Neutrik BNC connector Plug, straight 75 Ω NBLC 75 BSX 14 1 pc(s) NBLC75BSX14 Information Guide
Product codes
NBLC75BSX14
Document: NWP01, Version 1.0
3/8
1 Scope
Based on the increasing demands of high reso-
lution video formats, and high data rates coming
along with it, more and more interest is focused
on transmission lines (connectors, cables) and
their response to high frequency signals. Broad-
casters are facing the challenge of making their
studios, OB vans etc. future-proof with regards
to HD1080p and thus would like to ensure that
their equipment will provide reliable perform-
ance.
Return Loss and Jitter are identified to be the
key characteristics in judging compliance with
high resolution standards.
We, Neutrik AG, as one of the leading manufac-
turers of BNC connectors, decided to accomo-
date the evolution of HD formats and to test our
products with regards to the enhanced require-
ments. Theory on Return Loss and Timing Jitter
and corresponding measurement results are the
basis of this paper.
lution video formats, and high data rates coming
along with it, more and more interest is focused
on transmission lines (connectors, cables) and
their response to high frequency signals. Broad-
casters are facing the challenge of making their
studios, OB vans etc. future-proof with regards
to HD1080p and thus would like to ensure that
their equipment will provide reliable perform-
ance.
Return Loss and Jitter are identified to be the
key characteristics in judging compliance with
high resolution standards.
We, Neutrik AG, as one of the leading manufac-
turers of BNC connectors, decided to accomo-
date the evolution of HD formats and to test our
products with regards to the enhanced require-
ments. Theory on Return Loss and Timing Jitter
and corresponding measurement results are the
basis of this paper.
THEORY
2 HD Video Formats
At present the two common formats for HD video
in the professional broadcast and production
world are 720p/30 (a progressive format with
720 active lines progressively scanned at a rate
of 30 frames/sec) and 1080i/60 (an interlaced
format with 1080 active lines alternately scanned
at a rate of 60 fields/sec). Both formats are usu-
ally distributed over a high-definition serial digital
interface (HD-SDI) at a data rate of 1,5 Gbit/sec.
The next step in the search for the ultimate pic-
ture resolution is 1080p/60 which requires 3
Gbit/sec and thus twice the distribution data rate
of 720p/30 & 1080i/60. Following the earlier es-
tablished formats, 1080p/60* is distributed over
HD-SDI.
in the professional broadcast and production
world are 720p/30 (a progressive format with
720 active lines progressively scanned at a rate
of 30 frames/sec) and 1080i/60 (an interlaced
format with 1080 active lines alternately scanned
at a rate of 60 fields/sec). Both formats are usu-
ally distributed over a high-definition serial digital
interface (HD-SDI) at a data rate of 1,5 Gbit/sec.
The next step in the search for the ultimate pic-
ture resolution is 1080p/60 which requires 3
Gbit/sec and thus twice the distribution data rate
of 720p/30 & 1080i/60. Following the earlier es-
tablished formats, 1080p/60* is distributed over
HD-SDI.
* Please note that when this paper mentions 1080p/60, the
50-frame alternative 1080p/50, preferred in Europe, is also
included.
50-frame alternative 1080p/50, preferred in Europe, is also
included.
2.1 SDI
(Serial Digital Interface) - The
Ideal Transport Interface
SD and HD SDI have become the ubiquitous
interface standards within the professional
broadcast industry, and the success of the SDI is
broadly justified due to a number of specific
characteristics:
interface standards within the professional
broadcast industry, and the success of the SDI is
broadly justified due to a number of specific
characteristics:
•
Ability to transport uncompressed signals
•
Low latency
•
Cost-effective implementation
•
Robustness and reliability
•
Seamless interoperability
•
Reuse of existing infrastructure
Especially the opportunity to reuse the existing
infrastructure has been one of the critical suc-
cess factors for SDI and is characterized by the
ability of the interface to evolve over time, while
retaining the use of the existing cable installation,
patch panels, and BNC connectors.
The so far latest step of evolution for the serial
digital interface was the introduction of the
1080p/60 video image.
infrastructure has been one of the critical suc-
cess factors for SDI and is characterized by the
ability of the interface to evolve over time, while
retaining the use of the existing cable installation,
patch panels, and BNC connectors.
The so far latest step of evolution for the serial
digital interface was the introduction of the
1080p/60 video image.
2.2 1080p - Why a Higher Capacity Inter-
face Is Required
Among the obvious reason of higher resolution
and hence the opportunity to display video mate-
rial more realistic, 1080p provides an additional
major advantage:
1080i and 720p, the two original HD formats are
not ideally compatible. If deciding to go for one
format, it is quite possible that a customer will
request the material in the other format. Actually,
the conversion between 1080i and 720p, or vice
versa, is problematic, and may cause pixelization
and other undesirable artifacts.
By shooting in 1080p/60 respectively 1080p/50,
the higher frame rate HD image of 1080p/60 can
be easily converted into either 1080i or 720p with
no artifacts.
Thus, 1080p/60 provides the ability to offer a
product in 1080i or 720p formats with no loss of
image quality, and also introducing an extended
life of material, as it will still be available when
the 1080p distribution format emerges.
The drive to higher data rates and thus clock
frequencies (SMPTE standard
and hence the opportunity to display video mate-
rial more realistic, 1080p provides an additional
major advantage:
1080i and 720p, the two original HD formats are
not ideally compatible. If deciding to go for one
format, it is quite possible that a customer will
request the material in the other format. Actually,
the conversion between 1080i and 720p, or vice
versa, is problematic, and may cause pixelization
and other undesirable artifacts.
By shooting in 1080p/60 respectively 1080p/50,
the higher frame rate HD image of 1080p/60 can
be easily converted into either 1080i or 720p with
no artifacts.
Thus, 1080p/60 provides the ability to offer a
product in 1080i or 720p formats with no loss of
image quality, and also introducing an extended
life of material, as it will still be available when
the 1080p distribution format emerges.
The drive to higher data rates and thus clock
frequencies (SMPTE standard
1
specify that the
clock frequency will equal the signal bit rate**)
has focused increasing interest on Return Loss
and Timing Jitter.
has focused increasing interest on Return Loss
and Timing Jitter.
** The unit interval of a 270 Mb/sec SD-SDI signal equals
one period of a 270 MHz clock or 3.7 ns.
The unit interval of a 1.485 Gb/sec HD-SDI signal equals
673 ps or one period of a 1.485 GHz clock. Hence, the unit
of a 2.97 Gb/sec high frame rate HD-SDI signal equals
336.7 ps or one period of a 2.97 GHz clock.
673 ps or one period of a 1.485 GHz clock. Hence, the unit
of a 2.97 Gb/sec high frame rate HD-SDI signal equals
336.7 ps or one period of a 2.97 GHz clock.
3 Return
Loss
3.1 What Is Return Loss?
Return loss is signal attenuation caused by im-
pedance variations in the structure of a cable or
associated connectors. These variations cause
the signal to reflect (return) back to the source.
At lower frequencies, return loss is a minor ef-
fect; at frequencies above 50 MHz, it can have a
significant effect. At frequencies used for high-
definition video, 3000 MHz and higher, it is a
major, even critical factor.
pedance variations in the structure of a cable or
associated connectors. These variations cause
the signal to reflect (return) back to the source.
At lower frequencies, return loss is a minor ef-
fect; at frequencies above 50 MHz, it can have a
significant effect. At frequencies used for high-
definition video, 3000 MHz and higher, it is a
major, even critical factor.
3.2 About Return Loss
With the introduction of HD signals coming along
with higher data rates and thus increased clock
with higher data rates and thus increased clock