These articles are to give a basic understanding of what these numbers mean and how they apply to practical use.
The first thing you will want to understand is the difference between Interlaced and Progressive. This is what the ‘p’ and ‘i’ stand for next to the numbers above. First, interlaced means ‘write one; skip one.’ This is how your 10 year old television puts a picture on the screen. To simplify, it will write one line across, then skip one line, write the next line, continuing in this fashion all the way to the bottom of the screen. Once the bottom of the screen has been reached, it proceeds back to the top to fill in the lines it missed.
Now to get a little technical, an interlaced television set, will do this process of going top to bottom 60 times a second. Seeing how it skips and writes; your set will produce a total of 30 complete refresh of a picture per second.
A progressive television, normally a digital television, will fill in every line as it proceeds down the screen. So instead of 30 refreshes per second, a progressive capable television will give 60 refreshes per second which results in a clearer and smoother picture.
So 1080p would be the best available signal right now, and your next step down would be 1080i/720p, then its 480p/i.
Now that p and i are understood, we can get into the numbers. A standard VHS tape can produce at best 180 lines of resolution. Standard DVDs can provide up to 480 lines of resolution. HD available through satellite (Bell/Star Choice/Dish Network/Rogers) provides a maximum signal of 1080i. Playstation 3 or Blu Ray are some of the few sources out there that provides an actual 1080p signal.
So HD is great, just keep in mind, purchasing a high def television will not automatically give you amazing picture quality like you see in the retail stores. You will need to give your television the signal, for example through a Blu-Ray player or a High Def Cable box. And most importantly you do need the right cables to connect your components. Yes the pushy salesperson is right.
But you do not necessarily need to purchase the 250 dollar cables, the quality difference between the cables you most likely will not notice. It is very important to connect using the right type of cables though. So to recap, you don’t need to spend a fortune on brand name cables, but you do need the right type of cables.