Monday, 6 February 2012

Analogue versus digital


The new world of digital television can be fraught with many problems,which at times make you long for the good old days of analogue with its ghosting or shadowing as many people call it.
Analogue was always very forgiving depending very much on your point of view of what makes a watchable TV picture.
Analogue pictures were always very forgiving ,they could be grainy caused by low signal level and still be totally watchable,or suffer from interference scattering across the picture due a local traffic,or local TV transmitters,what constituted a good signal was purely a matter of opinion

Digital totally changes the state of the playing field.
Digital signals are composed of information which if it cant be read it causes the picture to freeze or break up intermittently,as the TV set or freeview struggles to cope with lack of information.
This error correction technology as long been in use in your CD player,to correct errors caused by dust or finger marks.
Try playing a dirty CD and see how the player copes with it mostly by jumping or skipping parts of the track.
Exactly the same happens in the visual for a TV picture.
A digital TV signal is measured not just by level but also by quality,a good high level can have a very low quality causing the picture to break up,low quality is literally a voltage generated by for instance corrosion on a connection.

One of the biggest causes of this can be poor quality co ax cable,which did a fine job for analogue but is a total disaster for the digital,age and the weather takes a heavy toll on the TV aerial.
Digital co ax now as to be of a minimum quality to avoid these drop outs or at least reduce them to the point where they aren’t intrusive,another of the causes for a low quality signal is corroded connection on the aerial itself,or water entering down the cable,or even a poorly fitted co ax plug or a co ax cable being to close to a mains lead.
Some of the newest TV’s such as Panasonic also have a built in meter for measuring bit error rate or the amount of bits or digital data that as been introduced,ideally this should be zero,but that can difficult to attain,around 1 or 2 is the best


If you have a distribution amplifier either behind your TV set or buried in your roof this could well be an older unit that isn’t up to the job of carrying delicate digital signals,anymore than 4 years old then you can point the finger of blame at this,or the masthead amplifier you have either in your loft or on your TV aerial mast,have a quick glance at your aerial to see if it as a box with wires protruding out of it.
Trees can also disrupt the signal,literally depending on what species they are or the size of the leafs themselves,so if during windy weather the picture breaks up more often have a look to see if your aerial is pointing through trees,obviously more so during the summer,an higher mast is the way around this.

Take the time to dig out your TV s signal meter system to give you a better idea of what exactly your signal state is this is usually found under menu set up, and then manual tuning,look for the signal display,then signal quality.






Atlas aerial systems
Supply and install of TV aerials and satellite systems TEL:07891903013
125,East Bawtry Road
south Yorkshire
S60 4LQ