- Wondering whether your projector can handle running at "double DVD" resolution?

- Considering adding a video interface and want to know what bandwidth you'll need?

-Try this calculator to get some data to guide your decision.

How to Use the Calculator:

The calculator needs three pieces of information.  The first two are the horizontal and vertical resolution of your intended signal, for example: 800 x 600 (SVGA) or 1024 x 768 (XGA) or 848 x 600 (WXGA), in each of these examples the first number is the horizontal resolution, the second is the vertical resolution.  The third parameter is the refresh rate, or how often the display is updated, in Hz or updates per second.  If you intend to use an interlaced signal (like 1080i or 480i), enter half the full frame update rate to get a correct answer.

Basis for Calculations:

The bandwidth calculation is based on the formulas presented in Extron(TM) Electronics technical paper, "Video Bandwidth".  The results obtained are very conservative; the calculations do not account for filtering or other bandwidth limiting techniques.

Interpreting the Results:

The calculator calculates the following:

-Total Pixels: Simply the product of the horizontal and vertical resolutions, the total number of pixels per frame.

-Horizontal Scanning Frequency: This is the minimum scanning frequency required to display the input resolution at the input refresh rate.  This is the minimum horizontal scanning frequency required for a fixed panel (non CRT) display to reproduce this signal.

-Horizontal Scanning Frequency with Retrace: Adds a factor to account for the additional scanning frequency required by CRT based displays to retrace between frames.  Note this is an estimated value.

-Required Video Bandwidth: This is three times the highest frequency that will be present in the specified signal.  Each component in the video reproduction chain (including cables) should have an upper frequency limit (-3dB point) higher than this value to avoid degrading the image.  When video bandwidth is exceeded images look soft or smeared.

VIDEO SIGNAL BANDWIDTH & HSCAN FREQUENCY CALCULATOR
Horizontal Resolution: Pixels
Vertical Resolution: Pixels
Vertical Refresh Rate: Hz
RESULTS
total pixels per frame
KHz Horizontal Scanning Frequency Required (No Retrace)
KHz Horizontal Scanning Frequency Required (With Estimated Retrace)
MHz Bandwidth Required

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