Clover QA-101D compact disc analyzer – includes related article

Clover QA-101D compact disc analyzer – includes related article – Evaluation

Robert A. Starrett

It would probably be fair to say that more than a million CD-R discs are produced in this country every day. With more and more discs being burned, more and more of them are going to have some problems.

Generally, the errors that cause problems for compact disc playback–assuming that the drive playing the disc is in good condition–can be classified as physical, logical, and environmental. Logical errors are those errors that have their origin in the structure of the disc. Corrupted data, a corrupted table of contents, improper link blocks, or an improperly finalized disc are all common logical errors. Physical errors relate to something about the physical medium itself, usually pit geometry, that in combination with the playback machine, produce errors that exceed the rates allowable for compact discs in their different formats. Environmental errors are the result of dust, scratches, fingerprints, or foreign substances on the face of the disc.

Such errors are hardly uncommon and are likely to stay with us as long as CDs are produced and used. The good news is that several products, both hardware and software, are available to users for testing for logical and physical errors at the prototype stage and beyond before bad discs become bad business. High-end industrial-strength physical-error testers often cost $20,000 or more, which prices them out of the range of small and midsize publishers and service bureaus.

But fitting perfectly into that ever-growing niche—where quality control requirements are as critical as anywhere–is the Clover Systems QA-101D CD Analyzer, a standalone or PCconnected solution for testing pressed and recorded CDs for physical errors. Versatile and low-priced, the Clover QA- I 01D gives the user quick and detailed error reporting for both CD-R and replicated discs. The built-in disc grading system allows any user to judge the quality of a disc quickly with no technical knowledge of the low-level errors that are being tested. For the professional, the QA-10ID offers lots of detail and many options for advanced testing.

WHAT IT DOES, HOW IT WORKS: QA-101D Q & A

A compact device no bigger than a stereo component, the Clover QA-101D announces its presence with authority with a front panel featuring the disc tray and eject button, the on/off switch, a red LED to indicate an E32 (uncorrectable error) condition, an orange light to indicate a tracking error, and a green light to show that the unit is interfaced serially with the optional QA-Net software. In the center of the front panel is the fluorescent display that shows the error status in many different configurations.

To the right of the display is a twelve-button pad that controls the the contents of the display. Here reside the play, stop, pause, fast forward, fast reverse, next track, and previous track buttons, plus five others that control the error display. The display is flexible, allowing you to see several views of what is going on as the disc is being tested.

Clover’s QA-Net software–version 2.21 is a $495 add-on to the otherwise-standalone tester–installs quickly and easily on your PC and the tester can be connected to a host via a supplied serial cable. QA-Net allows you to see and save the results of testing in a graphical format. The program is simple to use, locating the tester automatically on startup and allowing you to choose the errors that you want graphed. The resulting line graph represents each error with a different colored line, and this makes it easy get a quick overall look at the quality of the disc being tested. The axes of the graph–vertical, charting errors per second, and horizontal, charting time–can be adjusted to various tastes and presentations by clicking on the axis, which brings up a properties dialog box.

Once your testing is complete, you may save the results for later viewing and printing or you can click the print button to produce a hard copy. A color printer is preferable, although you can get by with black and white if you distinguish each error type by changing the line attributes.

The QA-101D also has a printer port on the back of the unit. Hooking up a printer will produce a real-time printout of errors as they are detected and automatically print a summary of the results when testing is finished.

BEYOND THE BLER: ERRORS REVEALED, REPORTED

Block Error Rate (BLER) is the most useful measurement of the overall quality of a compact disc. BLER is a measurement of the number of data blocks per second that return bad symbols (bytes) to the CD decoder. Cross Interleaved Reed Solomon Code (CIRC), the core error correction on compact discs, uses two stages of error correction: C1 and C2. The errors E11, E21, and E31 indicate, respectively, that one, two, or three errors were detected and corrected at the C1 stage. Errors E12 and E22 mean that one or two errors, respectively, were detected and corrected at the C2 stage. An E32 error means that three or more bad symbols (bytes) were presented at the C2 stage and the error thus is uncorrectable.

