SCHUHFRIED

Qualitt durch Kompetenz

ACCURACY OF TIME MEASUREMENT IN CALIBRATED COMPUTER SYSTEMS
DR.STEFAN CHROUST, DR.GERNOT SCHUHFRIED

22nd FEBRUARY 2007

Dr. Gernot Schuhfried Gesellschaft m.b.H. Hyrtlstrae 45, 2340 Mdling, Austria, Tel. +43/2236/42315-0, Fax: +43/2236/46597 info@schuhfried.at www.schuhfried.at FN 104661p Landesgericht Wr. Neustadt, UID Nr. ATU 19273809 TU

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INTRODUCTION
Even with the most careful programming it is not possible to create a program that measures time with a high degree of precision in any computer configuration. The measurement difference between different configurations can be up to 12 msec or more (Chroust, Schuhfried 2006: Die Genauigkeit der Zeitmessung verschiedener psychologischer Testprogramme [The accuracy of time measurement of different psychological test programs). For more precise measurements it is necessary to calibrate the monitor computer response panel system for each individual configuration. In the forthcoming version of the Vienna Test System (Version 6.46, release date April 2007) a calibration function has been added to the hardware test program. The calibration process takes about a minute; an optical sensor, which is connected to the response panel, checks the systems handling of time and makes adjustments if any deviations are found. This calibration should be carried out when the Vienna Test System is installed and whenever the configuration is changed (e.g., when additional programs are installed, even if these programs are not active during a test session). This study aims to evaluate the effectiveness of this calibration function. As in earlier studies, an electronic respondent is used. The start of the stimulus is detected by means of a very fast and highly sensitive photo diode. The signal is amplified and transformed into a digital signal using a threshold value detector. This triggers a highly precise delay circuit, which after a pre-set interval closes a circuit, causing a button to be depressed. The variation in the measurement results of such a calibrated setup is in the range -2 to +3msec. In percentage terms this amounts to a fluctuation of just under +/-1. Such systems measure with a high degree of precision. The remaining measurement inaccuracy results from stochastic errors in the running of Windows programs, for which it is not possible to compensate.
Initial trials with Windows Vista lead one to fear that Vista gives rise to significantly higher measurement inaccuracies than Windows XP.

Stefan Chroust

PRODUCT A: RT-S9 (VTS VERS.: 6.36.0.0) PRTARGET = 33
The electronic respondent was set to have a reaction time of precisely 244 msec. According to the norm score table, this corresponds to a percentile rank of 33.
Table 1: Measured reaction time at a delay of 244 msec, (percentile rank 33) System PC Monitor
1 Desktop PC 800MHz 128MBRam WinXP 2 Desktop PC 1500MHz 512 MBRam WinDesktop PC 2400MHz 512MB Ram WinXP 4 Desktop PC 800MHz 128MB Ram WinXP 5 Desktop PC 800MHz 480MB Ram WinXP 6 IBM Thinkpad R51 Laptop 1500Mz 512 MB Ram WinXP 7 Acer Travelmate 517TE Laptop 366MHz 64MBRam WinAcer Travelmate 722TX Laptop 500MHz 64MBRam WinAcer Travelmate 525TX Laptop 700MHz 128MBRam Win Millenium 10 IBM Thinkpad 600E Laptop 500MHz 64MBRam WinIBM Thinkpad 600 Laptop 500MHz 160MBRam Win98

Sony 446XS CRT 85Hz 1280x1024 Nokia 920C CRT 85Hz 1024x768 Samsung SyncMaster 192v 70Hz 1280x1024 Samsung SyncMaster 192v 70Hz 1280x1024 Samsung SyncMaster 193P 75Hz 1280x1024 TFT 60Hz 1400x1500 TFT 60Hz 1024x768

Measured PR value 34 33

TFT 60Hz 1024x768 TFT 60Hz 1024x768

246 244

TFT 60Hz 1024x768 TFT 60Hz 800x600

243 243

Depending on the computer configuration used, the reaction times reported by the test program range between 243 and 246 msec; the percentile ranks obtained are between PR = 32 and PR = 34. The difference between the measured and the set time is in the range -1 / +2msec. The reaction times quoted represent the mean of the measured reaction times from 28 items. The individual measurements vary in an equally distributed manner by +/- half of the reciprocal screen refresh rate.

