Weak current College】 【projection common glossary --- Power By】 【China power house network.

<br> (1) aspect ratio <br> Intuitive image or projection image width and height ratio. <br> The aspect ratio of HDTV standards is now 16: 9 (wide screen available rectangular image). Analog TV and TV programs of the .United States national television standards Committee (NTSC) standard is 4: 3 (traditional square format). <br> <br> (2) aging <br> Screen permanently damage in some regions, due to the still images continuously displays a long time .. <br> <br> (3) contrast ratio <br> Image contrast ratio refers to the image of a very bright and very dark parts of the section. Contrast high allows TV to light a very strong case still good work, and display .of colors is very delicate. <br> <br> (4) Dolby Digital sound system <br> Popular 5.1 channel home theater sound system, includes left surround speaker; right, left, front, speaker, and LFE (low frequency effects) .channel. <br> <br> (5) DLP technology <br> DLP technology in a large number of projection and display application provides as clear as Crystal, sharp and smooth images, including projector, home entertainment projectors, big screen HDTV, video .wall and in use in Commerce, entertainment and other projection system. DLP Cinema technology provides large-screen image in many ways better than the current movie, is driving the evolution of the film industry. <br> <br> Each of the DLP ® .projection system's core is called DLP chip optical semiconductors, it serves as the exception precise optical switch. DLP chip contains over a million hinged micro-lens. By switching the mirror, DLP projection system can provide vivid, sharp and smooth image. <br> .<br> (6) HDTV (high definition TV) <br> HDTV is a new television standard that uses digital signals instead of analog broadcast television standards currently. HDTV signal level contains more than 700 lines of resolution, while the analog signals can only .provide the 525 lines of resolution. HDTV also is moving rectangle wide screen format (16: 9) development to get a true cinema-like experience. <br> <br> HDTV image will transmit signals before digitization and compression to make them easy to .transport of huge amount of information. When these signals reach the TV, just decompressed. <br> <br> (7) resolution <br> Image resolution is to generate image vertical segment of the total number of horizontal rows stacked. The higher the .resolution, the image is clearer and more delicate. Standard TV signal generally 525 lines of resolution. However, the HDTV signal contains more than 700 lines of resolution, so the generated outstanding image quality. <br> <br> (8) viewing angle .<br> Available from off-center point of the view most of the image. <br> <br> (9) the number of split-screen <br> The number is a multiple-split screen display card is one of the most .important indicators, which represents a multi-screen display card to connect up to the number of the monitor. Multi-screen display card of split-screen is not a simple multiple monitor displays multiple identical content, but rather multiple screen displays a different screen, .and displays a combination of large screen splicing. For example, the number of 4-screen multi-screen display card can connect 4 monitors, you can let this 4 monitors are part of the display, together with a picture, or you can let this .4 monitors each show a different picture. General multi-screen display card number is split-screen two or four, if you need to connect more monitors, you can in one computer connection multiple multi-screen display card. <br> <br> .(10) brightness uniform value <br> Refers to the lightest and darkest parts of the differences in value, is projected to a screen projector, its four corners of the brightness and the center point of the brightness ratios, General of the intermediate as 100 .%. Any projector projected images appear Center area and the four corners of the luminance uniformity of different phenomena, reflects the edge brightness differences with the Centre, with luminance percentage. Of course, the ideal uniformity is 100%, the higher the screen uniformity of .brightness consistency, the better. For projectors, image uniformity of critical factors is the optical lens imaging quality. Simple present the projector screen uniformity of are in more than 85%, some excellent projector can reach 95%. <br> <br> ( .11) screen size <br> Refers to the cast of screen size, the smallest image size and the maximum image size, generally expressed by diagonal size, unit is inches. This indicator is a projection optical zoom performance decisions, to put the intended size ., the projector is placed in the appropriate distance from the screen. According to the various scenes and brightness projector, screen size and projection distance relationship differ. Generally speaking, the higher brightness projector can vote out the larger screen, projector according to the lens has .a minimum screen size and maximum screen size, the size of the screen between the projector projection can clear focus, if you exceed this range, the screen may appear unclear and drop shadow effect is very poor. <br> <br> (12) .the projection distance <br> Refers to the projector's lens and the distance between the screen, usually of rice to as units. In a real application, in a small space to get the big picture, you need to use with a wide angle lens of .the projector, so that you can in a short projection distances for a large projection screen size; in the theater and auditorium environment projection distance, to obtain the appropriate size of the screen, you need to select with long focal lens of the projector, so .that you can in the long projection distance can also be given the right screen size, not image too large to exceed the screen size. Ordinary projectors for standard lens, suitable for most users. <br> <br> (13) the number of .colors <br> Number of colors is the screen displays up to the total number of colors. On the screen of each pixel, 256 colors to use 8-bit binary number indicates that 2 of the 8-th power, so we put the 256 .