Fiber optic video extender is an all-digital fiber transmission device, with world-class non-compression, all digital video correction technology and Gigabit fiber transmission technology. It supports long-distance, non-distortion and real-time transmission of 1~64 channels of video signal (and other kinds of signals if necessary) in one-core fiber optic.They are suitable to the purpose of monitor and surveillance in expressways, the customs, transportation, electronic police, industrial automation, power service, banks, and water conservation projects, etc…
At present, there are many types of video signals, such as HDMI signals, VGA analog signals, DVI signals, SDI signals, among these types of high-definition video signals, maybe SDI signals are not familiar in fiber telecommunication field. This article mainly tells you what SDI is, the common types of SDI video extender and application of SDI Video Extender.
What is SDI?
Serial digital interface (SDI) is typically used for digital, uncompressed, standard-definition video input and output. SDI is the highest-quality digital signal you can use for monitoring standard-definition video. All three signal components, Luma and the two color-difference channels (CB and CR), are multiplexed onto a single BNC cable. Due to the high bit rates, they are designed for operation over short distances.The most common data speed is 270 megabits per second (Mbps). However, speeds of up to 540 Mbps are theoretically possible. Standard 75-ohm cable is used. This is the same type of coaxial cable used in most home television (TV) installations.
SDI connections transmit uncompressed 720 x 486 （NTSC) or 720 x 576 (PAL) video at either 8-bit or 10-bit per channel resolution at up to 270 Mbps. SDI can handle both component and composite video, as well as four groups of four channels of embedded digital audio.
According to SDI connector, we often see HD-SDI and 3G-SDI video extender in the market.
As we all known, HD-SDI (High Definition Serial Digital Interface) operates at 1485 Mbps, which is more than fiber times the data rate of the SDI signal. Just like SDI, HD-SDI uses 10-bit samples and half as many color difference samples of each channel as compared to the number of luminance channels. The reason for the difference in bit rate is the much higher number of pixels in high definition video. Systems using HD-SDI are readily available, as are systems that use compressed HD digital video.
The design and production of HD-SDI video fiber optic extender is highly reliable, high-performance serial digital optical transmission equipment which is applicable to the television industry, its signal formats are from 19.4Mbps to 1.485Gbps, the system supports SMPTE292, SMPTE259M, SMPTE297M, SMPTE305M, SMPTE310M, DVB-ASI (EN50083-9) and other digital television signal format.
3G-SDI video extender is upgraded version of the HD-SDI, its signal formats are from 19.4Mbps to 2.97Gbps, the system supports compliance with signal SMPTE424M, SMPTE292M, SMPTE259M, SMPTE297M, SMPTE305M, SMPTE310M, DVB-ASI（EN50083-9）and other digital television formats.
SDI video extender over fiber system is an excellent choice for transporting SMPTE 259M, SMPTE 292M or SMPTE 424M compliant video signals over long or short distances with one fiber. In addition, the system support stereo audio, RS485 & RS232 serial data, Loopback output, Contact Closure and IP Ethernet transmission. New signals may be added or fully redundant optical transport solutions may be developed. applications include specialized Remote OB Van/Truck Video Feeds, Uncompressed Long-Haul Signal Transport, General Broadcast (News/Sports/Events), Broadcast Studio Camera Feeds, where long distance transmission of HD video signals are necessary, fiber optic transmission ensures high quality signals with no interference.
SDI standards have been introduced to support increasing video resolutions (HD, UHD and beyond), frame rates, stereoscopic (3D) video, and color depth. Dual link HD-SDI consists of a pair of SMPTE 292M links, standardized by SMPTE 372M in 1998; this provides a nominal 2.970 Gbit/s interface used in applications (such as digital cinema or HDTV 1080P) that require greater fidelity and resolution than standard HDTV can provide. 3G-SDI (standardized in SMPTE 424M) consists of a single 2.970 Gbit/s serial link that allows replacing dual link HD-SDI. As of August 2014, 6G-SDI and 12G-SDI products are already in the market, although their corresponding standards are still in proposal phase.