Posted by matt(v) on September 07, 1999 at 16:11:00:
In Reply to: Arcade monitor refresh rate (vertical) posted by Tom61 on September 07, 1999 at 15:34:15:
: what is the vertical (would be in Hz not kHz) refresh rate of an arcade monitor?
: I found out my video chip (on the motherboard) can down very low in the refresh rate. I don't know about my Voodoo2 though.
: I was thinking 60Hz was it, just like a TV (NTSC), but that's interlaced. And since most people need some util to lower the refresh rate, that 60Hz is to much (default Win drivers run at 60Hz)
Monitor Resolution
The vast majority of videogames utilize what is known as "standard resolution" monitors. Standard resolution monitors conform closely to the NTSC television standard. NTSC stands for the National Television System Committee, the organization which created the standard format adopted by the FCC for broadcast television in the United States. NTSC is also the standard used in Japan, Canada, and Mexico.
Since the first videogames actually used modified consumer television sets, it is natural that the NTSC standard was adopted as a defacto standard for our industry. A normal, NTSC television picture is made of 525 horizontal lines. You don't actually see all 525 lines on the screen. Some of the lines occur during what is known as the "vertical retrace," the time period during which the scanning electron beams make their way from the bottom of the picture tube back up to the top. During the vertical retrace time, the beams are turned off by the monitor's "blanking" circuit and you lose approximately 22 lines.
In fact, NTSC's standard resolution really displays only 240 lines at a time! In your normal television at home, the number of lines you see on the screen is doubled by a technique known as "interlaced raster." The monitor first displays a "field" of 262.5 lines, followed by a second field of 262.5 lines. The lines of the second field are placed in-between the lines of the first field. It takes almost exactly 1/60 of a second for the scanning beam to paint one field on the screen, so the vertical scan frequency is 60 cycles per second or 60 Hertz. (For you purists out there, the vertical frequency is actually 59.93 hz)
The two fields are broadcast successively to create one "frame" of video. The "frame rate" of NTSC is 30 per second. Even though the picture is made of 525 lines (of which only 480 are visible due to the vertical retrace and blanking,) standard NTSC has a "resolution" of just 240 lines. That is to say, the monitor actually displays just 240 lines at a time on the screen; That's one complete field of video.
Since the horizontal deflection circuit of the monitor must create 262.5 lines during the time that the vertical deflection circuit creates a single field, the horizontal deflection circuit must be working 262.5 times faster. The frequency of the horizontal deflection circuit is 15,734 Hertz. If you can hear the high-pitched squeal that a monitor makes when it's on, you're listening to the horizontal frequency.
Stolen from randyfromms technical department http://randyfromm.com/techdept/