In Broadcast - CABSAT 2015 - 24

24

www.inbroadcast.com | CABSAT InShow Guide | 10-12 March 2015

MT2000: The Swiss Army
Knife of Television Broadcast
Engineers
Linear Acoustic has created the answer to all the problems
with end-to-end digital audio testing in broadcast chains...

F

or years, end-to-end system
testing of digital audio in broadcast
chains involved large, clunky, pieces
of equipment. Bring multichannel
and coded audio into the picture, and
this became even more complicated.
Devices such as the Dolby DM100
made this a bit simpler, but are now
obsolete. The Linear Acoustic MT2000
Multichannel Bitstream Analyzer fills
this void, meeting the need for an
updated device, capable of analysing
audio in multiple formats, carried via
multiple interfaces.
"We saw a need in the marketplace
for a modern bitstream analyser and
test generator that is very portable
and powerful." says Larry Schindel,
Director of Technology for Linear
Acoustic. "Knowing firsthand the types
of problems a broadcast engineer
typically encounters certainly served
as inspiration for what features to
include."
The MT2000 analyses audio streams
containing PCM, Dolby Digital Plus,

With its vast number
of applications, the MT2000 is
the ultimate multi-function tool

Dolby Digital, and Dolby E, and
can optionally decode those Dolby
formats. Some of the stream analytics
supported by the MT2000 include the
ability to measure and quantify errors
in the bitstream, at both the AES-3
and coded audio (SMPTE 337M) layers.
Items such as sample rate, word length
(bit depth), clock accuracy, CRC errors,
Pa alignment, and PCM/non-PCM
stream identification, are supported
at the AES-3 layer. When dealing
with non-PCM streams, the MT2000
displays essential SMPTE header
information, including Pa type, Pa
spacing, along with Pc and Pd values.
When the input audio is a Dolby
format, such as Dolby E, the MT2000
is capable of measuring the line
position of the Dolby E frame, in order
to ensure that it will not be corrupted
during a video switch. When the audio
is Dolby Digital, full metadata of the
AC-3 stream is displayed. If the input is
Dolby Digital Plus, advanced features
such as 7.1 or Main + AD signals can be
quantified.
Perceptual loudness measurements,
according to the ITU BS.1770
recommendation (-1, -2, and -3),
are supported, and enhance the
feature set even further. Dolby
Dialogue Intelligence, which is an
advanced speech detection algorithm,
is available during the loudness
measurements. This allows loudness
measurements based on the portions
of the input signal that contain the
characteristics of dialogue, and
provides measurement results in
a value that more closely matches
human perception of the average
loudness. This is very useful for
estimating the loudness of long-form
programmes, especially programmes
with wide dynamic range. Two
different loudness calculations (of
the same programmes) are displayed.
This is useful as, for example, it allows
monitoring of the integrated loudness
of an entire programme and a shorter
term, say 10 second, loudness of
programme segments.

The usefulness of the MT2000 is above and beyond that
of an average audio analysis tool

The MT2000 also generates test
signals and can output them as PCM
or in Dolby coded formats, and is
capable of analysing input streams,
while outputting test signals. Larry
points out this leads to being able to
perform some advanced testing, such
as system latency measurements, "It
generates a special signal and outputs
it into the system the engineer wants
to check. When they bring the system
output back into the MT2000, it tells
them how long the signal takes to get
through their system." This type of
testing facilitates the ability to ensure
audio and video are synchronised
through the plant. The MT2000 can
also generate an A/V Sync test signal
that the engineer can then inject into
their system, to visually check their
timing calculations and settings for
A/V sync.
The inputs and outputs support
modern professional broadcast and
consumer interfaces, including AES-3,
SDI (HD or SD), TOSLINK optical, and
optionally MADI, DVB-ASI transport
streams, and even HDMI input. This
wide array of audio sources - notably
SDI, which carries uncompressed video
with 16 channels of audio for picture
and sound in one connection, and
HDMI, the interface of choice on the
consumer side - makes the MT2000
quite the versatile tool.
"It's a very flexible product." notes
Larry. "It's not designed to sit in any
one place in the broadcast chain. It's
meant to be used by engineers walking
around, to analyse and troubleshoot
audio streams, at all different points in
the broadcast chain."

The MT2000 can also verify that
audio is embedded into the proper
channels and is properly encoded. All
16 channels of audio in SDI streams
are available for de-embedding,
embedding, or re-embedding. Pairshuffling from the SDI input to the
SDI output is supported, along with
embedding signals from the test signal
generator and/or audio from other
sources, such as the AES or TOSLINK
input.
For any purpose you use it for,
you can listen either via the built-in
speaker, or plug in your headphones
to listen more closely - a huge plus
in the sometimes noisy environment
of a television production facility or
machine room.
Clearly, the usefulness of the
MT2000 is above and beyond that
of an average audio analysis tool.
"It's meant to be carried around the
facility." Larry adds. "This should
be in everybody's toolbox. Remote
trucks should have one, production
studios should have one, engineering
departments should have one. This
is an essential piece of audio test and
measurement equipment, brought
to you by passionate audio experts.
It's as useful to an audio engineer or
technician, as a multimeter is to an
electrician."
With its wealth of applications, the
MT2000 really is the ultimate multifunction tool for today's broadcast
engineer.
To learn more about Linear
Acoustic and its products, visit
www.TelosAlliance.com/Linear
http://www.inbroadcast.com http://www.telosalliance.com/Linear/MT2000 http://www.TelosAlliance.com/Linear
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