Tech Tip
	Date: 04/04/97

1024 x 768 External Monitor Mode
“Fuzzy” Display 

Product:  		DIGITAL HiNote Ultra II, HiNote VP, VP 500 series, VP 700 series & Ultra 2000 series
Part # Affected:  	HiNote Ultra II family   	FR-P8EWG-xx, FR-P8GWG-xx, 
FR-P8MWG-xx, FR-P8OWG-xx.
		    			  	FR-P8FWG-xx, FR-P8HWG-xx, 
FR-P8NWG-xx, FR-P8PWG-xx.
		    	HiNote VP family   	FR-PA5WF-xx, FR-PA6WF-xx, 
FR-PABWF-xx, FR-PACWF-xx.
		    	HiNote VP500 family  	FR-PB1WF-xx, FR-PB3WF-xx, FR-PB4WF-xx, 
              		FR-PC1WF-xx, FR-PC3WF-xx, FR-PC4WF-xx.

DIGITAL VP700 Series	FR-PK1WI-**
			FR-PJ2WI-AA
						FR-PK2WI-AA
			FR-PJ4WI-AA
						FR-PK4WI-AA

Ultra 2000	FR-PG3WI-XX			
    						FR-PG4WI-XX
						FR-PG4WJ-XX
			FR-PG5WK-XX
						FR-PG7WK-AA
			FR-PG6WK-XX
			
Affected Period:  	N/A
OS Type and Version:  N/A
ECO/FCO Issued:  	N/A

Summary:  
Some customers have reported that when using their systems with an external monitor on 1024x768 resolution mode they experience a fuzzy display.  The characters are not crisp and clear especially when they compare it to another notebook from other vendors.

Customer Response:
DIGITAL has recognized that there is a possibility of customers experiencing the Fuzzy display when connecting to external Monitors at 1024 x 768 resolution with the HiNote Ultra II, HiNote VP , VP500 series , VP 700 series & Ultra 2000 Series. product families.  Several customers have reported a dissatisfaction with their Digital notebook in the external display quality display for applications that require a 1024x768 resolution.  The situation is worse when the display size increases due to the enlargement of the characters on the screen, i.e. a 15” monitor will appear to be slightly out of focus where a 21” monitor will appear very fuzzy.  Some customers have reported that they believe that the screen has caused them eye strain or headaches from this issue.

Description:  
Customers have reported that when using a HiNote Ultra II, HiNote VP , VP500 series , VP 700 series & Ultra 2000 series with a monitor attached they experience a “Fuzzy” video display.  This appears on when using external 1024x768 resolution.  The details of the issue are that in VESA modes 34h, 52h, and 74h, the maximum vertical refresh rate is 85Hz.  At 85Hz, the dot clock should run at 94.5MHz, each pixel requiring approximately 15nS speed on the signal.  When there is a sharp color discontinuity, such as at the edge of a vertical line, the crispness of the edge is determined by the speed with which the video intensity signal rises from low to high.  Monitor Engineering tested the rise and fall times of a ProjectX machine set for video mode 34h, with timings chosen for monitors capable of 85Hz vertical refresh rates.   With the desktop background  cleared to white, the edges of the screen provided a suitable test for rise and fall times.  The rise time (10% to 90%) was measured to be 20nS (probable error: ±1nS).  The acceptable rise time is normally 1/3 of a single dot clock tick, and rise times beyond this result in visible screen image degradation.  Please note: The rise time is over 30% longer than the dot clock tick duration, so a transition from black to white or white to black will be smeared across the next two pixels.

Solution:  
To prevent customers encountering this issue with their display, DIGITAL is encouraging the customers to change the Monitor type in the Windows95 Control Panel.  This will improve the quality of the display and may eliminate the problem with some display monitors, additional changes can be made to the resolution selected.