سیستم تلویزیون سیستم تلویزیون جلسه هفتم : واحد نمایش رایانه ( مانیتور ) امید رضا معروضی دانشگاه شاهرود

صفحه نمایش اشعه کاتدی Invented in 1897 by Karl Ferdinand Braun Standard for televisions until recent years

نحوه کار صفحه نمایش اشعه کاتدی A=cathode B=conductive coating C=anode D=phosphor-coated screen E=electron beams F=shadow mask Uses R,G,and B phosphors The three beams are accelerated and focused by the anode

رابط مانیتور با کارت گرافیک VGA CABLE VGA Cable- a three-row 15-pin connector. VGA connectors and cables carry analog component RGBHV (red, green, blue, horizontal sync, vertical sync) video signals. The 15-pin VGA connector is found on many video cards, computer monitors, and some high definition television sets. On laptop computers or other small devices, a mini-VGA port is sometimes used in place of the full-sized VGA connector.

آرایش پایه ها درکابل مانیتور

جاروب صفحه نمایش

فرکانس نمایش قاب

پیکسل

فرکانس جاروب و دقت تفکیک Refresh CRT Beam of electrons hit phosphor-coated screen, light emitted by phosphor Direct electron beam to the same screen repeatedly, keeping phosphor activated The frequency at which a picture is redrawn on the screen is referred to as the “refresh rate” The maximum number of points that can be displayed on a CRT is referred to as the “resolution”

Raster-Scan Displays – Picture information stored in refresh (frame) buffer The number of bits per pixel in the frame buffer is called depth or bit planes Buffer with 1 bit per pixel – Bitmap Buffer with multiple bits per pixel – Pixmap – Interlaced refresh procedure Beams sweeps across every other scan line دقت اطلاعات رنگ پیکسلها

بافر تصویر A frame buffer is characterized by size, x, y, and pixel depth. the resolution of a frame buffer is the number of pixels in the display. e.g. 1024x640 pixels. Bit Planes or Bit Depth is the number of bits corresponding to each pixel. This determines the color resolution of the buffer. Bilevel or monochrome displays have 1 bit/pixel 8bits/pixel -> 256 simultaneous colors 24bits/pixel -> 16 million simultaneous colors

تخصیص رنگ مستقیم direct color : – each pixel directly specifies a color value e.g., 24bit : 8bits(R) + 8bits(G) + 8 bits(B) palette-based color : indirect specification – use palette (CLUT) e.g., 8 bits pixel can represent 256 colors 24 bits plane, 8 bits per color gun = 16,777,216

پالت رنگ

ارتباط واحد گرافیک رایانه از باس عمومی Organization of raster system – Fixed area of system memory reserved for frame buffer which can be directly accessed by video controller CPU System Memory Video Controller Monitor System Bus I/O Devices

نقش کارت گرافیک رایانه Video Controller – Refresh operations X, Y register used to indicate pixel position Fix Y register and increment X register to generate scan line – Double buffering Pixel value can be loaded in buffer while Provide a fast mechanism for real-time animation generation

GPU ساختار گرافیک رایانه بر اساس Raster-Scan Display Processor – Free the CPU from the graphics chores – Provide separate display-processor memory – Fig. Architecture of raster-scan display system with display processor CPU System Memory Display Processor System Bus I/O Devices Display Processor memory (Frame Buffer) Video Controller Monitor

سیرتحول استانداردهای صفحه نمایش

مانیتورهای سیاه و سفید Monochrome Display Adapter (MDA) was the first video card created in 1981 – displays green text on black screen

VGA مانیتورهای رنگی Video Graphics Array (VGA) = very popular and was the standard in almost every PC up until recently

کارت گرافیک

اجزاء کارت گرافیک Graphics Processing Unit (GPU): perform calculations for rendering and figure out what to do with each pixel Video Memory: storing images and information about each pixel Output: Common outputs include Video Graphics Array (VGA) for CRT monitors, Digital Visual Interface (DVI) for flat panel displays, and Video-in-video-out (ViVo) for television and video cameras

اجزاء کارت گرافیک ( ادامه ) Heat sink and Fan: used to cool the GPU, just like the CPU of a computer having the same cooling instruments Motherboards: PCI before AGP Motherboards: Accelerated Graphics Port (AGP) compatible popular decade ago; Peripheral Component Interconnect Express (PCI-E) gaining popularity BIOS chip that stores settings, information about each component of the graphics cards, and can be altered for over-clocking

نحوه کار کارت گرافیک Take data from CPU and figure out what to do with each pixel to create image Create wire frame using vectors Fill remaining pixels with color, lighting, and texture The filling will consider viewpoint For games and video, the graphics cards has to do the above steps for 30 frames per second

