Technology Showcase: HD Fiber Transmitters
Nov 1, 2007 12:00 PM, By Bennett Liles
AV pros borrow from broadcast to expand their HD skill set.
While much has been written and discussed regarding the ongoing convergence of AV and IT, and as more AV products incorporate network connectivity and control, there has been less attention given to the dissolving line between AV and broadcast hardware. Heretofore driven largely by the emergence of IP networks in both the AV and broadcast industries, this convergence is currently accelerating due to the looming FCC-imposed deadline for the transition to digital television and the era of high-definition TV that will ensue. Therefore, there is a good deal of merit in viewing the movement as a three-way convergence. Even with existing compression techniques available, the bandwidth that HD video demands will drive us all toward fiber-optic connectivity.
Just as AV industry professionals have found it essential to learn and use the vocabulary, software, tools, and hardware of the IT world, it is increasingly obvious that because they will share the same HD boat with broadcasters, AV pros will also be going deeper into the realm of broadcast standards and hardware. In this article, we examine some hardware tools being used for studio-transmitter links (STL), video-production-room connection, and some distance-learning operations to send audio and digital HD video over fiber.
The hardware products covered typically conform to the SMPTE 292M standard, which is similar in scope to the previous SMPTE 259M, which deals with digital standard-definition video and 10-bit serial data rates up to 270Mbps. SMPTE 292M addresses the higher, full-bandwidth HDTV 1.485Gbps data rate, and with transmission distances ranging from more than 200ft. to more than 300ft., this is largely fiber territory. Versatility is a key to success in virtually any such product, and many discussed here support the SMPTE 310M standard for HD in an MPEG-2-compressed format at up to 40Mbps. A few also incorporate HD over IP networks, but that is a subject of interest to AV pros that we will examine in detail in a future article.
SMPTE 292M is currently used in hundreds of TV studios and video production plants to carry digital HD video signals between recorders, CG units, and other gear in close proximity (via coax) and across longer distances (via fiber). Among multiple stages of production, using this uncompressed video signal keeps the end product free of the artifacts that inevitably accumulate through multiple compression cycles.
In physical form, most of this hardware exists as rackmount units or slide-in modules, but just to keep things interesting, we also have spotted a few standalone and very small mobile products that extend this audio/HD video fiber transmission capability to the field. This is another indication that this stable of products, once exclusive to the broadcaster's toolbox, is finding its way into AV, and the spread of HDTV deployment will accelerate the trend.
Billed as the most installed member of the DV6000 family of multichannel optical transmission products from Artel Video Systems, the DV6016 interfaces 16 audio/video/data cards to a 2.38GHz time-division-multiplexed (TDM) digital stream. Card combinations can provide HD-SDI and multiple audio formats for 1310nm, 1550nm, CWDM, and DWDM fiber transmission modes.
Among the video-over-fiber hardware options offered by Broadata Communications is the 1100E, available as either a small standalone transmitter-receiver pair composed of the 1100E-TX and 1100E-RX or as a slide-in card in a card-cage system for transmission over multimode or single-mode fiber. The 1100E can handle ATSC, SDI, DVB-ASI, and HD formats, along with SMPTE 292M HD, SMPTE 259M SDI, and DVB-ASI signal regeneration. Front-panel LEDs indicate channel activity, and a loop-through function provides for video monitoring on the transmitter.
Monitoring and recording is available via two outputs on the receiver unit. In accordance with the needs of SMPTE 292M signals, data rates extend up to 1.5Gbps with a signal level of 800mVp-p plus or minus 10 percent. The Edge series of cards, released last year to support Broadata fiber-optic transport systems, incorporates an audio embedder and de-embedder; a digital-to-analog/analog-to-digital converter; and a 1:4 HD-SDI, SDI, and AES/EBU distributed amplifier. In the 200E-CC card-cage configuration, the 1100E has audio transmission capability added with the Edge-series cards.
Comlan Fiberoptic Solutions markets a variety of products that transmit analog, MPEG-2, MPEG-4, DVB-ASI, SMPTE 270M, and various data signals over fiber. A standard 19in. rackmount unit, the Comlan CL-1250VHD is primarily a Gigabit Ethernet transceiver, but the CL-1250VHD-1S-1V-2A-SMPTE-SC-80 variant also incorporates a high-speed data channel with the capability to transmit either DVB-ASI or SMPTE 310M compressed MPEG-2 video and two audio channels at 19.4Mbps up to 50 miles over fiber.
For video, the front panel includes power and link indicators, and the unit can be configured to transmit on one or two fiber strands. The fiber interface consists of standard SC or SC/APC fiber connectors. The unit can interface with single-mode and multimode fiber, and it autosenses 110V or 240V power.
For field production and tight places within racks, the EC3320T Racketeer single-channel, bit-rate-independent HD-SDI, SDTI, SDI, and ASI transmitter module and accompanying ECT3320R receiver module from Elcommtech is as small and mobile as it gets. Hardly bigger than the BNC connector on the input end, the ECT3320T accepts any of the named formats, with an equalizing input for compliance with SMPTE 292M, SMPTE 259M, DVB-ASI, or SDTI standards. The unit also passes embedded audio to 1310nm fiber at a typical output of -6dB. The module includes a 6V, 240mA power supply, and it features an LED indicator for loss of signal.
