, North Carolina A&T State University (NCA&T), North Carolina State University (NCSU), University of North Carolina at Chapel Hill (UNC-CH), University of North Carolina at Charlotte (UNC-C), and the Research Triangle Institute (RTI).

MCNC provides an industrial-type research center for use by the university community and industry, coordinates a variety of university support programs, and conducts a coherent integrated program of research in microelectronics. The center supports interdisciplinary research and education and structures joint university-industry projects. A 10,000-square-foot ultraclean fabrication facility is being developed to process and fabricate submicron microelectronics chips for utilization in advanced manufacturing research and testing.

Objective: National Leadership

The center's primary objective is to develop national leadership in the area of high technology and microelectronics. Its working relationships bridge the gap between the industrial production environment and basic research being conducted by the university community. Whereas ordinary university centers do basic and applied research and industry is concerned with design and manufacturing aspects of production, MCNC, along with its industrial affiliates, fills this gap between research and production. Its program speeds the transfer of information and technology from the research community to high-technology industry.

To permit timely participation in research and education projects throughout the consortium, the center has installed an extensive communication network that provides transmission services for video, audio and data traffic. The MCNC communications system interconnects the six participating institutions with the Central Laboratory so that participants can interact through videoconferences, teleclasses and data exchange.

The primary functions of the system are to provide videoconferencing, teleclasses, voice interaction and digital communications throughout the MCNC community. The network has been designed to provide real-time, interactive capabilities. The network extends from NCSU at Raleigh westward to UNC at Charlotte, a distance of 152 miles. The network also interconnects Duke in Durham, UNC at Chapel Hill, NCA&T in Greensboro and RTI in Research Triangle Park.

In addition to the existing network, a project to extend the network to include UNC Asheville, Winston-Salem State University, Bowman Gray School of Medicine and the Center for Communications Signal Processing at NCSU is under way, with projected completion by the summer of 1987.

The network provides extensive video and data capabilities. Two duplex analog television channels are shared among all the institutions. The digital channel of 16 Tl channels provides substantial capabilities for computer networking, data transmission and research. The digital bandwidth has been allocated among many services, including Tl compressed video, and these channels will enable the network to provide more video services beyond that of the two analog channels.

The MCNC communications system consists primarily of microwave hops between the participating institutions and the Central Laboratory. Harris (Farinon Division) DM2-16-25 digital microwave radios are used for the digital transmission path. The vendor's M1-2 multiplexers break out the 25-Mb/s data path into 16 individual Tl (or four T2) circuits, and its broadcast video transmitters provide the video channels between the participating institutions and the laboratory.

The video is transmitted via narrow-band FM (10-MHz bandwidth) in the 6-GHz OFS (operational-fixed service) band. The data is transmitted via 2-GHz OFS frequencies using 10 MHz of bandwidth. Network specifications are based on a 54-dB signal-to-noise ratio for the video transmissions from end-to-end (RS 250B), and a 99.99-percent reliability. The digital transmission of 25 Mb/s is standby-protected and was designed to provide a maximum bit-error rate of 10(-6) from end-to-end. Actual testing has indicated a performance in excess of 10(-10). The RTI-MCNC microwave link is a 23-GHz M/A-Com system that consists of a full-duplex analog video channel and a T2 (four Tls) digital microwave channel.

While the backbone network utilizes microwave technology, the network uses fiber-optic links to interconnect the laboratory facility to the primary microwave tower in the research park. The interconnect is a Siecor-FiberLAN mono-mode 28-fiber optic cable and associated fiber-optic drivers and receivers. Each analog video signal uses a separate fiber for transmit and another for receive. Since nine video signals come into the laboratory (two from each of the four primary microwave hops and one for the RTI microwave link) and go back out, 18 fibers are used for the video interconnect alone. The digital circuits are multiplexed into a 45-Mb/s signal and transmitted over a pair of fibers.

The video network is designed so that a video program can be received at the laboratory and sent on to as many of the other sites as desired. The video switching system has the flexibility to provide concurrent point-to-point switching so that several programs can be transmitted simultaneously over different portions of the network. It's not unusual to have both video channels operating concurrently and provide a third point-to-point program for other institutions.

The data network provides point-to-point circuits and networking. The point-to-point circuits are synchronous and asynchronous and operate at speeds from 9.6 kb/s 1.5 Mb/s.

