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Network Electronics equipment Optical equipment of Network Electronics ASA Company (Norway) presented by the Flashlink Series product line. It designed for transmission over Fiber Optic link all types of signals: broadcast, telecommunication and multimedia ones. The equipment positioned by manufacturer as professional and is recommended for use in applications requiring maximum quality and reliability upon developing information exchange with use of Fiber Optic links. Wide product range, their modular structure and flexible company’s pricing allow solving tasks of signal transmission over Fiber Optic links at minimal cost. It is important to mark that optical and distribution equipment of Network Electronics Company of Flashlink and Vikinx Series is certified in Russian Federation according to “Svyaz” system and complies with GOST R ISO 9001—96 and with technical requirements to the equipment of television cable distribution networks agreed by Russian Communication Ministry on July, 24, 1096. It also complies with Rec 45.059—99 “Technical requirements. Equipment and systems of synchronous digital hierarchy transmission”. Manufacturing base of Network Electronics is certified on ISO 9000/AQAP 120 standard. All Network Electronics’ equipment has 3 year warranty. Service and technical support provided by the certified service center in Moscow. Flashlink Series optical equipment supports most popular modern signal formats, both digital and analog. All signal types can be transferred over Fiber Optic link with the use of WDM technologies (two channels), CWDM (up to 16 channels) and DWDM (up to 40 channels).Product line includes also optical multi band transponders and optical combiners (splitters, dividers). It is possible to use 8-channel multiplexing for AES signal transmission via the same wavelength. Firmware GYDA management system provides wide possibilities of remote monitoring and control of all Network Electronics equipment. Flashlink Series devices operate both with digital and analog signals. What is special about this equipment is that for transferring via Fiber Optic links the only digital signals are used. For analog video and audio signals transmission the electronic-optical converters are used having function of A/D pre conversion of electric signal. At the receiving side after optical-electrical conversion the back conversion of digital (SDI for video and AES for audio) signal to analog shape. For video signal 10-bit 4:2:2 A/D conversion is performed. Digitizing of component and composite NTSC and PAL signals is possible. For quantization error reduction 27 MHz quantizing frequency is used with further averaging on amplitude and decreasing quantizing frequency to standard for SDI 13.5 MHz value. Announced by manufacturer S/N ratio for optical transmitter with ADC is not less than 60 dB (not weighted). Such approach to transmission of analog signals has the obvious advantage — the S/N ratio for analog signal at its transmission over Fiber Optic link in digital shape has unchangeable value independent of a value of link’s optical budget. In a case of direct modulation of laser by analog signal the S/N ratio degrades when the loss in link go up. The Flashlink Series product range includes converters for the following signal formats and bit rates for their transmission:
Indexes: OE — optical-to-electrical; EO — electrical-to-optical; D or D15xx — for DWDM Since the description of converters for G.703 standard is off topic for the Magazine 625 than in the present article they are not considered.
SDI-OE is an optical-to-electrical converter which is able to operate on 19.4…540 Mbit/s bit rate. It is equipped with built-in distribution amplifier with two outputs. On optical input wideband technology on Pin diode is realized. High device sensitivity (-30 dBm) allows signal transmission on distance up to 150 km (SDI-OE-L model). A version for signal transmission on midsize and short distances (SDI-OE-S) has sensitivity not less than -20 dBm. Converters are supplied with SDI-EO-C1 connectors’ module. Input level for SDI-OE converters is -6 and 0 dBm for SDI-OE-S and SDI-OE-L models respectively; wavelength — 1200…1620 nm; output signal level — 800mV. SDI-EO is a converter of electrical SDI signal to optical signal with the similar to SDI-OE bit rate. Built-in cable equalizer provides a correction of high quality coaxial cable with length of 300 m at 270 Mbit/s bit rate. Optical output realized on laser Fabry-Perot diode (for 1310+40 nm wavelength) or DFB laser (for 1550+40 nm of 1479+6…1610+6 nm band for CWDM). Input impedance of a converter is 75 Ohm; input signal level — 800mV. On optical output -7.5 or 0 dBmV power is provided depending on modification. Reflected power level doesn’t exceed 4%. SDI-EO-D is used in a case when after conversion DWDM multiplexer is used. On the output DFB laser is used and on input — built-in cable equalizer.
