Quantum Data 881 User Manual
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881/882 Video Test Generator User Guide (Rev A.22)
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Testing multi-channel compressed HDMI audio formats
The 882E instrument enables you to test HDMI compressed audio formats such as AC3,
EAC3 and the HDMI 1.3 high bit rate lossless compressed audio such as Dolby TrueHD
format. TrueHD's may carry up to 8 discrete audio channels, at a sample depth & rate of
24-bit/96 kHz (Blu-Ray Disc format specification allows also for encoding up to 6 channels
at 192 kHz).
Multiple scenarios are provided that allow you to test all audio channels at different
amplitudes and frequencies, as well as test using the different supported sampling rates.
The sampling rate for all channels is completed through a single image (AudioRAT).
High audio sampling rates and channel counts may require additional bandwidth in the
blanking intervals. The required additional blanking intervals may only be available with
high definition formats for example 720p and 1080i. When outputting 8 channels, the
audio sampling rate is only guaranteed to 96kHz and requires that you use a high
definition format.
Only two channels are guaranteed at the 192kHz sampling rate. These two channels must
be from the generator’s internal sine wave generator as the SPDIF input is only
guaranteed to 96kHz.
Note: Unlike the uncompressed formats (linear PCM) the compressed audio test signals
are generated from a file. As a result the amplitude and frequency cannot be adjusted
through the audio test images.
To test compressed audio formats on an HDMI device from the generator:
1. Set up the generator for HDMI output. See “
Setting up the generator for HDMI testing
2. Press the
Source key and select the first test format (for example: 720p60).
Alternatively, to select the format using the command line interface, enter the following
commands:
/tffs0/Library/Formats // Set format path to generator memory
720p60
// Loads the 720p60 format
// Activates the 720p60 format