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22. February 2007
PRODUCT A: RT-S9 (VTS VERS.: 6.36.0.0) PRTARGET = 20
The electronic respondent was set to have a reaction time of precisely 268 msec. According to the norm score table, this corresponds to a percentile rank of 20.
Table 2: Measured reaction time at a delay of 268 msec, (percentile rank 20) System PC Monitor
1 Desktop PC 800MHz 128MBRam WinXP 2 Desktop PC 1500MHz 512 MBRam WinDesktop PC 2400MHz 512MB Ram WinXP 4 Desktop PC 800MHz 128MBRam WinXP 5 Desktop PC 2800MHz 480MB Ram WinXP 6 IBM Thinkpad R51 Laptop 1500Mz 512 MB Ram WinXP 7 Acer Travelmate 517TE Laptop 366MHz 64MBRam WinAcer Travelmate 722TX Laptop 500MHz 64MBRam WinAcer Travelmate 525TX Laptop 700MHz 128MBRam Win Millenium 10 IBM Thinkpad 600E Laptop 500MHz 64MBRam WinIBM Thinkpad 600 Laptop 500MHz 160MBRam Win98

Measured PR value 21 21

268 267

269 271

269 269
Depending on the computer configuration used, the reaction times reported by the test program range between 266 and 271 msec; the percentile ranks obtained are between PR = 19 and PR = 21. The difference between the measured and the set time is in the range -2 / +3msec. The reaction times quoted represent the mean of the measured reaction times from 28 items. The individual measurements vary in an equally distributed manner by +/- half of the reciprocal screen refresh rate.

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PRODUCT A: RT-S9 (VTS VERS.: 6.36.0.0) PRTARGET = 16
The electronic respondent was set to have a reaction time of precisely 285 msec. According to the norm score table, this corresponds to a percentile rank of 16.

Table 3: Measured reaction time at a delay of 285 msec, (percentile rank 16) System PC Monitor
1 Desktop PC 800MHz 128MBRam WinXP 2 Desktop PC 1500MHz 512 MBRam WinDesktop PC 2400MHz 512MBRam WinXP 4 Desktop PC 800MHz 128MBRam WinXP 5 Desktop PC 2800MHz 480MB Ram WinXP 6 IBM Thinkpad R51 Laptop 1500Mz 512 MBRam WinXP 7 Acer Travelmate 517TE Laptop 366MHz 64MBRam WinAcer Travelmate 722TX Laptop 500MHz 64MBRam WinAcer Travelmate 525TX Laptop 700MHz 128MBRam Win Millenium 10 IBM Thinkpad 600E Laptop 500MHz 64MBRam WinIBM Thinkpad 600 Laptop 500MHz 160MBRam Win98

Measured PR value 16 17

285 287

284 287

284 286
Depending on the computer configuration used, the reaction times reported by the test program range between 284 and 287 msec; the percentile ranks obtained are between PR = 16 and PR = 17. The difference between the measured and the set time is in the range -1 / +2msec.<0} The reaction times quoted represent the mean of the measured reaction times from 28 items. The individual measurements vary in an equally distributed manner by +/- half of the reciprocal screen refresh rate.

