Configuring AES3 Input Audio

The codec has an IN1/AES3 input on the rear panel of the codec for AES3 (AES/EBU) format audio. This balanced 110 ohm female XLR input can operate effectively over distances of up to 100 meters and accepts both mono and stereo AES3 signals. If your codec supports multiple channels of AES audio use the DB25 EXPANSION AUDIO I/O connection to send/receive up to 4 additional channels of AES3 audio. Please note that expansion inputs/outputs 3, 4, 5 and 6 must be either all analog or all digital AES. See Appendix B for the DB25 wiring pin-outs.

 

1.Press the SETTINGS Settings button button.

2.Navigate to Audio and press Ok button.

3.Select Input Type and press the Ok button button.

4.Navigate to the inputs you want to configure and press the Ok button button to toggle between Analog and AES3.

 

The 3 pin male XLR AES3 OUT connector is capable of sending both mono and stereo AES3 signals.

 

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Important Notes: Input levels are set at 100% automatically for AES3 connections. If you switch back to the analog input setting after selecting AES3, the previous analog settings will be recovered.

 

AES3 Sample Rate Conversion

The codec contains two sample rate converters.

 

Input Sample Rate Converter

The codec implements an Asynchronous Sample Rate Converter (ASRC) to convert the sample rate of an AES3 input to the sample rate set in the codec. The codec sample rate is determined by the selected algorithm.  For example, if you select the Music algorithm, the sample rate will be set to 32kHz.

 

By default the codec will up-sample all channel 1 and 2 AES3 input sources to 96kHz sampling unless your audio source uses a 44.1kHz sample rate.

 

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Important Notes: If your codec supports up to six AES3 inputs, the three AES3 stereo inputs are multiplexed onto analog inputs 1, 3 and 4. There are also three AES3 stereo outputs via the AES3 Out XLR and two are multiplexed onto outputs 3 and 4 (see Appendix B for pin-outs of inputs 3 and 4 and outputs 3 and 4).

 

The inputs have asynchronous sample rate converters to facilitate sources with different sample rates being attached to the codec. For example, IN1-AES (Inputs 1 and 2) can be 48kHz AES-IN2 (IN3&4) can be 32kHz and AES-IN3 (IN5&6) can be 96kHz

 

Output Sample Rate Converter

The sample rate of the AES3 output is configured using the clock source setting via the SETTINGS Settings button button and then Audio > Input Type > AES3 Out. This configures the sample rate frequency of all AES3 output signals and there are three possible settings.

 

AES3 output clock source - Fixed48

 

Locked to AES3 Input

If this setting is used, the codec will use the sync information received by the AES3 input to set the output sample rate in the codec (Note: this is the same as the AES Rx Clock setting in Tieline G3 codecs). The codec will initially try to use the signal on AES inputs 1 and 2 as the clock to which the AES outputs are synchronised. If unavailable, it will then attempt to use inputs 3 and 4 or inputs 5 and 6 in that order. If you select this option, all AES inputs must always be synchronised to the same clock source, e.g. if AES3 inputs 1 and 2 use 48kHz sampling then inputs 3 and 4 and inputs 5 and 6 must also be synchronised to the same clock.

 

Wordclock Sync In

This setting configures the codec for a word clock source via the SYNC INPUT on the codec rear panel  (this is the same as the External Word Clock setting in Tieline G3 codecs). Often this will be a studio reference signal (D.A.R.S., or Digital Audio Reference Signal). In television broadcasting facilities, the audio reference signal should be locked to the video reference if there is one available. The sample rate being received is recognized by the codec and automatically adjusted within it. Sample rates from 32 kHz to 96 kHz are accepted, including the most popular rates of 32 kHz, 44.1 kHz and 48 kHz.

 

Fixed Sample Clock

Select from a range of fixed output sample rates.