Electronic Design
Audio Analyzer Keeps Contract Manufacturers Honest

Audio Analyzer Keeps Contract Manufacturers Honest

With so much of the production of electronic systems having shifted to China and other areas of Asia, the vertically integrated OEM has become a rare bird indeed. The implications of this shift, which has occurred over the past couple of decades, are myriad and, for the most part, well known. But what are coming to light more these days are the implications that this fundamental change in the OEM business model has for production test.

No one blames the contract manufacturer for doing what it can to make money, but then there are the times when it does so at the expense of product quality. It’s not uncommon for an OEM to test one of the first units off the production line and find that it doesn’t perform as specified. Upon opening up the unit, you might find that the manufacturer has used components of lesser quality. The manufacturer may have even gone so far as to redesign the circuit board to make it less costly to manufacture.

Such situations have resulted in some tension, and even distrust, between the OEM and the contract manufacturer. Despite having a contract with the organization building the OEM’s end product, there’s apt to be some anxiety about whether it is actually building what is has been contracted with to build.

It can be difficult to force a manufacturer not to cut corners on the build of a product. But an approach that has been growing in popularity is to contractually bind the manufacturer to test the product in a specified manner using equipment supplied by the OEM. And this is the thinking behind Audio Precision’s introduction of its APx515, a two-channel audio analyzer (see the figure) intended specifically for production test. The tester, which starts at $6200, still delivers excellent performance with a typical total harmonic distortion plus noise (THD+N) specification of –106 dB, 24-bit fast Fourier transforms (FFTs), and 192 kbits of digital I/O.

According to Dan Knighten, Audio Precision’s vice president of products, there are a couple of scenarios in which OEMs can compel contract manufacturers to test their end products in an acceptable manner. “The contract manufacturer doesn’t do anything they’re not required to do,” says Knighten. “Typically the OEM will specify the tests the manufacturer needs to make, and the manufacturer will make a counter-proposal as to how to accomplish that. In some cases, the OEM buys the analyzers and loans them to the manufacturer. Or, the OEM will specify the analyzers and the manufacturer buys them and charges the cost back to the OEM, amortized into the price of the end product.”

To make the APx515 affordable enough for the production-test market, Audio Precision essentially dialed back the precision that it builds into its flagship 2700 series instruments. “The 2700 series has less than a microvolt of analog noise,” says Knighten. “We cut that back by about 10 dB in the APx515, which is still an order of magnitude better than most other audio analyzers.” The APx515 is also built in an economic, non-modular fashion, which saves cost in terms of internal connectors and multiple discrete printed-circuit boards.

Another advantage of the APx515 in the production environment, and another way in which Audio Precision held down the instrument’s cost is that it uses the same software as the company’s high-end analyzers. It also makes it easy to share test routines with the contract manufacturer for use on the production floor.

“R&D departments here in the West or in China will be likely to have our high-end units,” says Tom Williams, Audio Precision’s vice president of marketing. “They can define the test routine on their units and mail them over to the manufacturer for running on the APx515.”

When performing quality assurance testing on the production line, the APx515 operator can save a recording of the actual output of a device under test and e-mail it (along with the 515’s settings) back to the R&D team for further analysis.

The APx515 costs $6200 in the U.S. Prices may vary outside the U.S. The High Speed Test, Advanced Engineering Measurements and Acoustic Response software options cost $500, $750, and $150 respectively or bundled together for $1000. The first unit will ship in August.

Audio Precision
http://ap.com

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