-color bitmap graphics called 8; if the color of each pixel in 16-bit binary number that IThey call it 16 bitmap, it can express 2 of 16 th 65536 color; there are 24-bit color figure, can express 16,777,216 color. Now .most projectors support 24-bit true color. <br> <br> (14) the projection mode <br> Positive vote: will the projector upside down hanging in front of the projection screen. <br> <br> <br> < .br> Rear-projection: projection on the back of the screen for projection. <br> <br> <br> <br> (15) trapezoid correction <br> The daily use of the projector, the position of the projector and projection .screen as much as possible to angles in order to guarantee the drop shadow effect (below) If you are unable to guarantee both vertically, the screen will produce a trapezoid. In this case, users need to use "trapezoidal correction function" to correct the .trapezoid, ensure the screen into a standard rectangle. <br> Trapezoid correction usually has two methods: optical trapezoid correction and digital keystone correction, optical trapezoid correction refers by adjusting the lens's physical location to achieve the purpose of adjusting the trapezoid, another digital keystone .correction is through a software method to implement a trapezoid correction. <br> <br> <br> <br> <br> <br> At present almost all of the projector manufacturers have adopted the digital keystone correction technology and digital keystone correction of .most projectors support vertical keystone correction function, that is, the projector is vertically adjustable height of itself, resulting in a trapezoid, through the projector vertical keystone correction, you can make the image into a rectangle, so as to facilitate the use of the user .. <br> But in practice, in addition to vertical keystone correction, you often come across because of the projector horizontal position of bias arising from the trapezium. Many projector manufacturers have developed "horizontal keystone correction function". Horizontal keystone correction and vertical keystone .correction are digital keystone correction through software interpolation algorithm display the first image shape adjustment and compensation. Horizontal keystone correction solves projector lens and the screen cannot be vertical and horizontal direction trapezoid distortion of the image, so that the projector to the side of the screen or .you can also implement the standard rectangular projection image. <br> Digital keystone correction for image accuracy is not high, it can be a good solution to the problem of trapezoidal distortion, usability is very strong, but for those who have image precision demanding application .is not very appropriate. Because the image after the correction, the display of the number of lines and characters edge deburring and appears not smooth, lead definition is not particularly good. <br> (16) bandwidth <br> Bandwidth is the monitor video .amplifier passband width ", means the gun on the screen every second sweep the maximum number of total pixels to MHz (megahertz). On the surface, simply multiply the horizontal resolution row frequency can be bandwidth. But in fact, gun while scanning across the .horizontal direction of pixel count and vertical pixel count is higher than the theoretical value, so as to avoid signal attenuation in scan edges, so that the same clarity around the image. <br> Horizontal resolution of about actual scan value of 80%, vertical .resolution about the actual scanning of 93 per cent of the value, so bandwidth is: bandwidth = horizontal resolution/0.8 × vertical resolution/0.93 × field frequency. Or bandwidth = horizontal × vertical resolution × field frequency × 1.344. For example: in a .1024 × 768 2048x1536 @ 85hz mode, the bandwidth is 1024 × 768 × 85 × 1.344 = 89.84199868mhz. Bandwidth of a higher value, the better the performance monitor. <br> The higher the bandwidth, the smaller the inertia, respond faster, .allows the higher the frequency of the signal, the signal is distorted, it reflects the monitor's resolution. Compared with row frequency, bandwidth and a more comprehensive and more direct reflection of the monitor's performance. It exposes the monitor performance difference of one of the more .important factors. <br> Bandwidth determine one monitor can handle a range of information, it refers to a specific electronic device can handle the range of frequencies. Working frequency range early in the circuit design will be qualified, because of the high-frequency radiation ., and therefore will have high-frequency processing circuit design more difficult, the cost is much higher. And enhance the high-frequency processing capability can make the image clearer. Therefore, wideband can process