Fujitsu Siemens Computers Fujitsu-Siemens PC - Manual (Page 37)

11
Analog TV cards
With analog television, the picture and sound information to be
transmitted is prepared according to a modulation process and
forwarded on in wave form in a medium such as air or via a cable.
This requires an analog TV card with analog antenna input.
Digital TV cards
A digital TV card is required to receive digital programmes via the
PC. The signal is transmitted according to the standard for the
compression of TV signals, MPEG-2 (Motion Pictures Experts
Group, 2
nd
standard).
The digital technology packs the data as binary code in data
packets which are then decoded again by the receiver. This
decoding is carried out by the DVB card in the PC.
There are three options for receiving digital television
− DVB-C
(Digital Video Broadcast-Cable) reception via cable
− DVB-T (Digital Video Broadcast-Terrestrial) reception via
antenna
− DVB-S (Digital Video Broadcast-Satellite) reception via satellite
The reception quality is much better with DVB cards. As the digital
programmes are transmitted in MPEG-2 format, the TV programme
can also be processed directly on your PC hard disk.
A further difference is in the decoding of the MPEG stream.
Differentiation is made between TV cards with hardware MPEG
and TV cards with software MPEG.
• With hardware MPEG, the processing power is undertaken by
a chip on the TV card. This means that there is practically no
involvement of the PC’s CPU. The majority of the CPU’s
processing power remains available for other applications.
• With software MPEG, the CPU is responsible for the
processing power. Under some circumstances this may lead to
the CPU being noticeably overloaded.