W6155A Datasheet, PDF (4/16 Pages) Keysight Technologies – X-Series Measurement Application

04 | Keysight | ISDB-T/Tmm X-Series Measurement Application N6155A & W6155A - Technical Overview
ISDB-T, ISDB-T_SB , and ISDB-Tmm Standards Overview
ISDB-T, ISDB-T_SB and ISDB-T_B
Integrated services digital broadcasting
(ISDB) is a Japanese standard for digital
television (DTV) and digital radio used by
the country's radio and television stations.
ISDB-T and ISDB-T_SB standards are the
digital terrestrial broadcasting systems
developed by Japan’s Association of Radio
Industries and Business (ARIB). ISDB-T,
as a terrestrial broadcasting system, has
also been adopted by Brazil, where it is
called ISDB-T_B. ISDB-T and ISDB-T_B both
use an identical physical layer. ISDB-T_SB is
used for audio and data program trans-
missions. The system and specifications of
ISDB-T_SB are similar to ISDB-T, except that
the bandwidth is narrower and there are
only one or three segments in the channel.
Keysight’s ISDB-T measurement applica-
tion supports measurement on both ISDB-
T and ISDB-T_SB standards.
ISDB-Tmm and AC
Segment and layer in ISDB-T
The new VHF band, 207.5 to 222 MHz,
introduced in 2011, after the analog TV
switch-off in Japan. The government
announced that ISDB-Tmm (Terrestrial
Mobile Multimedia) will be used for new
multimedia service in this band. The ISDB-
Tmm standard employs the concatenated
transmission method which, combining
blocks of the 13-segment (Type A) and the
1-segment (Type B), eliminates the need
for a guard band, making it possible to
apply it to various bandwidths. Figure 2 is
an example of ISDB-Tmm frame structure
consisting of two Type A super segments
and one Type B super segment.
ISDB-T supports hierarchical transmis-
sion by introducing hierarchical layers,
which means different services such as
HDTV, multi-channel SDTV, and data, can
be transmitted in one frequency channel.
There are 13 OFDM segments in the ISDB-
T transmission channel. Each layer consists
of one or more segments which have their
own transmission parameters (such as the
inner coding rate, modulation scheme, and
time interleaving length). A maximum of
three layers can be provided, defined as
Layer A, B, and C.
Partial reception
Auxiliary channel (AC) is used to convey
additional information on modulation
signal-transmission control, or earthquake
alarm information. The earthquake infor-
mation is transmitted using the AC of the
center segment (segment No. 0).
ISDB-T also supports partial receptions.
Partial reception refers to the segment
at the center of the transmission system.
The range of frequency interleaving can be
limited within the segment, so that narrow
band (1-seg) receiver can receive services
contained in the center segment. The gen-
eral concept of hierarchical transmission
and partial reception is shown in Figure 1.
Figure 1. Hierarchical transmission and partial reception in ISDB-T