Digital:
Sky digital via satellite, Ondigital (Now Freeview) via TV aerial, cable
digital
Analogue: Sky, Terrestrial TV aerial and cable.
The Truth
Prior to Digital entering the market all television broadcasts
were transmitted as an analogue signal, which meant a continuous
variable wave pattern being broadcast that was (and still is)
susceptible to interference. We have all seen the effects of
ghosted images or grainy pictures due to a poor signal. The
amount of space each channel uses on the waveband meant that it
was becoming near impossible to broadcast any further channels
without causing some interference with customers equipment or
existing TV channels.
Channel 5 who were awarded their terrestrial licence in October
1995 had a major task on their hands trying to fit this extra
channel into the existing waveband. They were aware that
broadcasting would be on a similar frequency to the output of a
large number of video recorders, hence the big channel 5 retune.
Then came the launch of Digital transmissions, Sky's satellite
digital service started in October 1998 followed shortly by
OnDigital in November 1998 and the more recent cable digital.
Digital broadcasting is transmitted in the form of binary
computer codes (IE 0100110) it can be compressed to give a
larger number of channels within a certain bandwidth and the
best part of all is that there are no grainy pictures. The
receiver either decodes the data to give a perfect picture or
where there is insufficient data there will be no picture at
all.
The result should be excellent picture quality with near CD type
sound.
The potential is enormous especially in the field of interactive
TV; we can now communicate with our TV set and retrieve
information due to the telephone line now being connected to the
digital receiver. We can now watch true widescreen TV pictures
(with a widescreen TV of course) and see those outside edges
which we have never seen before.
Looking to the future there is every possibility that we will be
able to watch any film that has ever been made or listen to any
song of our choice at the press of a button, even use the TV set
as a videophone link.
We can already communicate via email to anywhere in the world;
we can do our home banking, shopping and see what is on at the
local cinema.
Where will all this lead? Your guess is as good as mine.
The Myths
I have to change my TV set to a new digital one.
No! unless you have one of the very old 405 line TV's (which i
am sure must be extinct by now) virtually any TV is capable of
receiving Digital broadcasts via a set top box. We are seeing TV
sets being produced that have a built in Digital receiver and of
course widescreen TV's. If you are looking to buy a new TV you
can go for one of these features apart from that you old TV set
will work fine.
Tip
If you are buying a new TV with integrated Digital please
check with the retailer to ensure that you live in an area which
will receive the Digital broadcasts (Now called Freeview).
We have come across customers that have paid extra money for
this and have no chance of receiving it at all. To test your
area for digital terrestrial signals please use the following
link: Check
your Signal
Analogue signals are being switched off soon.
Not true, with the exception of Sky who announced they will be
switching off analogue satellite signals around the middle of
2001, the analogue terrestrial TV signals (TV aerial) will be
around for many years to come. |
