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THE CDX | QA-CDX The revolutionary CD analyzer that can fit in any available slot in a PC and performs data verification, format verification and measure error rates. The software can accommodate mulitple 40X CDX drives simultaneously offering very high throughput. It has an HF output so you can make pit geometry measurements using an oscilloscope. Connected to a notebook the CDX is truly portable. |
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THE DVX | DVX™measures DVD error rates at up to 16X on DVD-ROM and DVD±R, including dual layer discs. It can also measure Beta and Jitter, and check the quality of blank media. DVX™ can perform bit-for-bit comparison of two discs of any type, including video, audio, or data. DVX™ can also do bit-for-bit comparison of two discs without access to the original using a new exclusive feature. With an optional Analog Board, it can also make analog (pit geometry) measurements. |
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Autoload This PC-based robot allows DVX to test hundreds of discs unattended. Failed discs are separated from good, and test results are saved to a file. The AutoLoader includes a built-in PC, so the whole system is in one self-contained unit. | |
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NEW AMM-1 |
Analog Measurement Module You can now make analog (pit geometry)
measurements automatically with the new AMM-1 Analog Measurement Module!
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THE DBA | QA-DDB-1 The Dynamic Disc Balance Analyzer is measuring imbalance of DVD & CD discs, conformance to Red/Yellow/Orange book standards can be verified with this system. Disc imbalance can be caused by thickness variation of substrate, lacquer/CD-R dye coating or DVD bonding layer as well as asymmetrical label design, discs can be tested in 10 seconds. |
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Contact Eyecote for further CD-Testing Information European Office: Eyecote International Ltd. Singleton
Court Business Centre, Monmouth. NP25 5JA U.K. USA Office: Eyecote Media Services. 26241
Enterprise Court, Lake Forest, CA 92630 |
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FURTHER REFERENCE |
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ANSWERS TO FREQUENTLY ASKED QUESTIONSWhat are the differences between CDX and QA-101? Why do I get different results on different test systems? Why does this disc work fine on some players, and not others? If a disc tests good, is it sure to play on all players? How repeatable should the test results be? Is BLER the best measure of disc quality? Can I use your equipment to test blank CD-R media? What is the best speed to test at? Is an oscilloscope necessary for thorough testing? What do you use to calibrate the systems? How do you calibrate error rates? What kind of drives do you use? I get a high figure for the E12 peak, even for very good CDs. Is that normal? What kind of printer do I need for my QA-101? Where can I find specifications for CD's and DVD's including physical and logical data formatting? How does the Balance Analyzer work? How do you calculate Moment of Inertia?
Q. Why do I get different results on different test systems? Errors can be caused not only by local defects on the disc, but by the inability of the player to focus, follow the track, or recover the data clock. Small variations in the player servo systems can cause large variations in error rates. In general, discs that meet Red Book specifications will produce repeatable results. Large variations in results are invariably caused by discs that are outside the Red Book specifications. In addition, if one or more parameters are close to the Red Book limits, results can be unpredictable. There is however, a playability test disc (Philips SBC444A) which has a variety of built-in errors. This is a good way to test whether your playback system is working correctly. In many cases, test systems using single-beam players will produce different results that three-beam players because of the difference in ability to track the pits in the presence of various types of defects. Q. Why does this disc work fine on some players, and not others? Q. If a disc tests good, is it sure to play on every player? There are no standards for CD players; only for discs. The way it’s supposed to work is that the players should be able to play any disc that meets Red Book specs. Therefore, if you make the discs to Red Book specs, they should play in all players. To be certain that the discs meet all Red Book specifications, you need to measure at least 50 different parameters - a costly and time-consuming endeavor. Disc manufacturers of course, must do this to ensure compliance with CD Licensing agreements. The more things you can measure, the greater confidence you can have that a disc will play in all players. The key to disc reliability is pit geometry. The player's ability to follow the track and stay in focus depends on the way the laser beam is reflected from the disc. This in turn, is wholly dependent on the size and shape of the pits. The QA-101 and CDX have HF outputs so that you can measure things like I11, I3, Asymmetry, Jitter, and Reflectivity using an Oscilloscope or other test equipment. These are some of the more important signals that show if the pits are properly formed. If these parameters are not well within Red Book specs, the disc cannot be counted on to play reliably in all players. As all parameters approach their allowed limits, the likelihood of playing in all players diminishes. The best strategy is to make sure that all discs are as close to optimum as possible. By looking at the HF signal (“eye pattern”), you can learn to recognize discs that are likely to fail on some players. Q. How repeatable should the test results be? Q. Is BLER the best measure of disc quality? Q. Can I use your equipment to test blank CD-R media? As discussed above, the key to disc quality is good pit geometry, which is dependent on the interaction between the writer and the media. In order to QC incoming media (which is an excellent idea), you will have to record something. At today's prices, it is justifiable to waste one from each batch to see how it works. The media should be pretty consistent within a given batch, so once everything is working properly, you don't have to test every disc. When evaluating media, it is best to record the entire disc, since problems are more prevalent at the outside of the disc (due to manufacturing considerations). Q. What is the best speed to test at? This doesn't