Extron electronic IN1403 manual CRT displays Selecting the optimal refresh rate

CRT displays: Selecting the optimal refresh rate

CRT displays may tend to flicker at refresh rates below 70 Hz In order to achieve a solid, flicker-free image, an output refresh rate of 72 Hz or 75 Hz is recommended for most CRT displays. You should also experiment with even higher refresh rates to see if they create a better image. In some cases, you will find that the image suddenly appears better at a higher refresh rate, such as 85 Hz

Keep in mind that as the refresh rate is increased, the horizontal scan rate also increases. This places greater higher bandwidth demands on the video distribution system and the display device. If you select a refresh rate that is too high you will actually see a softer image because the signal is exceeding the bandwidth capabilities of the display device. Extremely high refresh rate settings may also create a compatibility problem because a very high refresh rate may result in a signal that is outside the compatible scan rate of the data display.

Fixed pixel displays: Selecting the optimal resolution and refresh rate

Display devices based on LCD, DMD, D-ILA/LCOS, or plasma technology have a specific number of display elements, or pixels. This is also referred to as the "native resolution" of the display device. These devices are usually capable of showing higher or lower resolution signals, but can only do this by scaling the image up or down to the native resolution. In order to avoid additional image scaling it is important to know the native resolution of your display device.

Check your operation manual or the chart on page 17 to determine the native resolution of your display device. The video scaler output should be set to match this native resolution. The video scaler output refresh rate should be set to 60 Hz with most LCD, DMD, LCOS, and plasma displays. Higher refresh rates are not recommended with these display technologies because they usually do not improve the image and may actually cause compatibility problems.

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