Components; Satellite Front End; Functional Distribution; Tuner - Loewe Q2500B Serviceanleitung

Technology of Q 2500 colour TV set

3.4 Components

3.4.1 Satellite front end

3.4.2

Functional distribution

The satellite front-end processes the signal of
the 1. satellite IF coming from the Universal-
LNC or Multiswitch up to the MPEG-2 carrier
current, fed to
plexer/decoder. It also houses the compo-
nents for the supply and control of the an-
tenna units. The functions mentioned are dis-
tributed to blocks of the Sat 6 (Tuner, LNC
supply) unit DVB decoder (AD conversion,
demodulation, forward error correction). The
separation is implemented via an ana-
logue/digital satellite tuner in order to be able
to use redundancy free processing of TV and
DVB signals. The reasons for the choice of
interfaces are:
Document Q 2500
the MPEG-2 demulti-
Fewer requirements for the screening of the
Sat 6 unit and
analogue baseband interface to DVB decoder.
Due to the functional unity, the relevant pa-
rameters for DVB reception of the Sat 6 unit
are specified in the following.
3.4.3

Tuner

The tuner converts the signal of the 1. satellite
IF in the base band. Signal processing for
analogue and DVB signals is distinguished
only in respect of demodulation, and is there-
fore almost identical with respect to the pre-
filtering and amplification stages, mixing on
the 2. IF, channel selection and amplification.
For this the implementation of an ana-
logue/digital combi-tuner is advised.
The Sat 6
BS2W7VG2002 (Sharp) analogue/digital sat-
ellite tuner
54
low-interference
unit incorporates
© Loewe ProCollege
quasi-
the