نحوه کار کارت گرافیک ( ادامه ) In greater detail: – GPU creates image, stores image with location and color of each pixel in memory – Memory also holds completed images until it’s time to display them (frame buffer) – Digital-to-analog converter (DAC) is connected to memory and translates image into analog signals that is sent through monitor cable and the image is displayed on monitor

صفحه نمایش دیود نوری Field emission displays, electrons coming from millions of tiny microtips pass through gates and light up pixels on a screen. This principle is similar to that of cathode-ray tubes in television sets. The difference: Instead of just one "gun" spraying electrons against the inside of the screens face, there are as many as 500 million of them (microtips).

ماتریس سوئیچ The cathode/backplate is a matrix of row and column traces. Each crossover lays the foundation for an addressable cathode emitters. Each crossover has up to 4,500 emitters, 150 nm in diameter. This emitter density assures a high quality image through manufacturing redundancy, and long-life through low operational stress.

تابش نور Emitters generate electrons when a small voltage is applied to both row (base layer) and column (top layer).

ساخت ماتریس پیکسلها Faceplate picture elements (pixels) are formed by depositing and patterning a black matrix, standard red, green, and blue TV phosphors and a thin aluminum layer to reflect colored light forward to the viewer.

درگاه های کنترلی فلزی

صفحه نمایش پلاسما invented at the University of Illinois at Urbana- Champaign in 1964 for the PLATO Computer System 1983 IBM introduced 19” orange on black monochrome Gas made up of free flowing ions and electrons

نحوه کار صفحه نمایش پلاسما Made up of tiny fluorescent lights Each pixel contains a red, green, and blue light xenon and neon gas is contained in hundreds of thousands of cells positioned between two plates of glass along with electrodes When charged, it releases ultraviolet photons which act with the phosphors This brings their energy level up, when it goes back down it is released as visible light photons

صفحه نمایش دیود کریستال مایع Liquid crystals were first discovered in 1888, by Austrian botanist Friedrich Reinitzer First experimental LCD by RCA in 1968 Based on properties of polarized light

نحوه کار صفحه نمایش دیود کریستال مایع Formed by two glass layers called substrates One is in charge of columns, and the other is in charge of rows Liquid crystals are sandwiched in between these two layers Uses a grid to charge specific pixels When this happens the crystals untwist and allow light to pass through

صفحه نمایش پردازشگر نور دیجیتال Developed by Texas instruments Created by Dr. Larry Hornbeck in 1987

نحوه کار صفحه نمایش پردازشگر نور دیجیتال One DLP chip contains more than 2 million mirrors Each mirror made of aluminum represents one pixel on the screen The chip will rapidly decode a bit- streamed image code that enters through the semiconductor It changes the data from interlaced to progressive scanning and adjusts the picture The mirrors then tilt off and on to allow light to pass and can do it up to 5,000 times per second The is then sent through a transparent, spinning color wheel that is synchronized with the chip into red, green, and blue, light, and can produce 16.7 million colors

رابط صفحات نمایش مسطح با کارت گرافیک DVI CABLE DVI Cable- (Digital Visual Interface) is a video display interface used to connect a video source to a display device, such as a computer monitor. The interface is designed to transmit uncompressed digital video and can be configured to support multiple modes such as DVI-D (digital only), DVI-A (analog only), or DVI-I (digital and analog).

DVI آرایش پایه های کابل

The DVI connector is divided mainly into three areas: TMDS. (Transition Minimized Differential Signaling) or Transition Minimized Differential Signal similar to communication systems balanced. Marked on the figure by the brown color has four twisted pair cables one for each primary color video red, green and blue. Each two pairs have a mass of specific protection marked in dark brown. The video signal is synchronized with a pair of twisted wires in light brown line has its own mass. With a video link can transmit high-definition HDTV signal (1920 × 1080) at 60 Hz (139 MHz) for better definitions and better refresh the DVI connector includes a second link in combination with the former provides resolutions higher than HDTV HDTV (1920 × 1080) at 85 Hz (2 × 126 MHz) or WQXGA (2560 × 1600) at 60 Hz (2 × 135 MHz), among others. Pug & Play. Marked in blue has a number of lines that highlight the DDC (Display Data Channel), serial connection with pin I2C Bus SDA (data) and SCL (clock). Are used to detect and display settings when connecting to a computer. Analog. Analog system, marked in green features a pin (pin) for each RGB primary color red, green and blue analog sync with the digital connector makes it compatible with the analog system, reaching a bandwidth of 400 MHz DVI آرایش پایه های کابل