Electrical-to-optical AES-EO converter provides transmission of digital AES/EBU audio signals over Fiber Optic link. It operates with reverse AES-OE converter and allows reaching transmission distance of 60 km. Besides, having limitations of cables use it is possible device operation in conjunction with WDM, CWDM or DWDM multiplexers. Optical output realized the same way as at SDI-EO. Installed on the receiving side optical-to-electrical AES-OE converter is based on PIN diode at input and receives signal in 1200…1620 nm band. On balanced transformer supplied output with 110 Ohm impedance AES-3 (AES/EBU) signal with jitter not more than 20 ns is formed. HD-EO/OE devices differ from their standard definition “brothers” by higher maximum bit rate — up to 1.485 Gbit/s which is absolutely necessary for operation with HD-SDI signal. On optical output of HD-EO laser Fabry-Perot diode is used generating light signal with 1310 nm wavelength or DFB laser (1550 nm) which is required for signal transmission on long distances. Device’s input is equipped with cable equalizer and built-in distribution amplifier with two outputs. Output power level is -7.5 or -3 dBm for 1310 nm or 0 dBm for 1550 nm. Wavelength deviation doesn’t exceed ±20 nm. OE converter has sensitivity not less than -20 dBm when receiving signals with 1200…1620 wavelength. Device is supplied with distribution amplifier with two outputs. SDI-TR-D15xx is an optical converter-transponder providing various formats signals conversion with 19.4…540 Mbit/s bit rate. It can be configured either as optical-to=electrical converter or as electrical-to-optical one. In SDI-TR-D15xx high sensitivity PIN diode is used as well as narrowband stabilized DWDM laser technology. Device allows transmit DVB-ASI, SMPTE signals and signals of all formats of standard definition. It provides optical refreshing, re-clocking and signal wavelength replacement. Sensitivity of SDI-TR-D15xx- not less than -30 dBm. By means of this device it is possible transmission of single 270 Mbit/s stream which may contain up to 16 channels formed by DWDM system.
Multirate optical MR-TR HD converter-transponder executes the same functions as SDI-TR but operates with signals up to 1.485 Mbit/s. MR-TR-D15xx.xx is really HD analog of SDI-TR-D15xx in terms of functionality and is similar to SDI-TR by parameters. For dividing optical signal Network Electronics Company manufactures the WOC-2 Series devices (Wideband Optical Coupler). These modules don’t require a power and provide full transparency in signal distribution. Optical energy of input signal divides between two optical outputs. Depending on dividing factor each connected to them cable is fed exact part of input signal. A module can work with both analog and digital signals.
There are three versions of WOC-2 with different input signal dividing factor:
Optical router is used for switching optical signal with no conversion to electrical one and back. Minimal loss at commutation and short switching time measured by milliseconds make this class of devices convenient for use within systems of automated protection switching. WDM (Wavelength Division Multiplexing) technology allows simultaneously create and transmit several signals over single Fiber Optic cable. Standard 2-channel WDM multiplexer lets transmit two independent signals over single fiber. Both duplex and simplex configurations of multiplexers exist. The systems able to perform multi channel WDM multiplexing are being built on a base of “4+1” architecture where “4” is a number of channels per frame and “1” is a port for upgrade allowing extend transmission capacity over Fiber Optic link. Multi channel WDM Flashlink systems can be of two types: with CWDM and DWDM multiplexing. CWDM systems designed for 4 or 8 wavelengths and DWDM systems provide multiplexing of up to 40 channels. For providing maximum level of interoperability the wavelengths for CWDM and DWDM are chosen in accordance with ITU-T G.694.1 (DWDM) and ITU-T G.694.2 (CWDM) standards. Since some CWDM wavelengths partially equal to DWDM wavelengths it becomes possible to create CWDM infrastructure based on DWDM technology.
The purpose of most systems given in table is clear with no notes that’s why below are the brief comments for some of them only.
WDM-C1xxx allows multiplexing/de-multiplexing the single mode cable light signal carrying up to 8 signals with various wavelengths. Device is passive and doesn’t require power and control. Erbium enriched EDFA-17 optical amplifier provides entirely optical amplification of large number of optical signals (1R regeneration) in C band which allows perform amplification of up to 40 WDWM channels simultaneously. Channels can differ from each other by signal format and transfer protocol. Device is built in 1RU frame with SC/PC connectors. Optical isolators provide simplex signal transmission over amplification path consisting of Erbium enriched optical fiber which prevents a device from falling into laser mode. GFF level equalizing filters guarantee uniform distribution of output power over all wavelengths signals. Optical output power is the sum of all signals that’s why a power per channel depends on number of channels transmitted over the cable. Single mode WDM-D15xx.xx module is similar to WDM-C1xxx but is used for DWDM multiplexing. 3R-2RU-DWDM device provides 3R regeneration of optical signals at their transmission on long distance. If fact this is a station operating as a repeater which performs optical-to-electrical-to-optical conversion for several signals. Signals formats supporting by systems depend on module’s version used for electric signal processing. Material provided by I.S.P.A. — Engineering Company |
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