AP - The Recognized Standard In Audio Test

The APx is capable of taking 14 measurements in as fast as 7 seconds, automatically generating a report of results and saving all test settings in a single, sharable project file. Real-time signal monitors include residual THD+N in oscilloscope view and a one million point FFT.

With the APx HDMI option, engineers can now use the same tools to measure HDMI audio quality and audio format compatibility on devices such as surround sound receivers, set-top boxes, HD TVs, and DVD & Blu-ray Disc™ players.

The APx HDMI option provides connections for source and sink devices as well as an auxiliary video input and a monitor output. On the input (HDMI Sink) the APx will accept an HDMI signal and analyze the audio content. All standard audio measurements are available including level, SNR, distortion, phase, crosstalk, group delay and others.

Verifying Dolby & dts encoded audio

In addition to generating linear / PCM audio streams, APx can stream lossless formats (such dts-HD Master Audio™) and compressed formats (such as Dolby Digital™ and dts Digital Surround™) from pre-encoded audio test files.

This feature makes it easy to troubleshoot component compatibility and downsampling / downmixing / transcoding issues.

Streaming of .wav, .ac3, .dts, and .cpt over the SPDIF, TOSLINK, and AES/EBU digital outputs is also supported.

Blu-ray audio test

Because Blu-ray and other disc players cannot accept an incoming audio stream, to test Blu-ray audio, test signals must be played from disc. Every HDMI APx includes a Blu-ray Disc with high-resolution versions of a wide selection of audio test signals in the same compressed formats as the APx generator.

Viewing and editing HDMI E-EDID data

An EDID is a ROM inside a piece of HDMI sink equipment such as a TV that informs the HDMI source of what audio and video formats the sink supports. For audio, that includes the number of channels, types of codecs, and sample rates.

EDID must be set up correctly or the source may send formats that the sink can’t handle. For example, if a sink needs 480p video but a source can deliver 1080p, and the source is responsible for downscaling the video to the 480p. If the sink doesn’t report its capabilities properly, the unit is likely to have interoperability problems.

APx provides the ability to view and save the E-EDID of a device connected to the instrument’s source connector. In addition users can arbitrarily edit the E-EDID that the instrument’s HDMI sink presents to a source device under test.

APx HDMI EDID configuration files
APx with HDMI supports multiple EDID configurations. These .edid files are pre-configured for various audio formats, including encoded audio such as DTS. Requires APx585 with HDMI hardware. Please consult the APx User Manual for more information.

Download EDID configuration files

Fig 1. The APx EDID Editor.

Video and third party support

The APx HDMI option has a basic video generator. The user can generate a single color video test signal and control the resolution (up to 1080p), the color of the image, and the color depth (including deep color).

Use of third party video pattern generators is supported by the “Pass External Video Through” option. When an external video signal is provided, APx combines it with the audio stream from the APx’s generator and outputs a single audio/video stream.

The system also forwards E-EDID and CEC data transparently between the device under test and any device connected to AUX IN.

The APx itself does not analyze video; however, all signals delivered to the sink are mirrored to the AUX OUT monitor connector. This allows the user to send the video signal to an external video analyzer or monitor the signal on a display.