Explain the terms - Resolution,contrast ratio and Fast response time in a LCD T.V?

Answer 1

Resolution is the number of pixels or "scan lines" on a screen.

HDTV starts at 1280 x 720p and goes up to 1920 x 1080p. What these numbers mean are as follows:

The first number is the horizontal resolution or the number of individual pixels drawn from the left side of the screen to the right. The second number is the vertical resolution, or the number of pixels or scan lines drawn from the top to the bottom of the screen. Generally, the higher the native resolution of a set, the sharper the picture.

You may occasionally notice that a set will be just referred to by the second number. This tells you what HDTV standard is adheres to or can accept. When people say they have a 1080p LCD this means that it has at least a 1920 x 1080 native resolution. When they say they have a 720p HDTV, this means that it has at least a 1280 x 720 resolution.

After these numbers you will usually see a "i" or a "p". This refers to the way the picture is drawn on the screen. A HDTV with a 'p' or "progressive scan" set draws all the lines of resolution at once. A HDTV with a 'i' or "interlaced" draws every other line in alternating sequence to form the entire picture. The progressive sets are generally more desirable. However, most mainstream sets generally accept 720p or 1080i signals and they look very similar in quality. 1080p is starting to become more mainstream but currently no television stations broadcast in 1080p so it is not a critical feature to have. The difference between a 1080p set and a 720p/1080i set will also be difficult to distinguish unless you have a very large TV(50+ inches).

Constrast Ratio is the comparison to the whitest white color to the darkest black a set can produce. This will be reported as a ratio such as 5000:1 or 10,000:1. Technically, the higher the number the better. Unfortunately, this has become a stat that many manufacturers play tricks with the make their set stand out among the rest. Some manufacturers measure contrast ratio differently so it is best for you to compare two sets and see which can actually produce darker blacks and brighter whites.

Response time of an LCD is another stat that has been played with by manufacturers to make their set stand out from the rest. Some define this as the time it takes a pixel to go from black to on to black again while others use a grey to grey rating. Again, it is best to look at a set yourself. If it has a slow response time you will see blurring in fast action scenes. Most TV's have a decent enough response time that this is not nearly as important as it was in the past.

I hope this helps you.

Answer 2

Resolution: the total number of pixels that can be displayed. For LCD TVs, a 720p set displays 1280x720 = 921,600 total pixels; for a 1080p set, it is 1920x1080 = 2,073,600. Thus a 1080p set has about twice the resoltion of a 720p set.

Contrast ratio: as given in specs for TV, it is the ratio in intensity between a white screen (pixels fully on) and a black screen (pixels fully off). A 1500:1 contrast ratio means that the black screen is 1/1500 as bright as as the white screen. The higher this number is, the better the picture. The full-screen method is used to spec the sets because it gives the highest number. It is not the most realistic number to represent image quality, which should be an alternating black-white pattern on the screen (more like a real picture). Unless the manufacturer specifies the method of this measurement, you can assume that the full-screen method was used.

Response time in LCD display refers to how fast the pixels can switch from white to black and vice-versa. Each pixel can change its illumination every 1/60 of a second (16.7 ms). If the response time of the pixels is too slow, it may not change fast enough to reproduce changes in the picture. Poor response time shows up as ghost trails on moving objects, and is a serious problem for video game displays. The newest LCD sets have improved greatly in their response times, and are considered satifactory for vidoe games.

Answer 3

Resolution: the total number of pixels that can be displayed. For LCD TVs, a 720p set displays 1280x720 = 921,600 total pixels; for a 1080p set, it is 1920x1080 = 2,073,600. Thus a 1080p set has about twice the resoltion of a 720p set.

Contrast ratio: as given in specs for TV, it is the ratio in intensity between a white screen (pixels fully on) and a black screen (pixels fully off). A 1500:1 contrast ratio means that the black screen is 1/1500 as bright as as the white screen. The higher this number is, the better the picture. The full-screen method is used to spec the sets because it gives the highest number. It is not the most realistic number to represent image quality, which should be an alternating black-white pattern on the screen (more like a real picture). Unless the manufacturer specifies the method of this measurement, you can assume that the full-screen method was used.

Response time in LCD display refers to how fast the pixels can switch from white to black and vice-versa. Each pixel can change its illumination every 1/60 of a second (16.7 ms). If the response time of the pixels is too slow, it may not change fast enough to reproduce changes in the picture. Poor response time shows up as ghost trails on moving objects, and is a serious problem for video game displays. The newest LCD sets have improved greatly in their response times, and are considered satifactory for vidoe games.

Answer 4

Resolution: the detail that can be shown on the screen. most common for HDTV are 720p, 1080i, and 1080p. the best is 1080p, then 720p, and then 1080i. the 'p' mean that the tv is progressive scan, and can therefore put more lines of picture up in less time, making a clearer picture. sure it's a small difference, but it's still slightly noticeable.

Contrast Ratio: numbers such as 2000:1, 5000:1, and 10000:1. the higher the number, the better. This refers to the difference between the darkest blacks and the brightest whites on your screen. The lower the number, the more "muddy" the picture becomes with the whites turning a little grey and the black turning a little dark grey. The higher the number, the sharper the picture.

Fast response time: this also refers to the 'p' on 1080p and 720p because it is progressive scan. It can also be used to differentiate between LCD, plasma, and DLP. DLP is supposed to be one of the "fastest" techologies, presenting a better picture for quick moving events such as sports broadcasts and video games. LCD is also very fast and would come in second in my book. For overall tv viewing i would stick with LCD, the faster the response time the better. Less blurring of the picture, etc.

Hope this all makes sense and helps you out.

Answer 5

Check this website for further informative information:

http://www.soundandvisionmag.com/resources/851/resource-center.html

Click on How to Speak A/V.

I hope this helps.

Reader of Sound and Vision since 1985 (back then it was called Stereo Review).