Basic HTML Version
49
www.TELE-satellite.com —
09-10/2012 —
TELE-satellite International —
全球发行量最大的数字电视杂志
a meaningful result you first have to se-
lect whether your power supply runs with
50Hz or 60Hz.
Threshold measurement
You’ve read it before, but once again
the DS2400T comes with a power-
ful measurement option that does not
have many peers. Installers often have
to obtain a quick overview of all chan-
nels distributed in a cable network. For
analog channels, Deviser has imple-
mented a neat routine that automatically
measures all available channels and then
provides detailed information on chan-
nels with video or audio levels below a
set threshold. The process resembles
the bar search, and here too the results
are shown with a bar graph. When the
measurement is completed the final re-
sults are shown on the display, complete
with minimum and maximum signal lev-
els and signal ratio.
Carrier/noise ratio
Frequently called C/N measurement,
this function determines the ratio be-
tween carrier and noise, or in other
words: the signal level in relation to
background noise. Sufficient separation
of the two is paramount for flawless vid-
eo. Obviously this measurement applies
to analog signals only, but Deviser once
again demonstrates attention to detail
since you can only select analog chan-
nels of the channel list for this measure-
ment in the first place.
Return channel
The last measurement option should
be selected to evaluate the return chan-
nel in cable networks. The 5MHz to
45MHz or 5MHz to 65MHz spectrums are
active for this type of measurement.
Configuration options
No installation job is the same as the
one before, so luckily this meter offers
a range of customisation options in the
system configuration menu:
Information about the DS2400T
Here you cannot only access soft-
ware and hardware version numbers,
but also the calibration date. This piece
of information is particularly important
for contract jobs performed by certified
installation companies, which have to be
able to prove calibration of their devices
on request. This goes to show yet again
that Deviser has designed a meter that
targets the professional market in a con-
vincing way.
Generic configuration settings
Use this menu item to define a time
limit for automatic switch-off, for exam-
ple, which can help save valuable battery
capacity. Plus it is possible to adjust ad-
ditional important parameters such as
OSD language, among other things. The
meter we received for our test offered
English, Dutch, Turkish and Chinese. If
you need to find out the status of the in-
ternal memory you can also look it up
here.
Configuration of measurements
By default, signal level and strength
are measured in dbµV, but you can also
change that to dBmV or dBm, which does
make sense when evaluating digital sig-
nals, since dBµV is only used for better
comparison with analog signals in digital
modulations. The DS2400T from Devis-
er comes fully calibrated, yet installers
have the option of manually calibrating
the meter for individual measurements.
This way it is possible to calibrate several
meters of the same installer in a way that
makes sure all devices show exactly the
same signal level of a reference signal.
Alternatively, it is of course also possible
to calibrate the DS2400T against a refer-
ence meter, if one is available. We believe
this is an impressive feature that will be
appreciated by many professionals.
Using the LIMIT SETUP menu item it
is possible to define minimum and maxi-
mum values for measurements, as well
as a threshold level for the automatic
quality check. All these parameters can
be set individually for DVB-T, analog TV
and DVB-C. What’s more, the DS2400T
comes with an integrated auto diagnose
mode which is run every time the meter
is turned on.
The VOL & TEMP menu item hides an-
other interesting feature: Use it to meas-
ure the voltage of the signal arriving at
the HF input. This way it is possible to
check the power supply for all active
components in a cable installation, or to
find out if undesired voltage exists due
to faulty connection boxes or bad insula-
tion. The same screen mode can be used
to call up the current voltage of the inter-
nal power pack. We were surprised that
– in addition to all options mentioned
above – it is even possible to find out
the meter’s internal temperature. In our
opinion this is not only quite unusual, but
also very useful.
Channel lists
Deviser ships its DS2400T signal me-
ter with a number of pre-stored channel
lists which can be edited directly on the
meter or – more conveniently – on the
PC using the supplied Toolbox software.
In each individual channel list it is pos-
sible to activate analog channels only,
digital channels only, or both types. This
means there is no need for installers to
set up different channel lists for differ-
ent broadcasting types. It goes without
saying that the DS2400T sports an au-
tomatic channel search which can be de-
fined with parameters such as analog/
digital or all channels. Digital channels
are displayed complete with DVB norm,
bandwidth, modulation and symbol rate.
In our test the meter turned out to be
a quick performer, and it also found all
channels carried in our cable network.
The search result is presented in an
easy-to-use chart. In addition, there is
an integrated file manager which can be
used to call up stored measurements or
to delete files that are no longer required
in order to free up memory.
Factory reset
Not that we like to find ourselves in
such a situation, but if worse comes to
worst you can always reset all param-
eters to their default values. This option
is available in most signal meters tested
by us, and is indeed a must-have feature.
File manager
The DS2400T comes with a USB adapt-
er cable and a CD ROM, on which you
can find a PDF file with a very detailed
user manual. Even though it is only avail-
able in English it is perfectly written and
therefore an enormous help for discover-
ing all nooks and crannies of this meter.
The main reason for me to install the
software was so that I was able to ad-
just the channel list to the offering of
my cable provider. And this was actually
the first time I encountered problems in
connection with the DS2400T. My test
computer was running a 32bit version
of Windows7 for compatibility reasons,
the second CD Rom entitled DRIVERS
that is shipped with the device however
only includes a software version for 64bit
versions of the Windows7 operating soft-
ware, which meant that the DS2400T
was not detected automatically. After
looking at all my options I finally decided
to install the existing drivers in the 64bit
directory and give the whole installation
another go. Miraculously, this worked on
my 32bit operating software.
I tried the setup on a second PC with
the 64bit version of Windows7 and – as
expected – the driver was installed with-
out any hassle whatsoever. However,
I was faced with another problem: The
driver that comes with the DS2400T in-
stalls a COM interface, which means the
meter is connected to the PC through a
virtual RS-232 interface. In theory, this
is a worthwhile strategy, but these days
PCs and laptops support Bluetooth and
other communication devices so that
COM ports 1 to 10 are frequently used
for those devices and are not avail-
able for the meter. While you can select
the COM port of the DS2400T with the