You may quite possibly have seen the specifications in your local electrical retailer, with LCD and Plasma TV sets carrying the “HD Ready” logo. But what does this actually mean?

The TV’s screen must support 720p and 1080i screen modes. The TV must also support HDCP compliance. The native resolution supported must be equal or greater than 1,366x768 pixels. This means that 1080i signals will be downscaled to fit on the screen as they are larger than a 1,366x768 screen will allow.

A newer standard has already been released called “Full HD”. Full HD must be able to support 1080p. 1080p requires a minimum resolution of 1,920x1,080 pixels. So for the moment these displays tend to cost a bit more than a standard HD Ready TV.

What is the difference between an interlaced (i) and progressive (p) screen mode?

Regardless of the resolution, the picture you see on your TV screen is made up of picture frames displayed sequentially. Each frame contains a number of horizontal picture lines that make up that single frame.

Interlaced
For the old analogue PAL TV system (used in Europe) which uses 576i (interlaced). Each picture field contains 288 horizontal lines of picture data. Why 288? The term “interlaced” means that in order to see one complete frame of picture data, each frame takes two scans to perform. In the first half frame, each “odd numbered” horizontal lines are displayed (field 1), and in the second scan, each “even numbered” horizontal lines are displayed (field 2). The PAL system allows 25 picture frames to be displayed per second. (exactly half of the 50 frames per second available).

So let’s see what that actually means when High Definition interlaced picture screen modes are used.

720i contains 360 horizontal lines of picture data per field (2 fields = 1 frame).
1080i contains 540 horizontal lines of picture data per field (2 fields = 1 frame).

Progressive
Progressive is much easier to understand. Each picture frame contains all the available horizontal lines of picture data. There is no need to break the frame of picture data into odd and even horizontal lines and display them as two half frames. This also means the complete picture frame rate is now 50 frames per second, which results in a more detailed, flicker free picture on your TV screen

Now let’s see what that means when High Definition progressive screen modes are used.

720p contains 720 horizontal lines of picture data per frame
1080p contains 1080 horizontal lines of picture data per frame

So what does all this add up to?
The human eye is most sensitive to horizontal lines of picture data. In other words, the more horizontal lines of picture data that can be displayed, the more detailed and smooth the picture will be. A 1080p frame of picture data will contain around four times the detail of an old analogue PAL TV screen.

So those are the facts and figures.
Which display modes are supported by your HD TV?
How does your HD TV perform with HD content?
Would you consider upgrading to "full HD"?
Will you just buy "full HD" to start with?
Let's hear your views.