All this sounds unnecessarily technical at first, but the QA-101D manual provides an excellent discussion of CD errors and their interpretation. And the built-in grading system allows the user to determine the quality of a disc without specific knowledge of the what and why of each error. A disc graded A is a top performer. A disc graded B is an excellent disc, but not perfect. Grades C and D denote usable discs that are more susceptible to failure through scratches, fingerprints, and dust since these increase errors over time and can eventually put the disc over the edge to the F category, which indicates a disc should not be used.

For more sophisticated testing, the QA-101D has connectors on the back that provide buffered HF, TRK, EFM, and AES/EBU outputs for connection to an oscilloscope, spectrum analyzer, jitter analyzer, or other measurement equipment. When connected through the HF output to an oscilloscope, the QA-101D allows you to measure, through an “eye pattern,” Itop, 111, 13, asymmetry, jitter, and reflectivity. Measurements available through the TRK output are push-pull, eccentricity, and radial noise.

TEST WITH THE CLOVER (OVER AND OVER)

The Clover QA-101D is a versatile, valuable, and inexpensive vehicle for companies, large and small, and for flush single users to test the quality of their CD-R output and to test the quality of their replicated discs. The QA-101D is solidly built and self-contained so no computer is required to use it; it can be run by the E-error-illiterate as a standalone system and easily used to grade CDs.

For more intensive testing, tracking, and graphing results, the optional QA-Net software gives an excellent graphical picture of the various physical errors one might encounter on a given disc. For the professional, coupling the QA-101D with an oscilloscope digital preferred allows the testing of many advanced parameters this makes the QA-101D the best value in CD testing equipment with its new $3,333 price.

Given the myriad potential physical errors that routinely befall CD publishers whether producing sizeable runs of pressed CDs or one-off and short-run CD-Rs the Clover QA-101D may prove the only product in your price range equipped to save you from the inevitable embarrassments, returns, and technical support headaches attendant to shipping error-prone CD products.

RELATED ARTICLE: Clever Systems QA-101D Compact Disc Analyzer

Synopsis: The Clover QA-101D is a versatile, valuable, and inexpensive way for companies, large and small, and for affluent single users to test the quality of their CD-R output and to test the quality of their replicated discs. The QA-10ID is solidly built and self-contained so no computer is required to use it; it can be run by the Error-illiterate as a standalone system and easily used to grade CDs. For more intensive testing, tracking, and graphing results, the optional QA-Net software gives an excellent graphical picture of the various errors. For the professional, coupling the QA-101D with an oscilloscope-digital preferred–allows users to test many advanced parameters. This makes the QA-101D the best value in CD testing equipment with its new $3,333 price.

Price: $3,333, including tester plus Philips SBC-44A test disc and qualification discs; QA-Net 2.21, $495 add-on

For more information, contact:

Clover Systems 31642 S. Pacific Coast Highway, Suite 101, Laguna Beach, CA 92677; 714/499-9566; Fax 714/499-4844; http://www.cloversystems.com; INFOLINK #404

RELATED ARTICLE: Can You Afford to Test?

Although the Clover QA-101D is not the only compact disc tester available, it is the most inexpensive. CD Associates still offers its low-end SL-25 tester for a little under $5,000 (www.cdassociates.com). But industrial-strength CD testers can run into the tens of thousands of dollars.

The best strategy for deciding on what equipment is appropriate for your testing needs is to assess those needs carefully. Questions you might ask include:

* What parameters need to be tested?

* What do we want to test in-house and what do we want to send out?

* Will our replicator test each batch of pressed CDs that they

* make and give us a quality report?

* Should we contract for certain standards that each CD must meet?

* Should these standards be more stringent than what the Red Book calls for?

* How high does the quality of our CD-R discs need to be?

* Is it enough that it plays in a drive or two?

The answer to the last question is “probably not.” The answers to the previous questions are just a part of the data you need to make a well-informed decision on whether to test in-house. But with quality machines like the QA- I 01D available for a very reasonable price, you might just ask yourself this question: Can we afford not to test our CDs?

Robert A. Starrett (bobs@cdpage.com) is a contributing editor for EMedia Professional, cocolumnist for THE CD WRITER, and an independent consultant based in Denver, Colorado. He is the co-author of CD-ROM Professional’s CD-Recordable Handbook.

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