Steinberger Nuendo DD8 User's Manual

Nuendo DD8

Operation Manual

Benutzerhandbuch

Mode d’emploi

Table of Contents

1. Introduction........................................................................................................5

2. Package Contents.............................................................................................5

3. Brief Description and Characteristics.........................................................5

4. Technical Specifications.................................................................................7

5. First Usage – Quick Start..............................................................................10

6. The AES to ADAT/TDIF Converter.............................................................13

7. The ADAT/TDIF to AES/EBU Converter...................................................19

8. Clock Section...................................................................................................25

9. Word Clock.......................................................................................................30

10. Conversion Modes and Notes.................................................................34

11. Technical Background...............................................................................38

12. Controls and Connectors..........................................................................42

13. Connector Pinouts.......................................................................................43

14. Block Diagram...............................................................................................44

15. Warranty..........................................................................................................45

16. Appendix........................................................................................................45

NUENDO DD 8

Inhaltsverzeichnis

1. Einleitung..........................................................................................................47

2. Lieferumfang....................................................................................................47

3. Kurzbeschreibung und Eigenschaften....................................................47

4. Technische Merkmale...................................................................................49

5. Inbetriebnahme - Schnellstart...................................................................52

6. Der AES zu ADAT/TDIF Konverter.............................................................55

7. Der ADAT/TDIF zu AES/EBU Konverter...................................................62

8. Clock Sektion....................................................................................................68

9. Wordclock..........................................................................................................73

10. Betriebsarten und Anwendungshinweise..........................................77

11. Technischer Hintergund............................................................................81

12. Bedienungselemente und Anschlüsse.................................................85

13. Steckerbelegungen.....................................................................................86

14. Blockschaltbild..............................................................................................87

15. Garantie...........................................................................................................88

16. Anhang............................................................................................................88

ENGLISH DEUTSCH FRANÇAIS

NUENDO DD 8

iii

Table de Matières

1. Introduction.....................................................................................................91

2. Contenu du produit......................................................................................91

3. Description rapide et Caractéristiques...................................................91

4. Caractéristiques Techniques......................................................................93

5. Première Utilisation – Démarrage rapide..............................................96

6. Le Convertisseur AES vers ADAT/TDIF....................................................99

7. Le convertisseur ADAT/TDIF vers AES/EBU.........................................106

7.4 Sorties AES/EBU..........................................................................................109

8. Section Horloge............................................................................................112

9. Word Clock.....................................................................................................118

10. Modes de Conversion et Notes.............................................................122

11. Eléments Techniques...............................................................................126

12. Contrôles et Connecteurs.......................................................................131

13. Brochage des Connecteurs....................................................................132

14. Schéma..........................................................................................................133

15. Garantie.........................................................................................................134

16. Appendice....................................................................................................134

NUENDO DD 8

1. Introduction

With the Nuendo DD 8 you have an incredibly versatile digital interface to your supply. What at first looks like a simple AES/TDIF/ADAT format converter turns out to be From small project studios to broadcast and television, the

Format Converter

today. The Nuendo DD 8 contains elaborate technology and the latest inte-

grated circuits, delivering 8 full channels in 24 bit and 96 kHz. The Nuendo DD 8 is a uniquely powerful and high-quality device, which will excite you even after many years of operation.

is the perfect link between the formats mostly used

the

universal problem solver at a closer look.

2. Package Contents

Please check that your Nuendo DD 8 package contains each of the following:

• Nuendo DD 8

• Manual

• Power chord

• Optical cable 2 x 2 m (TOSLINK)

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Universal

3. Brief Description and Characteristics

The Nuendo DD 8 consists of two up to 16-channel digital format converters in reference quality, in a standard 19" box with 1HU height. The compact device has numerous extraordinary features like Intelligent Clock Control (ICC), SyncCheck®, SyncAlign®, Bitclock PLL, patchbay functionality and active jitter suppression per SD-PLL. Switchable highend sample rate converters (SRC) allow for both sample rate conversion in best possible quality as well as clock-decoupling of all AES/EBU inputs.

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All of the Nuendo DD 8's I/Os support 96 kHz/24 bit. As ADAT optical and TDIF are restricted to 48kHz, in DS mode (Double Speed) two channels are being used for the transmission of one channel's data. The

Sample Split

algorithm used is also implemented in Steinberg’s Nuendo 96/52. Thus the Nuendo DD 8 also serves as an ideal AES/EBU frontend for these interface cards, on both Mac and PC.

