50
Chapter 6 - TV Measuring Range
10713 Vxx.11
PE measurement (Packet Error)
6.2.2.4.10
Short interruptions in the DVB-T2 signal usually cannot be detected using MER and BER
measurement. They can make entire packets in the transport stream unusable for the MPEG
decoder, however. This can cause the picture to freeze temporarily or the sound to crackle.
The measuring receiver has a function with which corrupt transport stream packets are summed
from the point in time of entry of a new channel. This function runs in the background constantly.
An additional window can be shown on the display using the menu item
PE-INFO
. The number of
packet errors (PE = Packet Error) and the amount of time that has passed since the last tuning
process is displayed.
Picture and sound check
6.2.2.4.11
For digital television, picture and sound decoding take place in the MPEG decoder (see Chapter 12
Remote supply
6.2.2.4.12
The measuring receiver can provide a remote power supply via the RF input socket for an active
receiving antenna (see also chapter 9.9 Remote supply).
Constellation diagram
6.2.2.4.13
As soon as the measurement receiver is adjusted, the constellation diagram can be called up by
choosing the menu item
CONST
. Further information can be taken from Chapter 13 - Constellation
6.2.2.5
DTMB
DTMB (Digital Terrestrial Multimedia Broadcasting) is a Chinese standard for digital TV and radio
program transmission. DTMB was developed in 2007 out of the two drafts of DMB-T and ADTB-T.
DMB-T, developed at the University of Beijing, is a multiple carrier standard similar to the European
DVB-T/T2.
ADTB-T (single carrier) was derived from the American standard ATSC and was further developed
at the University of Shanghai. Parts of the specification of DTMB, which supports a single and a
multi-carrier mode, are written down in GB20600-2006. Like DVB-T2, DTMB uses for internal error
correction the LDPC mechanism (Low Density Parity Check) and for external error correction the
BCH mechanism (Bose Chaudhuri Hocguenghem). Thus the transmission standard is very robust,
which makes it suitable for mobile TV reception. Additional DTMB can also be used in single
frequency networks.
