TM
USING Pure Digital Fiberlink®
SDI FOR DISTRIBUTING SIGNALS
WITHIN A BROADCAST FACILITY
MARKET: Broadcast Video
DOC. NUMBER: T-17
The advantages of fiber optic transmission include
error-free transmission, immunity to interference and
no degradation of the signal. CSI’s fiber optic trans-
mission system uses high-speed pulse modulation
techniques to transmit and receive the digital video
pulse stream without any alteration or interpretation
of the original signal. Along with the serial digital video,
This TECHnique illustrates how the Pure Digital
imbedded audio and EDH control signals are also
Fiberlink SDI transmission system, manufactured
transmitted.
CSI’s fiber optic transmitter provides an equalized
by Communications Specialties, facilitates distribu-
tion of Serial Digital Video (SDI) in a broadcast video
cable input with a loop-through output for monitoring
of the transmitted signal. Two re-clocked outputs at
environment.
the receiver eliminate any jitter and drive the signal
up to an additional 300 m of coax cable. The system
Problem:
Even under ideal conditions, the highest cleanly passes pathological test signals up to and
quality coax cable is only able to transmit an SDI including 360Mb/sec.
signal a maximum of 300 meters. Standard RG-59
The SDI transmission system is available for use
coax cable is even more limited in its performance with multimode or single-mode fiber. The multimode
and is quite susceptible to electrical and environ- system is suitable for transmission over distances
mental interference.
Serial Digital Video (SMPTE 259, CCIR 601) sig-
nals are being used with increasing frequency within
broadcast facilities as this format maintains signal
quality through multiple video processors and mul-
tiple generations of recording. For broadcasters, the
transition to serial digital (SDI) involves not only an
investment in new, digitally-based equipment, but also
requires an evaluation of the distribution system nec-
essary to route the wider bandwidth, fast-speed digi-
tal signals throughout the facility. Until now, most sta-
tions have relied on coax distribution systems to sup-
port the traditional analog composite (CVBS) and
analog component (YUV or Y/R-Y/B-Y) signals in use.
However, it is quickly becoming apparent that these
installed, coax systems are limited in their ability to
support the more demanding SDI standards.
Solution:
Fiber optic transmission is an ideal means
for distributing serial digital video signals throughout
a broadcast facility. CSI manufactures the Pure Digital
Fiberlink transmission system for SDI, designed
specifically to support all SMPTE 259M, 294M and
305M signals at data rates of 143, 177, 270 and
360Mb/sec. This point-to-point transmission system
may be used to send SDI signals from room to room,
floor to floor, building to building, studio to transmit-
ter (STL) and even over long distances up to 60 km.
Point-to Point SDI Fiber Optic Transmission System
Fiberlink and TECHniques are trademarks of Communications Specialties, Inc.
© 2000, Communications Specialties, Inc.
  Communications Specialties Application Note
Page 2:
USING Pure Digital Fiberlink SDI FOR DISTRIBUTING
SIGNALS WITHIN A BROADCAST FACILITY
up to 2 km. The single-mode system, which is la-
ser-driven, may be used for all applications requir-
ing support for up to 60 km.
Using SDI Links with Matrix Routers:
SDI fiber
links can be assigned to several inputs and outputs
on SDI matrix routers, thus enabling multi-point as
well as mid to long range distribution of SDI signals
over fiber.
Selecting Multimode or Single-Mode Versions:
If the SDI Link will be used with fiber that is already in
place, then it is important to establish whether the
fiber is multimode (50 or 62.5 microns) or single-
mode (8 or 10 micron). This will determine which
version transmitter/receiver pair to specify. If you are
specifying a new system, then it is necessary to
calculate the loss budget of the system (distance,
patches, splices, adapters and type of fiber) in order
to determine if multimode or single-mode fiber is ap-
propriate. (See “Introduction to Fiber Optics” to de-
termine the loss budget.)
ST, SMA or FCPC Connectors:
CSI recommends
the use of ST connectors with multimode fiber. If
existing fiber is terminated in an SMA connector, then
the 6300 ST to SMA adapter may be used. For use
with single-mode fiber, CSI recommends use of
FCPC connectors. If existing fiber is terminated in
an ST connector, the 6310 FCPC to ST adapter may
be used.
•
SDI Transmitter
Multimode 1310 nm, ST connector ........3120-3
•
SDI Receiver
Multimode 1310 nm, ST connector ........3121-3
•
SDI Transmitter
Single-mode 1310 nm, FCPC conn. ......3120-7
•
SDI Receiver
Single-mode 1310 nm, FCPC conn. ......3121-7
•
ST Male to SMA Female adapter
multimode ................................................. 6300
•
ST Male to FCPC Female adapter
Single-mode .............................................. 6310
•
Educational Guide:
An Introduction to Fiber
Optics
•
Educational Guide:
An Introduction to Fiber
Optic Cable and Connectors
•
T-21 Calculation Transmission Distance of
Fiber Optic Equipment
Fiberlink is a registered trademark and TECHniques is a trademark of Communications Specialties, Inc.
© 2000, Communications Specialties, Inc.