The format conversion between AES/EBU and ADAT/TDIF operates in both directions at the same time, both completely independent or intelligently coupled. LEDs of different colours show the present state of incoming and outgoing signals and of the internal processing in a clear way.

The unique Intelligent Clock Control (ICC) allows for a flexible use with internal clock (44.1, 48, 88.2 and 96 kHz), external word clock or the digital input signals. These options being available for both directions are intelligently coupled in a way typical for Steinberg and easy to apply thanks to a clear and easily understandable display of the Lock and Sync states. Besides, the unique

Copy Mode

allows for operation as digital patchbay and signal distributor. Up to 16 channels can be distributed and converted at the same time. In few words: The Nuendo DD 8 is a true

Intelligent Audio Solution

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4. Technical Specifications

• Power supply: Internal, 100-240 V AC, 15 Watts

• Dimensions: 483 x 44 x 205 mm

• Weight: 2 kg

4.1 Inputs

AES/EBU

• 4 x XLR, transformer balanced, ground-free, according to AES3-1992

• High-sensitivity input stage (< 0.3 Vss)

• SPDIF compatible (IEC 60958)

• Accepts Consumer and Professional format, copy protection will be ignored

• Single Wire: 4 x 2 channels 24 bit, up to 96 kHz

• Double Wire: 4 x 2 channels 24 bit 48 kHz, equalling 4 channels 96 kHz

• Lock range: 27 kHz – 103 kHz

• Jitter when synced to input signal: < 3 ns

ADAT Optical

• 2 x TOSLINK, according to Alesis specification

• Standard: 8 channels 24 bit, up to 48 kHz

• Copy Mode: up to 2 x 8 channels 24 bit / 48 kHz

• Sample Split (S/MUX): 2 x 8 channels 24 bit / 48 kHz, equalling 8 channels 24 bit

96 kHz

• Bitclock PLL ensures perfect synchronisation even in varispeed operation

• Lock range: 33 kHz – 56 kHz

• Jitter when synced to input signal: < 2 ns

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TDIF

• 2 x D-sub 25 pol., according to TDIF-1

• Standard: 8 channels 24 bit, up to 48 kHz

• Copy Mode: up to 2 x 8 channels 24 bit / 48 kHz

• Sample Split (Dual Line): 2 x 8 channels 24 bit / 48 kHz, equalling 8 channels 24

bit 96 kHz

• SD-PLL for low jitter synchronisation even in varispeed operation

• Lock range: 27 kHz – 56 kHz

• Jitter when synced to input signal: < 3 ns

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Word Clock

• BNC, not terminated (10 kOhm)

• Automatic Double Speed detection and internal conversion to Single Speed

• SD-PLL for low jitter synchronisation even in varispeed operation

• AC-coupling, not effected by DC-offsets within the network

• Signal Adaptation Circuit: signal refresh through auto-center and hysteresis

• Overvoltage protection

• Level range: 1.2 Vss – 5.6 Vss

• Lock range: 27 kHz – 112 kHz

• Jitter when synced to input signal: < 3 ns

4.2 Outputs

AES/EBU

• 4 x XLR, transformer balanced, ground-free, according to AES3-1992

• Output voltage Professional 4.5 Vss, Consumer 2.1 Vss

• Format Professional according to AES3-1992 Amendment 4

• Format Consumer (SPDIF) according to IEC 60958

• Single Wire: 4 x 2 channels 24 bit, up to 96 kHz

• Double Wire: 4 x 2 channels 24 bit 48 kHz, equalling 4 channels 96 kHz

ADAT Optical

• 2 x TOSLINK

• Standard: 8 channels 24 bit, up to 48 kHz

• Copy Mode: up to 2 x 8 channels 24 bit / 48 kHz

• Sample Split (S/MUX): 2 x 8 channels 24 bit / 48 kHz, equalling 8 channels 24 bit

96 kHz

TDIF

• 2 x D-sub 25 pol., according to TDIF-1

• Standard: 8 channels 24 bit, up to 48 kHz

• Copy Mode: up to 2 x 8 channels 24 bit / 48 kHz

• Sample Split (Dual Line): 2 x 8 channels 24 bit / 48 kHz, equalling 8 channels 24

bit 96 kHz

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Word Clock

• BNC

• Max. output voltage: 5 Vss

• Output voltage @ 75 Ohm: 4.0 Vss

• Impedance: 10 Ohm

• Frequency range: 27 kHz – 56 kHz

4.3 Digital

• Low Jitter Design: < 1 ns internal

• Internal sample rates: 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz

• Internal resolution: 24 bit

4.4 Sample Rate Converter

• Self adjusting, high order aliasing filter (-110 dB)