The ECT3320T-S-13 is the single-mode version, and the ECT3320-M-13 interfaces with multimode fiber. The ECT3320R receiver has a typical sensitivity of -3dB to -30dB, and it features the same loss-of-signal LED indicator.
The Model 3762 digital broadcast transmitter from Emcore transmits digital HD video using MPEG-2 compression (SMPTE 310M) with up to 16 pre-embedded audio channels, as well as DVB-ASI standard-definition digital signals and analog audio, on a single fiber. This is done through a customized mix of hot-swappable, field-installable slide-in modules held in three rear-access mounting bays. One of these bays holds the module to supply power for the optical terminal and the other custom-configurable modules. A CWDM option expands the fiber transmission parameters by combining up to eight wavelengths on a single fiber.
Front-panel system monitoring includes five LED indicators and a 20-line, 20-character LCD display screen. A DB-9 alarm interface on the rear of the unit allows users to set up a remote alarm for both transmitter and receiver. Among the many options for slide-in module customization is SMPTE 310M-to-DVB-ASI conversion.
The Evertz Microsystems 7707ADVT-HD transmits uncompressed SMPTE 292M digital video at 1.485Gbps with analog-to-digital and digital-to-analog audio conversion. The unit also handles composite analog or SDI digital video. The 7707ADVT-HD also uses VistaLink, the Evertz SNMP realtime configuration and monitoring platform for transmission on single- and multimode fiber. This is accomplished on 1310nm, 1550nm, and up to 16 CWDM wavelengths. DWDM wavelengths are also available. The unit occupies a hot-swappable card slot, which can be changed from the back to the front of the frame with no fiber disconnect/reconnect required. The receiver is the ADVR-HD single-card unit with complementary capabilities along with adjustable gain, DC offset, and pre-emphasis for driving up to 800ft. of Belden 1694 coax.
Among the recent expansion in fiber products from Extron Electronics is the Fox HD-SDI fiber-optic extender for single-fiber transmission of SDI, HD-SDI, and 3G-SDI signals with embedded audio. Configurable as a transmitter or receiver, the unit is marketed for digital signage, broadcast and production, rental and staging, and telemedicine. For local building runs, the Fox HD-SDI MM is used at 850nm on multimode fiber, while the Fox HD-SDI SM transmits at 1310nm over single-mode fiber for distances up to 20 miles. Dual buffered outputs enable the extender to be configured as a dedicated transmitter and to display the output signals on a local monitor. The extender can also be configured as a dedicated receiver with daisy-chain capability to carry the signal from a single transmitter to multiple locations.
Fibridge offers the HD-SDI/SDI/ASI Optical Transmission System in either hot-swappable rack-module or standalone versions for single- or multimode 1310nm/1550nm fiber transmission of serial digital video from 19.4Mbps to 1.485Gbps plus audio for up to 50 miles. Marketed primarily for CCTV and video surveillance, the unit provides three input ports and three 800mV output ports. Two of these are for transmission, while the third output port is a local loop out for monitoring. The system also features remote console management via SNMP or the Web.
Harris Broadcast offers the HOS6800+ and OHS6800+ transmitter/receiver pair as the solution for SMPTE 292M HDTV, SMPTE 259/297 SDI, or DVB-ASI and embedded audio over single-mode fiber with an output wavelength of 1310nm. For monitoring and other uses, the devices provide two equalized and reclocked electrical outputs and automatic and manually set reclocking modes. Card-edge LEDs provide monitoring of input signal presence and the reclocked data rate. Included is the CCS+Pilot Lite application for PC-based remote status monitoring and control. The OHS6800+ can support input wavelengths from 1260nm to 1620nm.
The Maxcom Fiberoptic Products MX3257HD fiber-optic video multiplexer can be wall-mounted or rackmounted, and it transmits one channel of video, two channels of audio, and one high-speed data channel directly to a single multimode or single-mode fiber-optic line. The high-speed data channel can carry either DVB-ASI or SMPTE 310M MPEG-compressed high-definition video at 19.4Mbps.
The MX3275HD features an internal power supply and front-panel LEDs that indicate power and link activity. It uses automatic cable equalization for long-input coax runs, and it transmits digital stereo sound. The external audio input signal may be either balanced or unbalanced. The unit is available in several variants for specific formats and applications depending on the high-speed data channel format and the transmission distance desired. The product is used as a transmitter/receiver pair.
