Structure of DTV Networks and Transmitting Stations - Digital Video and Audio Broadcasting Technology - page 527

31.2 Playout Center and Feed Networks
The Playout Center of the Bayerischer Rundfunk is located on the site of
the München-Freimann television studio. Here, 2 multiplexed data streams
are formed consisting of the ARD stream ("Das Erste, ..."), and the BR
stream ("Bayrisches Fernsehen“, "BR-Alpha“, ...). Throughout the country,
the ZDF stream comes directly from Mainz and contains (“ZDF, ...). The
other transport streams in the Playout Center directly at the Olympic
Tower in Munich are formed by T-Systems, partially by reception back via
DVB-S. These are 3 further transport streams containing private TV pro-
grams. These 3 transport streams are only broadcast in the DVB-T network
Southern Bavaria and not in Eastern Bavaria at the moment. The Olympic
Tower is linked to the BR Playout Center by fibre optic, the transport
streams of the Playout Center from T-Systems/Deutsche Telekom being
supplied to the broadcast studio via a few meters of cable. The ZDF trans-
port stream arrives from Mainz by optical fiber. All the transport streams
are then beamed up by microwave from the Olympic tower to the Mt.
Wendelstein by way of Schnaitsee-Hochries (T-Systems/Telekom) or via
Freimann-Wendelstein (BR). The MIP inserters for synchronizing the
transmitters in the single-frequency network are located at the output of the
respective Playout Center. The feed links and the components in the Play-
out Center are all provided redundantly. The transport streams are fed to
the DVB-T SFN Eastern Bavaria by microwave (ARD-MUX, BR-MUX)
or optical fibre (ZDF-MUX) via an ATM network.
31.3 Technical Configuration of the Transmitter Sites
In this section, the configuration of a DVB-T site will be explained by
means of three examples. These are the Olympic tower Munich
(T-Systems / Deutsche Telekom), Wendelstein (BR), and Brotjacklriegel
(BR) transmitters. As described in the previous chapter, the MPEG-2-
transport stream is supplied to the TS-ASI input interface over the most
varied networks, but finally via 75 Ohm coaxial cable. There is always a
spare link provided. The important factor is that, naturally, the same MIP
inserter always feeds the spare link. Each MIP inserter per se operates
completely asynchronously and only creates synchronous information in
the MPEG-2 transport stream by itself inserting MIP packets. Each MIP
inserter inserts these special transport stream packets virtually completely
freely into gaps in the MPEG-2 transport stream instead of null packets
(PID=0x1FFF).