• Resolution: 24 bit

• Dynamic range: 128 dBA

• Distortion (THD+N): -117 dB (0.00014%)

• Input / Output sample rate range: 27 kHz - 103 kHz

• Supports varispeed operation through fast tracking

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5. First Usage – Quick Start

The user interface of the Nuendo DD 8 is characterized by a clearly structured architecture and an unambiguous labelling of the front and rear sides. The device can thus be used without a manual without problems, because numerous LEDs show the state of the device and all incoming and outgoing signals in a strictly logical way.

However, we have to question this statement a little, because we couldn't stop ourselves and integrated everything in the Nuendo DD 8 that we could think of and that was in any way possible. As a consequence, you will find some application examples in chapter 10 that break up the logical structure of the front board. Those are however very special applications for professionals, where we anticipate both the understanding of those modes and the ability to read a manual.

When being switched on for the first time, the Nuendo DD 8 comes up in a default mode, which should be appropriate for most applications. Both converters are set to their typical format conversion modes, and synchronize to the input signals.

AES to ADAT/TDIF:

• SOURCE: AES

• SRC not active

• Slave mode (CLOCK AES / INPUT)

ADAT/TDIF to AES:

• SOURCE: ADAT

• Slave mode (CLOCK ADAT / INPUT)

• AES STATE PRO

If the device is being used with TDIF, only source TDIF instead of ADAT has to be selected in the right part.

The Nuendo DD 8 remembers all settings before switching off and sets them automatically when switching on the next time.

A quick guide for operation and functions of the Nuendo DD 8 can be found on the next pages (Tour de Nuendo DD 8).

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For transmission of the digital signals into a computer with PCI-bus, we recommend Steinberg's digital cards of the ST 24/96 and Nuendo 96/ 52 series. These high-quality digital interface cards are available with drivers for all common operating systems and have the highest reputation world-wide.

5.1 Tour de Nuendo DD 8

Join us for a small 'tour de Nuendo DD 8', starting on the left side at the AES to ADAT/TDIF converter. Configuration starts with choosing the input signal (AES, ADAT or TDIF). The state of the digital input signal at the 4 XLR sockets is displayed by 16 LEDs. Shown are lock (pro XLR socket, including SyncCheck), Emphasis and the level of the audio signal.

SRC activates a Hi-End 8-channel Sample Rate Converter. It is especially useful when sources cannot be synced or the output signal shall have another sampling frequency.

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Steinberg's intelligent clock control (ICC) offers extensive and professional means that are not easily met. To start with, the clock source can be set to Internal (crystal), External (BNC word clock) and Input, while Input lets you select between AES, ADAT or TDIF. The INT(ernal) clock rates are 44.1 and 48kHz, and 88.2 and 96kHz after activating the DS mode. After activating SRC, any AES signal from 32 to 96kHz can be converted to 44.1, 48, 88.2 or 96kHz. Lock state and clock synchronicity are being displayed by the state of each LED (flashing or constantly lit).

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The ADAT/TDIF to AES section is layed out in a similar way. After choosing the input signal (AES, ADAT or TDIF), the clock source and the sampling rate, there is a field with 16 LEDs for displaying the output state. An Emphasis bit at the TDIF input will be automatically set and indicated for the AES out. The lock state of the input signals is being displayed at the Input selector by flashing LEDs. The sync LEDs show the synchronicity between both ADAT or TDIF inputs, as in double speed mode (DS) 2 I/Os are active (4 channels each). The AES output signal can also be set to Consumer subcode. The first output (channel 1/2) can optionally be output optically (via TOSLINK) using the ADAT AUX port.

The unit always sends its output signal to ADAT and TDIF simultaneously. Additionally when operating at no higher than 48 kHz both ADAT outputs and TDIF interfaces get the same signal. Thus the distribution capability is doubled to 2 x ADAT and 2 x TDIF. Thanks to the possibility to freely select between inputs, all attached devices can send signals to each other without the need to rearrange the cabling between them.

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6. The AES to ADAT/TDIF Converter

6.1 General

The Nuendo DD 8'S functional unit, which will be called 'left part' further on, is an 8-channel format converter from AES/EBU to ADAT/TDIF, with the output signal being transmitted both at the ADAT and TDIF ports in parallel. As long as the device is not working in DS mode (Double Speed), the output signal is even present at both ADAT and TDIF ports (MAIN/AUX). Therefore the Nuendo DD 8 can pass on a 4 x 2 channel AES/EBU input signal to up to two ADAT and TDIF devices at the same time (splitter 1 to 4). If AES is chosen as source in the right part, there are the four AES/EBU outputs as well.

