Cd Tracking Error
Contents |
electrical signal. If a coherent monochromatic light beam is bounced off the silvered surface of the disc, and the height of the bumps is equal
Tracking Error In Excel
to one quarter the wavelength of the light, the intensity of the annualized tracking error reflected light will fall to near zero when the beam traverses a bump. This is because the light reflected from tracking error control systems each side of the track is delayed 180 degrees in phase, and cancellation occurs. The light source actually used is a compact solid-state laser diode, with a power of about 5
Tracking Error Interpretation
milliwatts and a wavelength of 780 nanometres (nm) in air. The height of the bumps on the disc is 110 nm, which is about one quarter wavelength in the transparent polycarbonate coating. The laser light is in the infra-red band, making it invisible to the human eye, which responds from 430 nm to 700 nm. It has an activating region made of AlGaAs (Aluminium
Tracking Error Etf
Gallium Arsenic) sandwiched between layers of refracting material, forming a light resonator. A photo-diode near the laser diode monitors its output power and compensates for temperature. The beam reflected from the disc is detected by an array of photo-diodes, which drive the player's electronics. In between the laser and the photo-diodes, the light beam follows a tortuous path through an opto-mechanical system that focusses the beam and keeps it following the track as it whizzes by on the disc. At the outside surface of the disc, the beam is about 0.8 mm in diameter, which means imperfections of particles on the surface must be 0.5 mm or more is size to seriously disturb the beam and defeat the error correction systems. The beam must travel through 1.2 mm of polycarbonate, which has a refractive index of 1.55, and focus as a round spot only 1.7 micrometers (um) in diameter at the reflective signal surface. The beam must remain focussed and move less than 1.0 um horizontally and vertically away from the track, even though the CD specification allows a vertical disc warp of 1.2 mm. One of the few thi
For contact info, please see the Sci.Electronics.Repair FAQ Email Links Page. Reproduction of this document in whole or in part is permitted if both of the following conditions are satisfied: This notice is included in its entirety at the beginning. There ex ante tracking error is no charge except to cover the costs of copying. Table of Contents Preface
Tracking Error Formula
Author and Copyright DISCLAIMER Introduction Compact discs and the digital audio revolution Scope of this document Types of problems found in CD players tracking error calculation example Repair or replace? CD Digital Audio Technology General Introduction to CD Technology CD information storage and playback CD (disc) construction CD (disc) manufacturing And you thought driving on a narrow winding country road was tough! Why does focus http://home.mira.net/~gnb/mac-cdis/cd5.html need to be so precise? CD optical pickup operating principles Optical pickup complexity For more information on CD technology CD Player Placement, Preventive Maintenance, and CD Care General CD player placement considerations Preventive maintenance CD lens cleaning discs CD protection and handling CD cleaning Should I really worry about cleaning my CDs? Can a dirty CD or dirty lens damage my player? Rental or library CD considerations Can a CD player damage CDs? Repairing a http://www.repairfaq.org/sam/cdfaq.htm scratched CD Repairing top-side problems on CDs Air purifiers and rubber parts CD Player and CDROM Drive Troubleshooting SAFETY Troubleshooting tips Test equipment Test CDs Useful ways to mangle CDs Getting inside a CD player or CDROM drive CD enhancers What about DVD player and DVDROM drive servicing? CD Player and CDROM Drive Fundamentals Parts of a CD player or CDROM drive Power supply Electronics board The optical deck Typical optical decks Components of the optical pickup Comparison of semi-antique and modern optical pickups Classification of CD player problems Most common CD player problems Troubleshooting Guide Instant troubleshooting chart - most common problems and likely causes General inspection, cleaning, and lubrication Notes on DVD problems Cleaning the inside of the optical pickup Lubrication of CD players Portable DVD players with display General System Problems CD player is totally dead CD player is operational but there is no display or partial display CD player ignores you Drawer does not open or close Drawer operation is erratic Drawer does not close (or open) completely CD changer jams when selecting or ejecting CDs CD player or CDROM drive damages CDs Spindle table loose or sticks to clamper upon eject Intermittent or erratic operation CD player or CDROM drive overheats Operation is poor or erratic when cold Startup Problems What is a startup problem? Startup sequence Procedure fo
which tracks the concentric circular lines of pits. The pits are 0.8 to 3 micrometers long and the rows are separated by 1.6 micrometers. Scaled disc details IndexCD conceptsSound reproduction conceptsReferenceRossingPhysics Teacher, Dec. 87 http://hyperphysics.phy-astr.gsu.edu/hbase/audio/cdplay3.html HyperPhysics***** Sound R Nave Go Back Compact Disc Drive Details In a compact disc player, a http://forum.my.nero.com/index.php?showtopic=8605 laser beam must track a spiral row of pits which are 0.5 micrometers wide with track spacing 1.6 micrometers. Tracking is aided by a three-beam laser arrangement. In addition to staying on the track, which is much narrower than the 100 micrometer groove separation on a vinyl record, the rotation speed must be adjusted as the beam tracks inward or outward. A linear speed tracking error of 1.25 m/s is maintained by increasing the rotation speed from 3.5 to 8 revolutions per second as the beam tracks inward toward the center of the disc. IndexCD conceptsSound reproduction conceptsReferenceRossingPhysics Teacher, Dec. 87 HyperPhysics***** Sound R Nave Go Back Laser Tracking on the CD The laser beam in the compact disc player must precisely track a row of pits which encode the binary data on the disc. In the "three-beam" system, a grating is used to produce tracking error in the first order diffraction maximum to each side of the main beam. Those diffracted beams overlap the track, and the reflected light from the two side beams should be equal, on the average, if the main beam is centered on the track. If they are unequal, then their difference can be used to generate an error voltage to correct the tracking. The illustration of the side beam positions is not to scale; they deviate about 20 micrometers from the main beam. IndexCD conceptsSound reproduction conceptsReferenceRossingPhysics Teacher, Dec. 87 HyperPhysics***** Sound R Nave Go Back Scaled Views of a Compact Disc Data on a compact disc is stored in the form of pits in the plastic substrate. A reflective layer of aluminium is applied to reflect the laser beam. A protective coating is then applied to the top. The laser system reads the data from below. Handling of dust particles and scratches IndexCD conceptsSound reproduction conceptsReferenceRossingPhysics Teacher, Dec. 87 HyperPhysics***** Sound R Nave Go Back Detection of CD Pits The tracking laser beam sees the pits as raised areas which are about a quarter-wavelength high for the laser light. The reflected light from the pit is then 180° out of phase with the reflection from the flat area, so the reflected light intensity drops as the beam moves over a pit. The threshold of the photodiode detector can be adjusted to switch on this light level chan
ROM Focus or tracking error - Could not perform end of Disc-at-once -Errors Alan555 View Member Profile Feb 9 2011, 05:36 AM Post #1 Newbie Group: Members Posts: 2 Joined: 9-February 11 Member No.: 8,894,999 Hello, thanks for the attention, here's my problem:I tried to make an backup of an game that I bought, I created a iso image and tried to burn but the errors that are below in the log that I posted hapened,I lost 3 DVD , 2 trying to burn the iso and 1 trying to burn the iso in .rar file divided in 8 parts , I burned others iso files some days ago without problem, This can be a problem in DVD-Rom?-Because some months ago the DVD-Rom was not reading or burning anything so my brother cleaned the inside of DVD-Rom and he began to run smoothly, here's the log:Windows XP 5.1IA32WinAspi: -NT-SPTI usedNero Version: 8.1.1.0Internal Version: 8, 1, 1, 0Recorder: