AP - The Recognized Standard In Audio Test

When AP’s engineers began designing the APx Series, they saw that a new platform was needed to maintain the innovation curve defined by the System One in 1984 and the System Two in 1995.

APx was designed from the ground up with a next generation UI to allow engineers and production testers to get to work quickly and easily. From super-fast measurements to rich graphic reports and sharable project files, everything you need to test audio is available at the click of a mouse.

New measurements have also been introduced to stay ahead of the changing needs of our customers.

No other analyzer in the world is faster or easier to use.

Simple dialogs allow for easy configuration of filters and advanced settings. Repetitive bench tests across multiple signal paths can be automated with the measurement sequencer; level, scope, and FFT signal monitors can be pulled up for real-time analysis. APx can play custom waveforms (square waves, pink noise, etc.) and external source mode allows the testing of playback-only devices such as CD, DVD and MP3 players. Engineers working with power amps can measure continuous maximum output and peak maximum output automatically, view power spectrum graphs with a regulated frequency sweep and take other measurements as specified by the CEA-2006 and CEA-490A standards.

 

Next generation UI

One click measurements & automated sequences

• Use the Measurement Navigator to select a measurement, or select multiple measurements to create an automated sequence.
• AP’s patent-pending “continuous sweep” DSP technique calculates 14 measurements in 7 seconds from a single logarithmic sweep, then graphs results of each measurement for review in the Measurement Selector.
• Define limits or edit settings from their defaults, then click “Start” to run the tests.
• Analyze the results on screen: Select different views, change units, zoom in, adjust limits or cut and paste data into other applications.
• Measure Level, SNR, THD+N, Frequency Response, Burst, Phase, Distortion, Noise, Crosstalk, Phase, all with a mouse click.

Multichannel, real time signal monitors

• Use the Measurement Navigator to select a measurement, or select multiple measurements to create an automated sequence.
• FFT spectrum view up to one million points
• Real-time oscilloscope view
• Level, THD+N and frequency meter readings
• Monitors update continuously even while the APx performs other measurements
• Undock monitor, zoom, copy to clipboard, change units, all in real-time

Saveable, shareable Projects

• Save sequences, settings, limits, and signal paths in one project file.
• Guarantees the exact same test setup on all APx instruments so you can recreate test environments for any engineering or production group anywhere in the world.

Integrated reports for sharing results

• Automatically generate easy-to-understand reports displaying measurements, limit pass/fail, and test setup in rich color graphs and data tables.
• Customize reports with your logo and save as PDF for easy emailing or HTML, Excel, Rich Text Format and plain text for further analysis.

Multiple channel configurations

• 2, 4, 8 or 16 input channels and 2 or 8 output channels depending on your needs.
• Upgrade from 2 to 4 or 8 to 16 anytime.
• Measure across all channels simultaneously for faster, more accurate measurements than using a switcher.

Programming API

• Comprehensive control via API
• Control external instruments from within API
• Library of sample code for .NET, C# and LabVIEW.

New measurements 

Digital Error Measurements

Any device that just passes through digital streams (bitstream mode) strives to be bit-accurate. However, mistakes can happen. Devices may unintentionally truncate data, introduce dither, scale the signal, or convert the sample rate. These errors may be hard to detect with a traditional THD+N measurement, but they can cause havoc for devices receiving the corrupted data later in the signal path.

APx’s bittest calculates the Digital Error rate by taking a pseudo-random waveform with values uniformly distributed between plus and minus full scale and performing a bit-for-bit comparison between the data received from the device under test and the original file. A device passing the data correctly will have a 0% error rate.

The digital data analyzer in 2700 Series and ATS-2 have both provided similar functionality for years. However, one key innovation of the APx Digital Error Rate measurement is the ability to test the encoded audio streams typical in multichannel audio.

The APx’s technique allows both lossless and (through some clever signal manipulation) lossy streams to be tested, crucial for evaluating whether an HDMI source can truly handle all the different formats that may be requested by an HDMI sink.

Fig 1: Average error rate of a device unintentionally truncating the last four bits of a 24-bit word.