The four AES/EBU inputs process Double Speed (up to 96 kHz) and Double Wire (up to 48 kHz) automatically. Excessive status displays (Lock, SyncCheck, Emphasis, Level) help to avoid wrong configuration and wrong clock setup.

A switchable high-end 8-channel sample rate converter can both convert the sample rate and decouple the AES/EBU inputs.

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6.2 Inputs

At the rear side of the Nuendo DD 8 there are four XLR sockets for the AES/EBU inputs. Every input is transformerbalanced and ground-

free. Channel status and copy protection are being ignored. Thanks to a highly sensitive input stage, also SPDIF signals can be processed using a simple cable adapter (Phono/XLR).

To achieve this, pins 2 and 3 of an XLR plug are being connected to the two contacts of a Phono plug. The ground shield of the cable is only connected to pin 1 of the XLR plug.

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The inputs can be used in any combination, e. g. it is sufficient to connect an input signal only to input 3. In slave mode, this input is automatically being used as clock source. If more than one signal is present, the one furthest left is being used as clock source, i. e. the active input with the lowest number.

The inputs are being copied to the 8 channel ADAT/TDIF formats in logical order:

AES/EBU Input 1 2 3 4 ADAT/TDIF MAIN+AUX 1/2 3/4 5/6 7/8

If an input sample rate higher than 56 kHz is detected at the AES/EBU input, the DS LED lights up and the left part automatically switches to DS mode, using the following channel distribution:

AES/EBU 1L 1R 2L 2R 3L 3R 4L 4R ADAT/

TDIF

1/2

MAIN

3/4

MAIN

5/6

MAIN

7/8

MAIN

1/2

AUX

3/4

AUX

5/6

AUX

7/8

AUX

If a signal in Double Wire format is present at the input, technically no special processing is activated. There is no need for processing, because the output signals will be in Sample Split format (S/MUX, Double Line) right away.

6.3 Input State Display

The input state is displayed with 16 LEDs. Every input has its own LOCK LED. However a missing or invalid input signal is indicated by slow flashing of the SOURCE LED. As soon as a valid input signal is present the four LOCK LEDs will react per input. If ADAT or TDIF are chosen as input source (Copy Mode), all four LOCK and Emphasis LEDs show the same information. In DS mode, both two and two LEDs show the state of the MAIN (1/2) and the AUX (3/4) inputs.

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If a valid input signal is applied, SyncCheck is automatically active. When more than one input signal is present, the input with the lowest number serves as reference. If the AES input is not chosen as clock source, SyncCheck takes the chosen clock as reference and compares it with the input clocks. Inputs which are not synchronous are shown by quick flashing of the corresponding LOCK LED.

AES/EBU, S/PDIF and TDIF can contain an Emphasis information. Audio signals with Emphasis have a strong high-frequency boost and thus require a high-frequency attenuation on playback. If one of the inputs detects Emphasis, this information is being set at the TDIF output (and being transmitted correctly to a DTRS machine). The alerting red colour of the Emphasis LEDs has another reason:

❐

Emphasis is not available within the ADAT standard! This information is thus neither passed on to the ADAT output, nor taken into account later on for acoustic transmission!

Each channel's audio level is shown by a level LED. The green LED becomes active from -90 dBFS and above, a higher level yields brighter light. Thus only one LED is necessary to see if there is an audio signal or digital zero, only noise floor or a useful signal.

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6.4 Sample Rate Conversion

Each AES/EBU input has its own sample rate converter (SRC). An SRC allows for a conversion of the sampling rate in real-time. The 24 bit SRCs used in the Nuendo DD 8 work virtually without loss, i. e. there are no audible artefacts or noise signals. The SRC works so well that we could recommend to leave it switched on all the time, and thus eliminate any clock problem in the first place.

The Nuendo DD 8's SRC yields a maximum conversion ratio of 3:1 or 1:3. 96 kHz can be converted to any sample rate down to 32 kHz, 32 kHz to any rate up to 96 kHz.

If the internal clock is being used, the SRC works as a perfect jitter killer. But the Nuendo DD 8 allows for any source as clock reference. With other settings than INT, the device is slave as usual and the jitter of the output signal thus depending on the jitter of the clock source.

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An SRC is not only being used for conversion of sample rates and jitter suppression, it is especially useful for the so-called clock decoupling. By means of an SRC, any device which can't be synchronized (CD-Player, consumer DAT etc.) can be used within the system as if it was synchronizable. The SRC decouples any input clocks and sets the output clock to the common reference (no matter which one), and thus allows for bringing together various clock sources without any clicks or drop-outs.

Further information on sample rate conversion can be found in chapter 11, Technical Background.

6.5 Outputs ADAT Optical/TDIF

The Nuendo DD 8 provides two digital outputs, both in ADAT optical and TDIF-1 format. In normal operation only the MAIN outputs are used. When using more than the first 4 channels at activated DS (Double Speed), the AUX outputs also have to be used.

TDIF and ADAT optical outputs always operate simultaneously and carry the same audio data. As long as DS isn't activated MAIN and AUX also operate simultaneously and carry the same audio data. With this it is possible to distribute the output signal to two devices of the same format. When using all connectors the Nuendo DD 8 can feed up to 4 devices (2 x ADAT, 2 x TDIF).

The ADAT optical outputs of the Nuendo DD 8 are fully compatible to all ADAT optical inputs. A usual TOSLINK cable is sufficient for connection.

ADAT Main

Interface for the first or only device receiving an ADAT signal from the Nuendo DD 8. Carries the channels 1 to 8. When sending a Double Speed signal, this port carries the channels 1 to 4.

ADAT AUX

Copy of the data at the MAIN output. When sending a Double Speed signal, this port carries the channels 5 to 8. When AES STATE OPT is selected, ADAT AUX is used from the right part of the Nuendo DD 8 to send channels 1/2 in SPDIF format

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The TDIF-1 connectors of the Nuendo DD 8 are fully compatible to all devices with such an interface, for example DA-38 and DA-88. The connection is done through a special TDIF cable, available at your local dealer (Tascam part number PW-88D).

TDIF Main

Interface for the first or only device with a TDIF-1 interface. Carries the channels 1 to 8. When transmitting a Double Speed signal, this port carries the channels 1 to 4.

TDIF AUX

Copy of the data at the MAIN interface. Carries the channels 5 to 8 in Bit Split or Double Speed mode.

General tips for TDIF operation

TDIF and word clock

When the Nuendo DD 8 is slave, no additional word clock connection is necessary. In case DA88 and/or DA38 are slave, the word clock output of the Nuendo DD 8 has to be connected to the word clock input of the first (master) recorder. When using more than one recorder, a special sync cable (Tascam part number PW-88S) is needed.

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Emphasis

The AES/EBU and TDIF interface of the Nuendo DD 8 support Emphasis. Please note that an Emphasis indication will not be stored or processed on the sound when doing digital transfers between AES/EBU or TDIF and ADAT, because the ADAT standard does not include Emphasis.

6.6 Input ADAT/TDIF (Copy Mode)

By means of the SOURCE button, ADAT and TDIF are available as signal sources in the left part as well. Thus the Nuendo DD 8 turns into a unique ADAT to TDIF and TDIF to ADAT converter, a digital patch bay and signal distributor. These two source formats are notified with a yellow LED, after all they are the main inputs for the right part, i. e. the ADAT/TDIF to AES/EBU converter, for which they are still available as inputs. Please refer to the block diagram on page 29.

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In this operating mode, which is called

Copy Mode

due to its identical source and destination format, the input signal can be forwarded to a same format without having to change cables externally. The mathematical equation is

• (2 x ADAT In or 2 x TDIF In) to (2 x ADAT Out plus 2 x TDIF Out)

In other terms: The ADAT or TDIF input signal appears in parallel at the ADAT and TDIF outputs. And the MAIN and AUX ports can be used to pass through / distribute up to 16 channels at the same time.

In addition to the already described feature of signal distribution, the Nuendo DD 8 thus also works as a patch bay, because the ADAT and TDIF devices connected to the Nuendo DD 8 can exchange data directly among each other without re-connecting of cables. An ADAT optical or TDIF input signal is being output at two ADAT optical and two TDIF ports at the same time.

Please take a look at the block diagram on page 29. It shows the whole signal routing inside the Nuendo DD 8 in a clear way, also for this

Mode

❐

The sample rate converter is a part of the AES/EBU inputs, so when select-

Copy

ing ADAT/TDIF it is still only available to the AES inputs. The AES inputs (including the SRC) can also be used by the right part of the Nuendo DD 8 if necessary.