necessarily mean that the disc is no good. CD-ROM drives will fall back to a lower speed if the disc is not readable at the current speed. They also use up to 10 re-tries to recover the data. In most applications, the user is completely unaware of this. Generally if the disc performs well at high speed, it is a pretty good bet that it will work at lower speeds, although this is not always the case. Since CD-ROM drives are optimized for higher speeds, drive performance may be compromised at lower speed. Also, results can be affected by vibration, which varies with speed. Q. Is an oscilloscope necessary for thorough testing? The easiest way to measure disc quality is to measure error rates. Most serious problems will affect the error rates. But this only tells you how well this disc plays in ONE player. To have confidence that the disc will work in ALL players, ALL the time, you need to look at the pit geometry. In order to follow the track of pits and stay in focus, the player depends on the way the laser beam is bounced back from the disc. This is totally dependent on the size and shape of the pits. In order to have confidence that all players will play the disc reliably, you need to confirm that the pit geometry is well within Red Book specs. This is where the oscilloscope comes in. Measuring pit geometry is not something you need to do all the time. Most people get away with ignoring it. Where it is really useful is in evaluating CD-R media, writers, and discovering the cause of poor performance. It's a very useful tool to have, but you don't have to use it. Q. What do you use to calibrate the systems? Q. How do you calibrate error rates? This can be done using the two Qualification Discs that come with the QA-101 or CDX. Disc 6E is a “good” disc with low error rates, and SBC444A is a disc with known defects. To confirm that your system is operating properly, test both discs at 1X and compare the results with the test results we have provided. If you don’t get the expected result, you know that something is wrong. Obviously, your results will be affected by dirt, dust, and scratches, so you should be careful to avoid damaging these discs. Testing these discs on a regular basis will provide confidence that your equipment is working properly.When comparing with the factory test results, be sure you use the same speed used in the original test. Disc SBC444A provides two kinds of defects: Missing information, and black spots. The tracks with missing information provide repeatable results since these errors are encoded into the data. The sections with Black Spots have the information intact, but obscured by the black spots. In this case, not only is there information lost, but the servo mechanisms are stressed. For example, when the readout beam encounters the black spot, focus, track following, and clock recovery servo signals disappear. After the beam has passed the black spot and the signal is restored, the pickup is out of focus, off track, and the bit clock is at the wrong frequency. This causes many additional errors to be generated in an unpredictable way. Therefore, the number of E32 and Burst errors generated by the Black Spots in particular may vary. This is because these errors are “soft errors.” That is, they are caused by disturbance to the player’s servo systems, rather than loss of data. Each time the disc is played, the disturbance is slightly different, and the results cannot be predicted. It is not always necessary to test the entire discs. Regular checks of the system can confirm that the system is capable of producing low error rates on a good disc, and can also play a disc with large defects. Q. What kind of drives do you use? Q. I get a high figure for the E12 peak, even for very good CDs. Is
that normal? Therefore, if every byte of the block is bad at C1, it would cause 28 single-byte errors (E12) at the C2 stage. So the E12 error rate can be as much as 28 times as high as E31. In severe cases, some of those errors may then become E22 and E32 as well. Even on the best discs, one usually gets some E31's that then become E12's. The numbers seem large because of the de-interleaving. Unless you know exactly which bits of the block are bad, you cannot predict how much larger E12 will be compared to E31. Peak E12 of up to 500 is common, but as long as they are not E22 it is OK. Typically, this is caused by small local defects on the disc. My experience is that E12 rates tend to be higher on CD-R discs compared to molded discs. Q. What kind of printer do I need for my QA-101? Hewlett-Packard has the best selection of printers that will work with QA-101. Of the current models, the lowest cost HP printer that will work with QA-101 is the Deskjet 3820, which sells for around $99. Most older HP printers will also work. Here is HP’s advice: “All Hewlett-Packard printers that have PostScript printer language
will HP's web site has detailed information on their current printers, and
specify if they accept plain ASCII text. Q. Where can I find specifications for CD's and DVD's including physical
and logical data formatting? www.ansi.org Some of these sites may also refer you to others which offer these documents. The documents are not free, but are usually available at reasonable cost. Q. How does the Balance Analyzer work? Q. How do you calculate Moment of Inertia? I = M/2 · (R1 2 + R22) Where I = Moment of Inertia So, a typical disc with R1 = 7.5 mm (radius of inner hole) and R2 = 60 mm (radius of entire disc), and a weight of 15 grams will have a moment of inertia of 27422 g-mm 2 . The DVD spec uses units of gram - meters2 , so divide by 1,000,000 to get g - m 2 (there are 1,000,000 square millimeters in a square meter). So this disc would have a moment of inertia of 0.027 g-mm 2. If the disc is not perfectly uniform (balanced), then the moment of inertia is increased by M·h 2. M is the weight of the disc, and h is the distance between the geometric center of the disc and the center of mass (which is exactly what the Balance Analyzer measures). Ud as measured by the DBA is Mh, where M is in grams and h is in millimeters. You can find h by dividing Ud by M. Ud = Mh so h = Ud/M So if the unbalance is 10 g-mm, then h = 10 g.mm divided by 15 g = 0.67 mm. So now Mh 2 = 6.7 g.mm2 = 0.0000067 g.m 2. As you can see, an acceptable amount of imbalance adds very little to the Moment of Inertia. Using the maximum allowed weight (20g) and maximum allowed unbalance (10 g-mm), gives a moment of inertia of 0.037 g-m2 , which is less than the allowed 0.040 gm 2 for moment of inertia. |
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