Pagina 40 - TELE-satellite - La Più Grande Rivista del Mondo Sul Commercio TV Digitale

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TELE-satellite International — The World‘s Largest Digital TV Trade Magazine
— 09-10/2012
1. Main menu of the DS2400T with twelve
different measurement modes.
2. Level measurement: Results are dis-
played as numerical values and as a bar
chart. Seen here is an analog transponder
with simultaneous measurement of video
and audio levels. The level is below a pre-
defined threshold, hence the FAIL indica-
tion of the automatic quality check.
3. Signal strength measurement of a
DVB-C transponder. Here too, the result is
displayed as a numerical value and a bar
chart. In addition, the meter shows MER,
PRE-BER and POST-BER parameters. The
automatic quality check gives the PASS
4. The constellation diagram is greatly
helped by the high-resolution TFT display.
5. Long-term BER measurement: As the
signal in our test center is too good, the
antenna cable was plugged off for a split
second. The meter reacted swiftly and
reliably. Long-term measurements are
great for detecting occasional faults at a
client’s system and for establishing a cor-
relation with other events.
6. MER vs. carriers: This type of measure-
ment is still not very common and shows
the MER (Modulation Error Rate) of each
carrier on a DVB-T transponder. This way
it is possible to determine interference on
individual carriers which results in occasio-
nal loss of video, even though the average
MER looks fine. No other measurement is
capable of identifying such problems.
7. The marker was moved to carrier no. 2155
in order to find out its specific MER. The
DS2400T also offers a peak hold mode for
such cases.
8. ECHO measurements are particularly
important with SFN (Single Frequency
Network) DVB-T networks, since a second
time-delayed signal on the same frequency
can easily cause reception problems. At
our location, however, no echoes can be
received even though we use a SFN.
9. The DS2400T is able to generate a very
detailed spectrum. Seen here is the entire
spectrum, with two markers available for
measuring the signal level at two different
positions and showing the difference bet-
ween the two.
10. Speed is not the main point of this
meter’s spectrum, but this is not an issue
for DVB-T, DVB-C and CATV – contrary to
DVB-S. Small frequency spans offer much
more help, as they can visualise even indi-
vidual carriers (and their problems) of the
within the expected range and the rub-
ber protection all around the DS2400T
safeguards against damage when used
outside and up on the roof.
While the HF input is placed on the back
panel of the device, USB input and power
supply socket are located on the front
panel. In addition, the front panel fea-
tures a high-resolution TFT display and a
total of 17 buttons below the screen. An
LED indicates the current status of the
battery pack.
All buttons are self-explanatory and
provide a pleasant pressure point with
just the right amount of feedback you
need. The first row of buttons consists
of the F1, F2 and F3 function keys whose
currently active function is shown on
the bottom line of the display. In the
second row there is the HOME button
that always brings you back to the main
menu in an instant, as well as the UP and
DOWN buttons for navigating between
menu items. Below this row comes the
numeric pad that is set up just like on
phones, which means that each number
can also be used to type three different
letters (much like texting), so that you
can easily enter names as well, for ex-
ample. The last row of buttons features