If the Copy Mode is active, the DS mode can be activated manually with the button for the sampling frequency. There is a reason for this: normally, the 8 channel input signal of the ADAT or TDIF MAIN input is copied to both outputs MAIN/AUX (splitter). But if a Sample Split, S/MUX or Double Wire signal is present at the ADAT or TDIF input, also the data of the AUX input has to be passed on to the AUX output for full transmission of 8 channels. In other terms: 16 channels are being forwarded 1:1.

❐

In order to make use of all 16 TDIF and ADAT channels in Copy Mode, DS has to be activated, even if it is only Single Speed signals.

The level display then works like in Sample Split operation. Two channels are being displayed on one LED (1+2, 3+4 etc.).

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Emphasis

7. The ADAT/TDIF to AES/EBU Converter

7.1 General

The Nuendo DD 8's functional unit called 'right part' further on, is an 8channel format converter from ADAT/TDIF to AES/EBU.

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Because the tain a coding, the Nuendo DD 8 cannot distinguish them from normal (44.1/48 kHz) material. Whether the AES/EBU outputs are supposed to work in Single (44.1/48 kHz) or Double Speed (88.2/96 kHz) has to be set explicitly by the user. This happens in the clock section with the sample frequency button, activating DS.

Complete status displays (Lock, SyncCheck, Emphasis, Level) help to avoid wrong configuration and wrong clock setup.

Double Wire

and

Sample Split

(S/MUX) formats don't con-

7.2 Inputs

The Nuendo DD 8 provides two digital inputs, both in ADAT optical and TDIF-1 format. The key SOURCE sets the desired input active.

In normal operation only the MAIN inputs are used. When using more than the first 4 channels at activated DS (Double Speed), the AUX inputs also have to be used.

The input data is passed on to the four AES/EBU outputs in logical order:

ADAT/TDIF 1 2 3 4 5 6 7 8 AES/EBU 1L 1R 2L 2R 3L 3R 4L 4R

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If the input data is encoded with Sample Split, S/MUX or Double Line, the AES output has to be set to DS mode manually. Every input contains the information of only 4 channels, for full 8 channels MAIN

and

AUX have to be used. 16 input channels 44.1/48 kHz are being converted to 8 output channels 88.2/96 kHz. The channels are being distributed in the following manner:

ADAT/TDIF MAIN+AUX

AES/EBU 1L 1R 2L 2R 3L 3R 4L 4R

1/2

MAIN

3/4

MAIN

5/6

MAIN

7/8

MAIN

1/2

AUX

3/4

AUX

5/6

AUX

7/8

AUX

The ADAT optical inputs of the Nuendo DD 8 are fully compatible with all ADAT optical outputs. Steinberg's unsurpassed Bitclock PLL prevents clicks and drop outs even in extreme varipitch operation, and guarantees a fast and low jitter lock to the digital input signal. A usual TOSLINK cable is sufficient for connection.

ADAT Main

Interface for the first or only device sending an ADAT signal to the Nuendo DD 8. Carries the channels 1 to 8. When receiving a Double Speed signal, this input carries the channels 1 to 4.

ADAT AUX

Interface for the second device sending a Double Speed signal to the Nuendo DD 8. Carries the channels 5 to 8. Receives channels 9-16 in Copy Mode.

The TDIF-1 connectors of the Nuendo DD 8 are fully compatible with all devices offering such an interface, for example DA-38 and DA-88. A SDPLL ensures best playback sound quality and reliable operation. SyncCheck verifies synchronous operation when using both TDIF ports. The connection is done through a special TDIF cable, available at your local dealer (Tascam part number PW-88D).

TDIF Main

Interface for the first or only device with a TDIF-1 interface. Carries the channels 1 to 8. When transmitting a Double Speed signal, this port carries the channels 1 to 4.

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TDIF AUX

Carries the channels 5 to 8 in Double Speed mode. Transmission of channels 9-16 in Copy Mode.

General tips for TDIF operation

TDIF and word clock

7.3 Input State Display

The input state is being displayed by means of 16 LEDs. A missing or invalid input signal is indicated by slow flashing of the SOURCE LED. In case ADAT or TDIF are selected all four SYNC and Emphasis LEDs are showing the same information. In DS mode both two and two LEDs show the state of the MAIN (1/2) and the AUX (3/4) inputs.

