Output Board for Dolby E® Audio

  • Provides encoding for up to 8 separate NEXUS signals into a Dolby E® data stream plus a stereo linear-audio downmix
  • Configurable gain (+20 dB), delay (0 to 255 ms), and phase adjustment for all signals coming from the NEXUS
  • Outputs the encoded signal to the NEXUS or from on-board AES/EBU (15-pin D-sub, male) and optical ports (TOSLINK)
  • Video-sync input (BNC) for bi-level and tri-level sync signals
  • Local generator producing an audio clock in sync with the video (i.e. to synchronise the NEXUS to the video-sync signal)
  •  Reads external metadata using the optional XDEM module
  • Generates metadata locally or applies existing metadata from a variety of sources
  • Direct connectivity to an SDI board plus cascading of 2 XDEE boards (option)
  • Sample-rate converters on all audio channels
  • External ports and XDEM metadata input with galvanic isolation

Dolby and the double-D symbol are registered trademarks of Dolby Laboratories.

 data sheet (155 kb)

The XDEE (NEXUS Dolby E® Encoder) is a plug-in board for encoding Dolby E® signals on NEXUS systems. The board comprises a base plate and a module slot which is equipped with an original Dolby OEM module. This makes it possible to generate an individual data stream containing Dolby E® encoded audio.
An additional audio path for an un-encoded audio signal can be used to carry either an independent stereo signal or, for example a commentary channel.

Outputs

The XDEE’s physical ports provide maximum flexibility, rendering extra aux­il­ia­ry converters unnecessary in most cases. The output signals can be made available at three different ports:

  • To the NEXUS bus.  Since the NEXUS is certified for transparent rout­ing of Dolby E® signals, a Dolby E® encoded signal can be trans­mitted and routed at will over the NEXUS network.
  • To AES/EBU (or S/PDIF) outputs on the XDEE.  The XDEE includ­es physical output ports for the coded signals. They are avail­able both from AES/EBU ports and from a TOSLINK optical port simultaneously. Both outputs are equipped with sample rate con­verters and can thus cater for asynchronous signals.
  • To a direct link on an XHDI SDI board.  The XDEE incorporates two proprietary ports which enable signals to be received and forwarded directly from an SDI board without using the NEXUS bus. One SDI board connects to up to two XDEE boards at the same time.

Video Sync

In addition to the outputs for Dolby E® encoded and non-encoded audio, the XDEE features a video-sync input required for encoding Dolby E® sig­nals. The sync signal can be fed to an on-board BNC port or received from the SDI signal if connected directly to an SDI board. The XDEE also in­cor­po­rates an internal video-sync generator which makes it possible to generate a Dolby E® data stream without an external sync signal.
Video-sync signals can be delayed or shifted in order to compensate for la­ten­cies. Thus for example, an early sync signal can be generated to com­pen­sate for SDI-embedder latency.
An audio-clock generator is also included on the board. This gen­er­ates an audio clock signal synchronous with the video-sync signal from the BNC port. This clock can then be used to synchronize the entire NEXUS system.

Metadata

Embedded metadata is characteristic of Dolby E® encoded audio streams. The metadata describes the encoded signal and can be used to control the decoding process. This metadata can be embedded into a Dolby E® stream by sending it to the XDEE as a NEXUS XTI signal. All metadata which is not created within the NEXUS system can be input via an XTI board. The procedure for routing metadata as XTI signals makes it pos­si­ble to receive them from XDED Dolby decoder boards or the XHDI SDI meta­data embedder.
Alternatively, the XDEE can receive metadata in RS422 or RS232 for­mats directly using the optional XDEM module. This module in­cor­po­rates 9-pin D-Sub ports with Dolby-compliant pin-outs.
Metadata is set and managed using the control software.
Within the NEXUS, the metadata embedded into the Dolby E® bit stream can be transparently forwarded, routed with the signal or separate from it. It can, of course, also be edited as required and be displayed for verification purposes.

Delay and Gain

The XDEE cards also feature delay and gain control of the output signals. For example, when the audio is used for sound reinforcement, the vol­ume balance between the various surround signals can be adapted to suit the prevailing conditions. An even more critical factor is the abil­i­ty to compensate for a video-audio offset directly using the Dolby E® board’s delay function. Video-delay functionality is also provided by the new generation of SDI boards.

Applications

The XDEE Dolby E® board is of particular significance in large outside broad­cast units and of course in tv production studios and central control rooms. In fact anywhere where surround transmissions are be­com­ing the standard.

XDEM Metadata Module

The XDEM is an optional module for use as an input board for making ex­ter­nal metadata available to an XDEE board. The Dolby encoder board re­ceives metadata in RS422 or RS232 formats and embeds them. The type of external signal and the pin-out are jumper-configurable. 9-pin D-Sub female ports are used for signal connections.
The XDEE requires only one of the two XDEM ports for applying the data — the second one can be used for supplying a second XDEE.
The XDEM connects to the XDEE using a short ribbon cable. The ex­ter­nal ports are galvanically isolated using a DC-DC converter.

XDEE Specifications

Encoder data format Dolby E® : 16-bit or 20-bit
SMPTE 337M compliant container format of the encoded data stream
NEXUS audio data 24-bit
AES/EBU outputs AES 3, IEC 958, S/PDIF compliant format
Balanced, galvanically isolated output ports
Ports: D-Sub, 15-pin, male
Impedance: 75, 110 ohm
Output voltage: 2…5 Vpp (RL=110 ohm);
                               1 Vpp (RL=75 ohm)
Maximum cable length: 100 m (for lines with appropriate impedance and termination)
TOSLINK outputs
S/PDIF-compliant format
Wavelength: 650 nm
Optical power: –21…–15 dBm (APF 970/1000 µm)
Cable length: 0.2…–15 dBm (APF 970/1000 µm)
Sample-rate converter
Resolution: 24-bit
Up/down sampling ratio: 1:8 (up), 7:1 (down)
Latency: typ. 1 ms, max. 2 ms (@ 48 KHz)
Dynamic range: 140dB(A), min. 132dB(A) @ –60 dBu input level (typ.)
THD+N: typ. –120 dB, min. 117 dB (between 20 Hz and FSOUT and at 0 dBFS)
Pass band ripple: max. ±0.016 dB (0.4535 FSOUT max.)
Stop band attenuation: typ. –120 dB (0.5465 FSOUT min.)
Sync input
Supported video formats:
• NTSC: 525i, 59.94/60; 525p, 59.94/60
• PAL: 625i, 50; 625p, 50
• HD: 720p, 50…60; 1035i, 59.94/60; 1080i, 50…60; 1080p, 23.98…60
Frame rates: 23.975…60 fps
Ports: BNC
Impedance: 100 Kohm / 75 ohm (adjustable using a jumper)
Input voltage: 0.5…2 Vpp on RL = 75 ohm
Sample rates
NEXUS: 44.1 KHz, 48 KHz
Dolby E output: 48/1.001, 48 KHz