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Audio Precision marks 25 years by cracking 1MHz FFT barrier

Marking its 25th anniversary at AES 2009, Audio Precision introduced a new ultra-high-bandwidth analyzer option for the APx525 family of audio analyzers. The new BW52 high-bandwidth option extends its fast Fourier transform capability all the way to 1MHz, with 24-bit amplitude resolution and 2Hz frequency resolution, making APx the ideal tool for designers of Class D amplifiers, sigma-delta converters and other modern audio devices.

Director of marketing Tom Williams, demonstrating the new unit on the show floor, said, “Working with modern designs like Class D amps, you are dealing with issues like switching frequencies that occur far beyond the range of normal analyzers. With the BW52, you can see those issues at a glance.” Prior to the BW52, design engineers have had to use lower-resolution equipment like oscilloscopes and spectrum analyzers to “see” noise and hum beyond 100kHz, which lack the clarity of resolution and ability to tolerate high input levels that an audio analyzer provides.

“Twenty years ago, these higher frequencies didn’t affect audio design,” Williams said. “But with Class D amps and similar devices, design artifacts in the 300MHz to 500MHz region are normal. Identifying and controlling them is of critical concern to equipment manufacturers.”

The new BG52 hardware will ship in January 2010 and will be available on Audio Precision’s 525 Series of analyzers, either as an upgrade package or as part of a new unit.

For broadcasters, Audio Precision is offering High Speed Tester, a free software package that broadcasters can use to measure QoS for audio delivery in the field. The program uses a five-tone burst to measure audio quality, and then e-mails a report to the broadcaster. The software works in conjunction with an AP analyzer such as the 2722 or ATS2.

“The advantages of these systems are twofold,” Williams said. “First, the burst tone is of very short duration, only a half-second, so it doesn’t disrupt normal programming. In addition, our multitone is designed to eliminate the false positives that can happen with certain types of content, like hard rock or techno music soundtracks.”

With broadcasters now streaming audio via numerous third-party carriers as well as their own transmissions, assuring QoS is more critical than ever. The AP High Speed Tester is already successfully in use out in the field. “In both Canada and France, there are stations set up all over the county with our analyzers installed, just waiting for the multitone to be broadcast. We’ve had no reports of false positives, and these broadcasters now have full confidence that the audio being heard out in the field is the same quality that was sent out,” Williams said.

Williams noted that AP’s origins were in broadcast. “Twenty-five years ago, every single station had a dedicated engineer whose job it was to make sure all the gear was working correctly,” he said. “You could almost guarantee they would have an ATS2 or something equivalent in their tool kit. The same thing holds true today, but obviously the gear is more complex and varied. The nice thing is that you can still use the same technology to troubleshoot your broadcast suite. Audio Precision continues to supply the tools that broadcasters need, while also developing revolutionary tools like the BW52, which will help design engineers create the next generation of audio products.”