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If MAIN and AUX are not synchronous to each other, the corresponding input's SYNC LEDs will be quickly flashing. If the input is not chosen as clock reference, SyncCheck takes the chosen clock (internal, external etc.) as reference and compares it to the clocks of the inputs. Non synchronous inputs will be indicated by quick flashing of the corresponding SYNC LEDs.

If the TDIF input signal contains emphasis information, all four EMPHASIS LEDs in the output state area will light up. The AES/EBU output channel status will then be changed from 'no emphasis' to '50/15 µs' (emphasis). Because this coding cannot be changed manually, and unfortunately does not necessarily have to be correct in the source, we chose red LEDs to give both a note and warning.

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7.4 Outputs AES/EBU

At the rear side of the Nuendo DD 8 there are four XLR sockets for the AES/EBU outputs. Every output is transformer-balanced, ground-free and compatible to all devices with AES/EBU port. Connection is accomplished using balanced cables with XLR plugs.

If AES STATE PRO (Professional) is chosen, the output level is almost 5V. If CON (Consumer) is chosen, the output signal will have a channel status compatible to SPDIF. As far as we know, every SPDIF device should be capable of handling an input signal of up to 5V instead of the usual

0.5V. Nevertheless the output level will be reduced to 2V when CON is selected.

Connecting devices with coaxial SPDIF ports to the Nuendo DD 8 is accomplished with simple cable adapters (XLR/Phono).

To achieve this, pins 2 and 3 of an XLR plug are being connected to the two contacts of a Phono plug. The ground shield of the cable is only connected to pin 1 of the XLR plug.

Additionally, there is the possibility of using the second ADAT output as optical SPDIF output. If AES STATE OPT is chosen, the channels 1/2 will also be transmitted via ADAT AUX.

Digital signals in SPDIF or AES/EBU format contain a channel status coding besides the audio data, which is being used for transmitting further information. The output signal coding of the Nuendo DD 8 has been implemented according to AES3-1992 Amendment 4.

• 32 kHz, 44.1 kHz, 48 kHz, 64, kHz, 88.2 kHz, 96 kHz according to sample rate

• Audio use

• No Copyright, Copy permitted

• Format Consumer oder Professional

• Category General, Generation not indicated

• 2-Channel, No Emphasis oder 50/15 µs

• Aux Bits Audio use, 24 Bit

• Origin: Nuendo DD 8

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❐

Note that most consumer-orientated equipment (with optical or phono SPDIF inputs) will only accept signals in ‘Consumer’ format!

The status 'Professional' should always be active when sending data to a device with AES/EBU input (when the XLR connectors are used).

7.5 Input AES/EBU (Copy Mode)

With the SOURCE button, AES/EBU can be chosen as the source for the right part, in addition to ADAT or TDIF. The Nuendo DD 8 then turns into a unique 8 channel AES/EBU to AES/EBU sample rate converter, line buffer, signal refresher and signal distributor. This input format is indicated by a yellow LED, after all it is the main input for the left part (the AES/EBU to ADAT/TDIF converter), for which it is still available as input. Please refer to the block diagram on page 29.

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In this operating mode, which is called source and destination formats, the input signal can be forwarded to a same format without having to change cables externally.

In addition to the already described feature of signal distribution, the Nuendo DD 8 thus works as a patch bay, because the AES/EBU devices connected to the Nuendo DD 8 can exchange data directly among each other without re-connecting of cables.

Please take a look at the block diagram on page 29. It shows the whole signal routing inside the Nuendo DD 8 in a clear way, also for this

Mode

Copy Mode

due to its identical

Notes on special functions

In the operating mode AES to AES, which is only available in the right part, the Nuendo DD 8 has several special features. The right INPUT STATE Display does then work exactly like the left one and does therefore display LOCK/SYNC and EMPHASIS for each AES input.

❐

If AES is chosen as source and only one AES input is supplied with a valid signal, the Nuendo DD 8 switches to a distribution mode. The input signal will then be copied to all outputs (splitter 1 to 4). Therefore all level LEDs (instead of only two) will light up.

Copy

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While in the left part an AES Double Speed signal (sample rate > 56 kHz) is being indicated automatically by the DS LED, this is not the case in the right part. If you are not sure about the input sampling frequency, you can still check it in the left part (by switching to AES source for a moment).

❐

The reason for the missing automatism is the ability to convert Double Wire to Single Wire and Single Wire to Double Wire. This is controlled by manual activation of the DS function.

• If an AES signal in Double Wire format is present (carrier 32 to 48 kHz) and DS is activated, the data split into up to 8 channels is being converted into the original up to 4 channels Single Wire (64 to 96 kHz, output in Double Speed).

