1. How are horizontal scanning frequency (line rate), vertical scanning frequency (refresh rate) and video bandwidth related?

2. Which of the ViewSonic^® monitors are 110/220 volt switchable?

3. Why do your SonicTron^® monitors have an aperture grille pitch (ag) and the
others have a dot pitch (dp)?

4. What is an Invar shadow mask?

5. Why does my SonicTron monitor have horizontal lines across it?

6. How do I set the resolution and refresh rates of my monitor and what
determines how many colors I can use?

7. What is multi-frequency, autoscanning and GTF?

8. Are ViewSonic monitors Sun^® Workstation compatible? What kind of converter is
needed?

9. What is the difference between an interlaced and non-interlaced mode?

10. What is a SuperContrast screen?

11. How can I download the updated monitor.inf file for Windows^® '95 and '98 from
your website?

12. What is SuperClear Screen Technology?

1. How are horizontal scanning frequency (line rate), vertical scanning frequency (refresh rate) and video bandwidth related?

Maximum horizontal and vertical scanning frequencies are limited by the monitor's electronics and CRT type.  Higher resolutions require higher horizontal scanning frequencies for he same refresh rate.  For example 640x480 @ 75Hz requires 37.5KHz, whereas 1600x1200 @ 75Hz requires 93.8KHz horizontal rate.  Video bandwidth has to increase proportionately in order to clearly display each horizontal dot.  If the video card settings are changed to too high a resolution, it is possible for the monitors maximum horizontal frequency to be exceeded, in which case it will blank, display horizontal lines or an 'Out of Range' message.

2. Which of the ViewSonic^® monitors are 110/220 volt switchable?

All current ViewSonic models have a universal power supply (auto-sensing) to accept AC voltage ranging from 88-108 and 180-264 volts.

3. Why do your SonicTron^® monitors have an aperture grille pitch (ag) and the others have a dot pitch (dp)?

It depends on the type of CRT (Cathode Ray Tube) used in the monitor. All color CRT's use emissions from red, green and blue phosphors to produce images. Most CRT's on the market today employ a shadow mask to ensure correct colour registration. Interspersed red, green and blue phosphor dots are deposited inside the front surface of teh CRT face plate. The dot pattern is such that three adjacent dots of the same color form an equilateral triangle.  The dot pitch (d/p) is the length of one side of the triangle, or because of the pattern the vertical spacing between two like colored dots.  This is usually 0.24-0.28mm.

The shadow mask is a perforated metal plate positioned near the front of the CRT between the red, green and blue electron guns and the phosphors.  The holes exactly line up with the phosphor dots, such that each gun only illuminates dots emitting one color of light, either red, green or blue.  The range of colors required are then produced by varying the intensity of electron emission from each of the three guns as the beams are scanned horizontally and vertically.

In the ViewSonic Sonictron CRT the shadow mask is replaced by a grid of fine vertical wires called an aperture grille (a/g), with the red, green and blue phosphors now arranged in alternate vertical stripes.  Aperture grille (a/g) pitch is the distance between adjacent stripes of the same color.

4. What is an Invar shadow mask?

Invar is a special heat-resistive alloy. The brighter a picture gets, the greater the heat build-up on the mask. If the mask gets too hot it will deform, resulting in a loss of color purity. Our Graphics Series monitors that feature an Invar shadow mask allow images to be 20% brighter than standard CRT's. Our Professional Series monitors with an advanced Invar shadow mask (AIM) allow a 40% increase in brightness over standard CRT's.

5. Why does my SonicTron monitor have horizontal lines across it?

This is a property inherent to this type of CRT.  Damper wires are required to maintain the aperture grille's alignment and will cast a shadow on the screen. In most applications these lines will blend into the background, but they will be visible against lightly-colored screens.  They are thinner than human hair.

6. How do I set the resolution and refresh rates of my monitor and what determines how many colors I can use?

These parameters are set by the video card in your computer. You should have a utility program provided by the video card manufacturer that allows you to install video drivers in your system. Note that your monitor will have limitations as to how high the refresh rate can be set (see Question 1), but there is no limitation to the number of colors your monitor is capable of producing.