more frequently, the image is better. Each resolution corresponds .to a minimum acceptable bandwidth. If bandwidth is less than the resolution of acceptable values, the image will show up as a result of loss and distortion and blur. <br> The following table lists some common resolution and refresh rate under acceptable bandwidth: < .br> <br> <br> <br> (17) standard <br> Video signal is an analog signal, the video simulation data and video synchronization data constitute, for the receiving end can correctly display the images. Signal details depend on the .application of video standard or "standard" - NTSC (national television standards Committee of the United States, the National Television Standards Committee) and PAL (Phase Alternate Line) and SECAM (sequential transfer and store color TV system, France adopted a SECAM, .SEquential Couleur Avec Memoire). In the PC field, the use of standard, there are not compatible. Take the resolution, of each frame has a 625-line (50Hz), then each frame only 525 lines (60 Hz). The latter .is used in North America and Japan, are collectively referred to as NTSC standard. Typically, a video signal is generated from a video source, such as camera, VCR or TV tuner, etc. To transfer images, video source must first build a vertical .synchronization signal (V SYNC). This signal will reset the receiver devices (PC monitor), make sure that the new image from the top of the screen is beginning to show. VSYNC signals issued, video source then scanned images of the first row. .Completed, the video source also generates a horizontal sync signal to reset the receiver to the left of the screen displays the next line. And for each row of the image, all roundsA scan line and a horizontal sync pulse signal. <br> <br .> In addition, the NTSC standard also provides video source needs to be sent per second 30 sites full of images (frames). If not otherwise dealt with, flashing phenomenon can be very serious. To resolve this problem, and each frame is divided into .two parts, each part 2 62.5 rows. Part of all the odd lines and partly all even-numbered rows. Display, first scan the odd-numbered rows, and then scan the even-numbered rows, you can effectively improve the stability of the .image display, reduce flicker. At present, there are three main color television standard, ie NTSC, PAL and SECAM format, three standard is not uniform. China is PAL-D format. Above is compatible with the General plasma TV format. <br .> <br> (18) memory capacity <br> Memory capacity is local video memory on the video card's capacity, this is the choice of one of the key parameters of the video. RAM size determines the memory capacity of the temporary storage of data ., to a certain extent also affect the performance of the video card. Memory capacity is as graphics development and gradually increasing and more and larger trends. Memory capacity from early 512KB, 1MB, minimal capacity 2MB etc to 8MB, 12MB, 16MB, 32MB, .64MB, until the current mainstream 128MB, 256MB and high-end graphics cards, graphics cards, some professional 512MB even with 1 GB of graphics memory. <br> <br> Maximum resolution of the video card, the maximum resolution, to some extent ., have a direct relationship with video memory, because the pixel data is initially stored in video memory, so the video memory size affects the maximum resolution. In the early days of video memory size simply 1MB with 512 KB, and so on very small, .2MB capacity, memory capacity is the maximum resolution of a bottleneck; but now the mainstream video card RAM, even 64MB has been eliminated, mainstream entertainment-class video card is already a 128MB, 256 MB or some professional graphics 512MB, even with 1 GB .of graphics memory, in this case, the video memory capacity earlier is no longer a maximum impact. <br> <br> In graphics performance, with the display chip can handle more and more powerful, especially now that large 3D gaming and professional rendering .needs to temporarily store data more and more, the required memory capacity is growing, memory capacity, to some extent also affects the video card's performance. For example, shows a strong core and memory capacity sufficient to relatively small, but there are plenty of great .texture mapping data needs to be kept, if the memory capacity sufficient to hold the data, then show the core in some time only idle waiting for the data processing is complete, this affects the display of the core performance play thus affects the performance of the .video card. <br> <br> It is important to note that the greater the memory capacity does not necessarily mean that the higher the video card performance, since the decision of the three elements of the video card performance is the first of which are .in a display chips, followed by the video memory bandwidth (depending on the graphics memory bandwidth and memory frequency), the last is the memory capacity. A video card should be equipped with a large memory capacity is suitable is determined by its display chip used .in the decision, that is, memory capacity should display to match the performance of the core before it is reasonable, the higher the display chip performance due to its higher processing power with the memory capacity, the greater the corresponding should also, and the low .performance of the display is equipped with a large-capacity memory chips on its properties is of no help. For example, sales of some