TELE-audiovision - The World’s Largest Digital TV Trade Magazine - page 37

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09-10/2013 —
TELE-audiovision International —
全球发行量最大的数字电视杂志
29. The fifth screen contains a
PCR measurement. PCR stands
for Program Clock Reference
and serves to determine the
transit time delay between the
received signal and the receiver
clock (27 MHz). A PCR is perio-
dically added to the transport
stream. The Deviser S7000 reads
this PCR and shows how pre-
cisely synchronized the internal
27 MHz clock is with the PCR
signal. The difference should
normally be no more than +/-
500ns. Since the PCR bytes
themselves are generated with a
27 MHz clock and embedded in
the transport stream, the resolu-
tion is limited to 37ns. The accu-
racy shown in the upper graphic
highlights the timing error within
the multiplexer, but not any run-
time delays that were generated
within the network. As you can
see, a perfectly synchronized
transport stream is being recei-
ved indicating that no errors
existed in the clocks of various
multiplexers and modulators
at the headend. If the delays
are longer than 500ns, then the
receiver could have problems.
In the lower graphic the timing
offset between the PCR bytes
is shown. Run-time delays that
were generated within the net-
work can be derived. And here
too everything is in the green.
Even though small delays are
visible, they don‘t yet have any
influence on the reception qua-
lity. It is therefore an extremely
important measurement when it
comes to maintaining head sta-
tions and broadcasting systems
.
30. The PROG LIST shows the
provider‘s channels. This infor-
mation, as long as it‘s correctly
entered into the NIT by the pro-
vider, makes possible a faster
channel scan for receivers since
known transponders do not have
to be scanned separately. Unfor-
tunately, many broadcasters
don‘t stick with the standards
and all too often don‘t include
the correct NIT information in
the stream. Thus a transponder
would show the wrong satellite
name or even no name at all.
And then there‘s the case where
the name of the satellite, bou-
quet, etc., is spelled wrong or
non-uniform upper/lower case
lettering is used. Here the res-
ponsible technician should defi-
nitely have an S7000 placed in
his hands!
31, 32, 33, 34. The seventh menu
screen PSI/SI lets you navigate
within the complete TS table.
All data can easily be analyzed,
PAT, PMT, CAT, NIT, SDT, TDT
and MIP. The arrow buttons let
you navigate within the indivi-
dual branches of the table giving
you information on the smallest
detail. It‘s an indispensable aid
when working with multiplexers
and you want to make sure that
all the parameters are correctly
configured.
35, 36. The transport stream
analyzer‘s eighth menu screen
is a highlight of the S7000: here
individual transport stream
packets can be stored and dis-
played. After recording, these
data packets can be displayed
byte-by-byte.
37. In the last menu screen the
transport stream‘s reception
parameters can be read and
edited. This permits the simula-
tion of different situations; the
S7000 can be configured like
similar receivers. There is no
other known signal analyzer that
can do this.
38, 39. If you insert a USB sto-
rage device into the S7000, the
transport stream can be recor-
ded if it is in transport stream
analysis mode. The streams
are recorded in *.ts format, a
format compatible with many
PC processing programs such
as TS Reader, VLC or TransEdit.
Of course, recorded transport
streams can be played back on
the S7000. In this case all of the
listed analysis tools are availa-
ble. In other words, you can
record a transport stream on a
receiver or computer and then
analyze it with the S7000.
40. The currently displayed
image on the screen can be
saved in JPG format to the
analyzer‘s internal memory by
pressing the Store button. If you
happen to be in one of the vari-
ous measurements modes, the
analyzer will ask you if want to
save the current screen or the
displayed data. If the latter is
chosen, the data can be recalled
offline on a PC and if desired
can be displayed and edited,
for example, with the marker.
Using the analyzer‘s File Mana-
ger (accessible from the Main
menu), the data stored in the
analyzer can be displayed, dele-
ted, edited or saved to a USB sto-
rage device.
41. The active transponder
can be edited and stored in a
special channel configuration
screen. In this way the channel
list can also be managed and
updated directly on the S7000.
This process is actually quite
comfortable so that you don‘t
necessarily need to refer to the
Settings Editor on the included
CD.
42. Back in the Configuration
menu the TS INTERFACE makes
it possible to activate or deacti-
vate the ASI input. This interface
lets you stream transponders
to other devices or take the ASI
streams from other devices and
scrutinize them with the S7000‘s
transport stream analyzer.
43. The Configuration menu
is divided into five sections:
ABOUT, GENERAL, MEASURE,
CHANNEL and INTF. In the first
section a variety of analyzer
information is displayed, for
example, the version number
and the different modules.
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