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UpgradeAdvisor.com
The first thing you will notice when you unpack the LG Flatron L1980Q is it's quality finish. The base is a shiny chrome color. The display casing is smooth and clean looking. The next thing you will notice is the 8ms response time. This 19" feature packed display is a little more expensive such as the Samsung 193p we reviewed a while back. Even more with the LG L1980Q, it's worth every penny!! The L1980Q features excellent viewing angles, giving you a clear picture as you work or have others looking over your shoulder watching you play (or work.). The 8ms response time and incorporated image enhancement chip make this LCD one of the best in the market for gaming, multimedia use, and plain old web browsing and office use. AutoPivot and AutoMirror functions allow you to swivel and pivot the display if you like to change things up a bit when reading long documents or have a reason to quickly tilt the display backwards to show a presentation.
Click on picture to enlarge image
The brightness and image quality of this LCD is amazing. LG recently developed a feature called the f_engine and the industry's FIRST Picture-Quality Enhancement Chip. The "f"in FLATRON f-Engine represents "fine", as well as fine color, fine image, and fine view, thus implementing a greatly enhanced picture quality. The electronics giant uses DAFI (Digital Adaptive Fine Image) technology in the FLATRON f-Engine, which does not affect color, but enhances brightness and contrast. Initially undertaken last year, the company has just recently completed the development of the technology. The DAFI technology includes a RCM (Real Color Management) function to express vivid natural colors, an ACE (Adaptive Color and Contrast Enhancement) function to enhance brightness and contrast, and enables dynamic mobile imaging. The technology is ideal for mobile imaging in TV, film, mobile games, and animation.

Specifications

Model Display Type Pixel Pitch Max Color Display Size Viewing Angle Resolutions Supported Recommended Resolution Response Time
Flatron L1980Q Color Active Matrix TFT LCD Screen 0.294mm x 0.294mm Pixel 16.2 Million (6 Bits + FRC) 19" Horizontal: 160 , Vertical: x 350 up to 70Hz, 640 x 480 up to 75Hz, 720 x 400 up to 70Hz, 800 x 600 up to 75Hz, 832 x 624 up to 75Hz, 1024 x 768 up to 75Hz, 1280 x 1024 up to 75Hz 1280 x 1024 8ms
http://www.upgradeadvisor.com/content/l1980q.aspx (2 of 4)4/6/2005 7:33:07 AM
Contrast Ratio Brightness Panel Surface
500:1 250cd/m2 Hard Coating 3H, Anti-Glare Brightness, Contrast, Gamma, Horizontal/Vertical Position, Clock, Phase, OSD Position, f-Engine(Preset modes), Color Temp (9300K, 6500K, User), Language, Factory Reset, ADC Calibration, Auto Input Analog RGB 15-Pin D-SUB and DVI-D Horizontal: 30-83kHz Vertical: 56-75Hz 16.6" x 10.3" x 16.1" (WxDxH)

User Controls

Input Video Signal Signal Cable Frequency Dimensions Adding It All Up
I thought the Samsung SyncMaster 193p was going to be the best quality LCD I would ever see. The LG L1980Q not only matches that quality, it adds an 8ms response time to it. Making this display the complete package. Sure you can buy a less expensive 19" LCD with a 16, 12, or even a 8ms response time. But you will not find one with as good of looks and quality with the super fast response time this unit has. The only drawback we found, which isn't a big deal, was the vertical adjustment on the stand was limited. If you like your display high, you will have to put it on a monitor stand. With the large 19" viewing area most users will be happy with the height adjustments available. We took the L1980Q with us to game on at PDX LAN in late March. Sitting right next to us we had gamers with Viewsonic and Dell 17", 19", and 20" LCD displays that are popular among gamers. Every person that walked by this LG LCD had to stop and look at it and ask about it. The display catches your eye with the quality finish and excellent picture. The brightness and clarity was unmatched even by the Viewsonic VG710s we took with us. Want to get your gaming rig noticed, put one of these next to it!!! People will stop and might even notice your modded case after drooling over the LG L1980Q 19" LCD. Because of the excellent quality and super-fast 8ms response time, we are awarding the LG Flatron L1980Q LCD the UpgradAdvisor. com Recommended Upgrade seal of approval!!!

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