equipped with a large capacity memory of 512MB Radeon 9550 graphics in graphics performance with the Radeon 9550 128MB graphics video card on .core frequency and memory frequency and other parameters are the same is exactly the same, because the Radeon 9550 graphics core relative low processing power determines its equipped with large-capacity memory is meaningless, and large-capacity memory but also brought the issue of purchase costs .. <br> <br> (19) DirectX <br> DirectX is not a simple graphics API, which is Microsoft's development of a wide range of uses of the API, it contains Direct Graphics (Direct 3D + Direct Draw), Direct Input ., Direct Play, Direct Sound, Direct Show, Direct Setup, Direct Media Objects and other components, it provides a complete set of multimedia interface programmes. Is it in 3D graphics, excellent performance, it is looked for other areas. DirectX development beginning in .order to compensate for Windows 3.1 system on graphics, sound processing, and have now become on the whole the various aspects of the multimedia system has a decisive influence on the interface. <br> <br> (20) MPEG4 <br> MPEG ( .Moving Picture Experts Group moving picture experts group) is the International Organization for Standardization (ISO) dedicated for moving picture coding standard working group, the standard is the international common criteria, called the MPEG standard, the standard by video, audio and system made up .of three parts. VCD MPEG1 is video image compression standard; MPEG2 is the Super VCD DVD / video compression standards; MPEG4 network video compression standard, features a high compression ratio, the image is clear, a disc that can store DVD-9 10 more .high-definition movie MPEG4 network. <br> <br> MPEG4 video compression algorithm can provide very high compression ratio of up to 200: 1. More importantly, MPEG in providing high compression ratio, data loss is very small. MPEG4 is the latest .MPEG image compression technology standards. It can be said that the challenge DVD to SVCD, under force pressure on DVD and SVCD threat from self-evident (some say it isDVD killer). It is said that MPEG4 is the United States prohibits the export of .coding, it is used to encode and compress a DVD only need two pieces of 2 CDROM. Besides playing (unzip) the code on the machine's hardware requirements are not high. <br> <br> (21) sensitivity <br> To guarantee .the required error rate conditions, receive the required minimum input power. Receiver sensitivity to general use dBm, it is to lmW optical power-based absolute power, or write to <br> <br> Of these, Pmin refers to the given error rate ., the receiver can receive the minimum average power. For example, in the given error rate of 10 negative 9 th, the receiver can receive the minimum average power for InW (ie 10 negative 9 th W), receiver sensitivity of-60dBm. < .br> (22) horizontal scan frequency <br> Also known as horizontal refresh rate, it refers to monitor every second of the scan line number, measured in KHz. Row frequency = rows * field frequency, for example in 800 * 600 resolution, .refresh rate 85Hz (usually expressed as 800 * 600 @ 85Hz), row frequency = 600 * 85Hz = 51Khz. <br> <br> Dots (23) <br> LCD display of the pixel pitch (pixel pitch) of significance similar to .CRT dots (dot pitch). Dot pitch generally refers to display adjacent two pixel distance between a point. We see that the picture is composed of many of the points, but the picture is composed of dots xinidu to decide, the dots in the calculation .is based on the panel size is divided by the value of resolution, but the dots for LCD product performance of importance but far from being as high as for the latter. <br> <br> The dots will because the CRT shadow or gratings design ., video card type, vertical or horizontal scan frequency to be changed, but the number of pixels LCD monitor is fixed, so in the same size and resolution of cases, most of the LCD display of the pixel pitch is basically the same. Resolution of .1024 × 768 of 15 inch LCD monitor, its pixel spacing are 0.297mm (there are some products labeled 0.30mm), and 17 inch Basic for 0.264mm. So for the same size of LCD prices generally has nothing to do with the dots in .Basic. <br> <br> (24) the multi-screen display <br> Multi-screen display card is designed for today's PC deeper application requirements and the design of high-performance multi-screen card. It allows a single PC support .multiple VGA monitor, TV or DVI digital flat panel display, it is designed for today's graphic image applications, particularly in windows under a variety of operating parameters in the development, design, edit, control, multimedia. <br> <br> Multi- .screen display card is not a simple multiple monitor displays multiple identical content, but rather multiple screen displays a different screen, and displays a combination of large screen splicing. For example, the number of 4-screen multi-screen display card can connect 4 monitors ., you can let this 4 monitors are part of the display, together with a picture, or you can let this 4 monitors each show a different picture. Mouse and window can also roam between each screen mobile, without any changes to the software. < .br> <br> Multi-screen display card widely used: control, command and control system; police, fire, military, meteorology, railway, aviation and other monitoring systems, video conferencing, query system, etc..