Murraypro Introduces New Analysis Features For Test Chest

In response to user's requests for this utility, Murraypro will unveil new Test Chest analysis capabilities at IBC in Hall 8, by introducing an AES Eye feature for the first time.

Following on from the success of the SDI Eye display, Test Chest's new AES mode now includes a discrete Eye display. This is a really useful facility, using the wide bandwidth analogue waveform mode to facilitate engineering evaluation of the performance of AES cabling and distribution infrastructure.

Users will be aware that whilst historically the discrete AES bitstream has been distributed via XLR-3 as a balanced signal on twin screened cable at 110 ohm impedance, with a tendency more latterly to use BNCs on coaxial cable at 75 ohms, the balanced signal amplitude is likely to be around RS422 distribution levels, i.e. 3 V/leg, and a nominal 1 V when in unbalanced format.

These two differing distribution systems have widely varying matching requirements and, in purely engineering terms, it is simply not practical to just use a "straight through" BNC/XLR converter for interconnection purposes.

Test Chest's Audio Pod comes to the rescue as it already provides an extremely useful AES matching transformer with both XLR and BNC connectors. Cunningly it also integrates a matching embedded 10 dB attenuator, to reduce converted unbalanced signal levels to around 1V, preventing overload, whilst enabling optimum matching to the network under evaluation. The transformer also ensures vital high voltage Galvanic isolation between the interfaces.

Low jitter processing was always a vital design goal for the AES Eye mode, and one which has been very successfully achieved. The non-scrambled AES data is cleanly decoded from the bi-phase mark bitstream, and the AES run-in and run out pulse trains are clearly visible in the 'Word-rate' timebase in the photo above.

So there you have it, Test Chest's LCD display may be used to assess incoming system jitter directly in one elegant battery powered, and highly portable device. The best part however is yet to come – all this additional functionality is provided with no increase in the cost of Test Chest; and existing Users of the "Test Chest – HDVI" model will be able to upgrade their Units to include this new feature immediately after IBC.

Full details and continuous demonstrations will be available at the Murraypro IBC Stand B.38 in Hall 8, or visit www.murraypro.com, or email [email protected].

This article is also available to read in the August edition of Broadcast Film & Video.