The two duplex video channels are used to transmit graduate courses in microelectronics and for research and education videoconferencing. Each campus has installed a teleclass facility for origination and reception of courses and a full-motion videoconference room for research and education videoconferencing. The videoconference room and the teleclass room are interconnected to the microwave radios by the campus local-area network (LAN) system.

To assure commonality of equipment and consistency of quality from campus to campus, MCNC initially purchased all the video and audio equipment to be installed on each campus. The campuses are responsible for supplying the physical facility, installing the equipment and operating the video facilities.

The facility was designed so that a common control room could serve both the videoconference and teleclass rooms. Some equipment, such as a sync generator, waveform monitor and vectorscope, could be used to monitor both rooms without affecting the operations or quality concerns. In addition, the common control room reduces the operational staffing requirements.

Teleclass Rooms Vary in Size

The teleclass room varies in size according to individual campus requirements. Typically, the room seats about 30 to 40 students. The instructor either sits or stands at console in the front of the room. Four video cameras are used. Two are at the back of the room for focusing on the instructor. The third is used as an overhead camera for graphics. The fourth camera is used to pick up student questions when the professor is located at another campus; the instructor and student can have a discussion on a real-time interactive basis. Two nine-inch video receivers are installed into the instructor console so that the instructor can see the outgoing broadcasts and the output from the graphics camera.

The overhead camera is used to pick up notes, diagrams and graphics used by the instructor. The instructor can operate the pan/tilt and focus/zoom at the console, if so desired. The teleclass video producer normally operates the remote control and selects the camera shot, although this can also be handled directly by the instructor.

The room was designed to eliminate the need for a blackboard. Instructors are encouraged and assisted in using pre-cut white boards, overheads and prepared graphics, and the system is sufficiently flexible for yellow legal pads to be used effectively. All graphics information is put on large monitors (46-inch rear-projection) for both the origination and receive classrooms.

Normally, each originating institution video tapes the teleclass for makeup and review. If technical difficulties preclude one campus from participating in the teleclass, the tape is made available for review. Currently, 10 graduate courses in microelectronics are being transmitted over the network.

The Videoconference Room Setup

The videoconference room was designed to handle six participants per site. Up to six additional participants can view the conference by sitting in a second row of chairs. A curved table was selected because it provided the best angle for viewing and for conferencing.

Participants face three 25-inch monitors to view the conference. Alongside the monitors are six video cameras. Each of the cameras is prefocused on one of the six participants. The seventh camera provides an overall shot of the entire table. An eighth camera is used for overhead graphics and illustrations. Immediately in front of the center two chairs is a control panel that's recessed into the table. The lift-up panel provides local control of the conference room.

All cameras except the one overhead are controlled by microphone switching system made by Shure. The overhead camera is manually selected by the conference leader or the person in the control room. As each person speaks, the camera that's prefocused on that individual automatically turns on and his/her image is transmitted to the other sites. If two or more people talk and/or interact simultaneously, the system automatically switches to the overall group shot. It should be noted that all this can be overridden manually by the conference leader as desired.

Since the communications system has been designed as a modified star network, it's possible that multi-site conferencing can take place. For all seven initial sites to see, hear and interact with every other site in the system complicates the switching complexity of the system, but it does provide for community-wide participation by treating all sites as an origination site.

Several sites can be viewed simultaneously at MCNC. Although it isn't possible to provide additional video channels between the participating institutions, it is possible to provide each site with several images simultaneously by using a quad splitter. The quad split takes four video images and compresses them into one video image. The four video signals are selected by MCNC Network Control and are sent to the other conferencing sites. This gives the other sites a view of four of the other conference members simultaneously and, over the duration of the conference, this mix is changed several times so that each site sees everyone involved in the conference several times.

Videoconferencing has been available on a limited basis (several campuses have not completed their videoconference facility) to members of the MCNC community since June 1985. In the first seven months of operation, 98 conferences were held, involving over 1700 people.

The audio for both the teleclass and videoconference rooms is full duplex, wideband and ungated. All sites are fully interactive and can participate simply by speaking. Since the system is not gated, nor are people "locked out' while someone else is speaking, interaction occurs spontaneously. This accomplishment has been difficult. The complexity of the system and the full-duplex capability reduces any margin for error. The rooms have been acoustically treated and equalized for optimum sound. The audio transmission line is wideband 20 Hz to 15 kHz and is transmitted digitally, so there's little degradation. Some compression is employed and there is a limiter to prevent over-modulation.