One of the smaller, mobile solutions in this transmission arena is offered by Meridian Technologies in the form of the DigiView HDT/R line of miniature serial digital video transmitters and receivers. The units can work with SMPTE 292M, 310M, 259M, and 344M on multimode or single-mode fiber with embedded audio support. The product is also available in a rackmount configuration with the Meridian desk/shelf-mount chassis or in 19in., 3RU racking frames. The units include LED indicators for power, receive optical power, transmit video-signal presence, and laser over current. They are also available with CWDM lasers for 16-channel mux over one fiber. The incredibly small units measure 3"×.75"×.6" and weigh a mere 1.5oz., making them capable of being plugged directly into a field camera.
The compact HD-1500 from Multidyne provides a solution for SMPTE 292M HD, and SMPTE 310M standards from 5Mbps to 1.485Gbps with embedded audio in a rackmount or standalone form. With dual reclocked outputs and buffered loop-through, up to six units can be grouped together in a 1RU space. Applications include video editing, video production, ENG, and computer networking. Transmission distance is up to 12 miles on single-mode or up to 1000ft. on multimode fiber.
Opticomm offers a rackmount solution to HD-SDI fiber transmission with the Optiva OTS-1HD2DA. Available as a hot-swappable slide-in card for a 19in. rack of a smaller desktop rack, the unit provides one channel of HD-SDI SMPTE 292M uncompressed video with loopback and two channels of AES/EBU digital stereo sound. The output uses TDM for single-wavelength fiber-optic transmission, but it is compatible with the Opticomm MDM-7000 series for WDM and CWDM multiplexing.
The video input sources interface with gold-plated BNC connectors while the audio signal attaches to a Micro DB-25. The OptivaView SNMP management suite allows for remote monitoring, bandwidth management, alert notification, and an alert log. In addition, the suite can be used with any SNMP user interface. The controller card occupies 1RU, and it can control and monitor all installed Optiva systems in the same chassis.
The OPV1200 series from Opvision Technology transmits one channel of SDI or HD-SDI in SMPTE 259M, 292M, and 310M from 19.4Mbps to 1.5Gbps, along with four AES3 audio channels on single-mode or multimode fiber depending on the specific variant ordered. Available in a rackmount, card-cage, or standalone versions, the OPV1200 includes LED indicators for video and fiber-optic signals along with power and malfunction indications. The video input interface is a 75Ω BNC, the fiber connections are FC/ST/SC, and the standalone version includes a 5VDC, 2.4-amp power supply.
Currently in final beta testing for marketing early in 2008, the Stratos Optical VMAES-H-B-X-X 4-channel AES audio embedder/de-embedder is the company's latest product offering. It transports SMPTE 292M, SMPTE 310M, and DVB-ASI video; embeds/de-embeds four AES audio streams into/from HD (SMPTE 292M/297M) video signals; and offers extended distances via fiber.
Controllable through a local keypad and OLED display or remotely over a web-enabled Ethernet port, the unit uses ST fiber connections or 2- or 4-channel bulkhead single-mode expanded-beam connectors for optical inputs and outputs. When operated in embedder mode, the device allows the AES audio signals to be either synchronous or asynchronous to the HD video signal. The web control feature allows remote adjustments in operating mode, traffic type, audio status, and level, as well as optical transmit and receive parameters.
In addition to its formidable stable of field production fiber transmitter/receiver products, Telecast Fiber Systems markets the Viper II, a digital AV fiber transmission system consisting of a 3RU rack cage with up to 16 custom-configurable slide-in cards. The slide-in modules can convert to standalone units housing one transmitter or receiver function in wall-mount, tabletop, or “throw-down” form.
The TX/RX5292 is the serial digital video interface transmitting at up to 1.5Gbps SMPTE 292M video. In the rack configuration, audio and data modules may be used for any combination of transmission capability, and any card can fit any slot in the universal mounting frame. The PS5000 power module is autosensing, and the PS5010 alarmed UPS module is also available for 10 to 30 minutes of emergency power. The system is intended for use sending serial digital video between rooms, floors, and buildings in any form necessary, including uncompressed HDTV in cases where compression artifacts may be a problem.
Among the products in its Ventura line of modular point-to-point fiber-optic transports, the VS254-E-SFP from Video Products Group is an HD-SDI audio embedder and optical transmitter card that puts four AES audio channels into the 1.5Gbps serial datastream and outputs to its SFP optical connections supporting 1310nm, 1550nm, CWDM, and DWDM.
The unit features full CRC and EDH error checking in HD-SDI and SDI modes along with a built-in HD-SDI test signal generator. The device also includes onboard switches and remote SNMP or web-based monitoring and management for all card functions. Power supplies for the Ventura series include the VS101 three-slot chassis with integrated power supply and optional network management, the VS103 10-slot chassis with either AC or DC dual redundant power supplies, and the VS113/123 auto-ranging power supply for the 3RU Ventura chassis. The VS254-E-SFP occupies only one slot in either the VS101 or VS103.
Bennett Liles is a freelance television production engineer and AV technician in the Atlanta area. He specializes in government video production, distance learning, and videoconferencing.
For More Information
Artel Video Systems
Comlan Fiberoptic Solutions
Maxcom Fiberoptic Products
Multidyne Video and Fiber Optic Systems
Telecast Fiber Systems
Video Products Group
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