If you want to know roughly how much memory you need on your video card, there is a quick formula to calculate this number based on how many colors you require at the resolution you wish to run:

For example, 16.7 million colors (a.k.a "true color") at 1024 x 768 requires:
1024 x 768 x 3 = 2,359,296 bytes (approx. 2.4 MB).

Therefore, a video card with 4MB of video RAM is required since video cards have memory in increments of 1,2,4 and 8 MB (another option is to lower the color depth or resolution, then a 2MB card will suffice).

7. What is multi-frequency, autoscanning and GTF?

Multi-frequency monitors can adjust to different resolutions and refresh rates that are sent from the graphics adapter, providing those signals fall within the monitor's scanning range. The monitor controls may have to be used to adjust the picture size and position. Autoscanning monitors provide constant screen size across different applications and environments. Autoscanning automatically adjusts the screen at the start of each application to a pre-defined screen setting determined by the video mode of the application.

GTF or 'Generalised Timing Formula' is a standardised range of video timing formats.  A 'GTF' monitor is designed to give a correctly sized and centered picture when presented with a GTF timing, with no adjustments required by the user.

8. Are ViewSonic monitors Sun^® Workstation compatible? What kind of converter is needed?

Yes, as long as you have our Sun Workstation adapter. This adapter converts the 15-pin Mini D-Sub connector from the monitor to the 13-pin connection on the Sun Workstation. The part number is SW1152 and can be purchased from ViewSonic.

9. What is the difference between an interlaced and non-interlaced mode?

Interlaced is a technology used in a standard television display. The electron gun will draw the odd numbered lines from the top to the bottom of the screen, then will come back to the top and draw in the even numbered lines. Flickering occurs because the non-refreshed lines fade before they are redrawn. In the non-interlaced mode, the screen is drawn from top to bottom, line by line, which produces less flicker and less eye strain for the user.  Non-interlace timings are now standard for computer display timings.

10. What is a SuperContrast™ screen?

A SuperContrast screen uses glass which has a lower transmission rate. A lower transmission rate leads to each pixel being more distinct, producing richer colors and sharper contrast.

11. How can I download the updated monitor.inf file for Windows^® '95 and '98 from your website?

Click here to download the latest .inf file.

12. What is SuperClear™ Screen Technology?

SuperClear offers up to 30% more brightness and contrast due to the addition of microfilters than conventional CRTs

Sample Factory Preset Timings:
(PT771

Timing	Horiz. Freq. (kHz)	Vert. Freq. (Hz)	Polarity (H/V)
1. VESA® 640 x 400	31.47	70.00	-/+
2. Ind VGA 640 x 480	31.47	80.00	-/-
3. VESA 640 x 480	37.50	75.00	-/-
4. VESA 640 x 480	43.28	85.00	-/-

5. VESA 800 x 600	35.13	56.00	+/+
6. VESA 800 x 600	46.87	75.00	+/+
7. VESA 800 x 600	53.68	85.00	+/+
8. VESA 1024 x 768	48.34	60.00	-/-
9. VESA 1024 x 768	60.00	75.00	+/+

10. VESA 1024 x 768	68.68	85.00	+/+
11. VESA 1280 x 1024	63.96	60.00	+/+
12. VESA 1280 x 1024	79.96	75.00	+/+
13. VESA 1280 x 1024	91.12	85.00	+/+
14. VESA 1600 x 1200	75.00	60.00	+/+

15. VESA 1600 x 1200	87.50	70.00	+/+
16. Mac® 640 x 480*	35.00	67.00	-/-
17. Mac 832 x 624*	49.71	75.00	-/-
18. Mac 1024 x 768*	60.24	75.00	-/-
19. Mac 1152 x 870*	68.65	75.55	-/-

* These Macintosh^® frequencies are Sync-On-Green or Composite Sync