Additional Audio Measures Taken

The potential for feedback required that additional measures be taken. First, all audio signals are fed directly to Network Control. Because of the live, interactive nature of the programming, the audio is mixed and sent back to each site. To reduce some of the feedback problems, a special audio console (designed and built by Logitek) automatically provides a mixed signal back to each institution minus its own signal. This has been extremely useful for controlling most of the feedback. In addition, it has reduced setup time considerably and has proven to be essential for quality control and network management. The console can be reconfigured in a matter of seconds. The end result is that the audio is clear and unobtrusive and everyone can earily participate.

MCNC Network Control serves as the switching center and quality-control center for the network. Since all the programming is live, all programs are switched on a real-time basis, which means that video switching must take place within a very short time period. This is further complicated by the fact that one video switch may actually involve all seven sites, with all seven receiving the new signal. Since the network can be configured in a number of ways, a computer-driven switcher was essential. Hedco designed the network video switcher, which is driven by an IBM PC. The Hedco switching system includes two 15-position "shot' boxes, which are basically pre-sets that can be configured by the PC. Since each program and videoconference often involves a different mix of institutions, the network and shot boxes are reconfigured 10 to 12 times per day.

During a videoconference or teleclass, all switching is done by selecting one of the pre-sets, and all of the switchers, including those located at each campus, are automatically switched. Thus, when a question is raised, Network Control can switch that video to all other sites within one second. In addition, the switching system is used to isolate problems by "folding' back a video signal at various points throughout the network so that the problem area can be determined.

The other primary role of Network Control is that of maintaining standards and video quality throughout the network. All video signals are routed through synchronizers for glitch-free switching and for signal adjustments. Readings of video signals from each campus are logged in daily and monitored through appropriate vectorscopes, waveform monitors and broadcast monitors. Signal variances and troubles are quickly identified for resolution. Network Control is in constant contact with operators and video managers throughout the network via a specially designed order wire.

The Backbone Microwave System

The backbone microwave system is a modified turnkey installation by Harris/ Farinon. Farinon was responsible for all transmission equipment, from radios and waveguide to antenna systems and installation. MCNC staff handled construction of towers and buildings, conducted path analyses, and installed monitoring, control and related equipment. Although the deadlines for installation and operation were quite short, the system went on line as projected. The first phase of the system was operational on January 7, 1985, and the first teleclass was broadcast on January 9. The RTI-MCNC microwave link was installed as a modified turnkey system by M/A-Com.

As the accompanying map illustrates, planning is under way to extend the system farther to the west and southwest. These extensions should be operational in the summer of 1987. Videoconference and teleclass rooms will be established at each of the new locations. Compressed digital video at the T1 rate will also be installed for transmission of additional video courses and conferences. While the final design for the digital video network has not been completed, it's hoped that the network can be switched directly by the originating institution.

The extension to the Bowman Gray School of Medicine in Winston-Salem and the interconnect to the Center for Communications Signal Processing at North Carolina State University will initially involve high-resolution image processing. Since the immediate community also includes the Duke Medical Center and the UNC-Chapel Hill Medical Center, the potential for high-resolution image processing research is substantial. This potential, when coupled with the unique state-of-the-art transmission facilities of the network, provides a unique national research environment and base for image-processing developments. The research areas include x-rays, nuclear magnetic imaging, CAT scans and other high-resolution images.

Industries Give Funds, Expertise

Because of the complexity of the communications technologies used by the communication system and the high attendant costs of equipment, the development of the network as involved close association and support from industry. Several industries have provided funds, equipment or expertise to assist in the development. These industries and businesses are: Branch, Banking and Trust, Central Carolina Bank, First Union National Bank, The General Electric Foundation, General Telephone of the SouthEast, IBM, Lowe's Companies, M/A-Com, NCNB Corporation, Piedmont Airlines, RCA, Siecor Corporation, and Wachovia Bank and Trust.

The end result is a network that provides the MCNC community with unique research resources.

Photo: The MCNC network has extensive video and data capabilities.

Photo: The current network is being extended westward to add more participating institutions to the system.

Photo: Henry Morrow, communications engineer, at the MCNC microwave radio facility.

Photo: Gene Bradley, Duke video manager, is producing a teleclass.

Photo: Donald Loveland is conducting a teleclass at Duke.

Photo: Andy Brawn, production specialist, is monitoring video quality and switching.
COPYRIGHT 1986 Nelson Publishing
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1986 Gale, Cengage Learning. All rights reserved.

Article Details
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Author:Blatecky, Alan
Publication:Communications News
Date:Apr 1, 1986
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