• This is also true for ADAT (S/MUX) and TDIF (Double Line). These signals can also be converted to single wire double speed AES/EBU in the right part.

• If a single wire Double Speed AES signal (64 to 96 kHz) is present, the first 4 channels will be converted to 8 channels Double Wire (32 to 48 kHz) with DS deactivated.

All those conversions are loss-less, the available samples will only be put together or distributed between the channels.

In AES to AES mode the SRC is also available. Also placed on the left side of the front panel, it then works for the right part of the device. This is indicated by a quick alternating flashing of the SRC and the right AES SOURCE LED. If the SRC is active, the conversion between Single Wire and Double Wire as described above are not available. The DS function only sets the output sample rate.

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8. Clock Section

8.1 Clock Configuration

The Nuendo DD 8 has an almost identical clock section in the left and right part, with professional capabilities that are hard to meet. The unique ICC technology (Intelligent Clock Control) allows for a flexible use of both functional units with internal clock (44.1 and 48 kHz, 88.2 and 96 kHz in DS mode), external word clock or the digital input signals. All options are intelligently coupled and easily applicable and understandable, thanks to a clear display of the corresponding lock state.

As clock source, INTERNAL (crystal), EXTERNAL (BNC word clock) and INPUT (the digital input signal AES/TDIF/ADAT) can be chosen. If the clock signal is present, the corresponding LED will light constantly, if it is not present, the LED will flash.

❐

If the SRC is active and AES is chosen as signal source in both parts, the right part's clock LEDs will be inactive, because two different clock settings for one signal is not possible.

If AES is chosen as signal source in both parts, and the SRC is not active, both clock sections remain active. By this it is avoided that the present clock setting is lost for a short moment when stepping through the inputs on one side. Please note that in this case an identical left and right clock setting should be selected. Nuendo DD 8 will help you detect wrong settings as SyncCheck reliably indicates wrong or unequal settings.

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INPUT

As displayed on the front panel, the CLOCK SOURCE for the INPUT setting can be the AES, TDIF or ADAT input. This selection is independant from the signal source. If the signal source is set to AES, the clock source can still be ADAT, given that a valid ADAT signal is available. A missing or invalid clock source signal is indicated by slow flashing of the corresponding LED.

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EXT.

With EXTERNAL, the Nuendo DD 8's word clock input is used as clock reference. The LED will flash slowly, if the word clock is missing or unusable.

INT

For INTERNAL, 44.1 kHz or 48 kHz sampling rate is available. If DS is active in the left part, the data will be transmitted in Sample Split format (S/MUX, Double Line). If DS is active in the right part, the output sample rate doubles to 88.2 kHz or 96 kHz.

❐

For the INTERNAL clock setting it is mandatory that the clock rate of the sources is synchronous to the Nuendo DD 8. Therefore the external device has to be synchronized to the Nuendo DD 8's word clock out or AES/TDIF/ ADAT out.

The Nuendo DD 8 thus has to be master, all devices connected to it slave (exception: SRC mode). In order to avoid clicks and drop outs in this operating mode due to faulty or missing synchronicity, a special process called SyncCheck compares the incoming data and the Nuendo DD 8's internal clock. Like LOCK, SYNC is indicated by flashing (error) or constantly lit (OK) LED. While LOCK is also indicated with the source LEDs, SyncCheck steers the four SYNC LEDs. Besides, the flashing frequency is twice as high.

8.2 Lock, SyncCheck and SyncAlign

Digital signals consist of a carrier and the data. If a digital signal is applied to an input, the receiver has to synchronize to the carrier clock in order to read the data correctly. To achieve this, the receiver has a PLL (Phase Locked Loop). As soon as the receiver has locked to the exact frequency of the incoming signal, it is locked. This even with small changes of the frequency, because the PLL tracks the receiver's frequency.

If an AES, TDIF or ADAT signal is applied to the Nuendo DD 8, the corresponding input LED stops flashing. The device indicates LOCK, i. e. a valid input signal.

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Lock

state remains

Unfortunately, LOCK does not necessarily mean that the received signal is correct with respect to the clock processing the read out of the embedded data. Example [1]: The Nuendo DD 8 is set to 44.1 kHz internal and a CD-Player is connected to input AES1. The INPUT LED will show LOCK immediately, but the CD-Player's sample rate is generated internally, and thus slightly higher or lower than the Nuendo DD 8's internal sample rate. Result: When reading out the data, there will frequently be read errors that cause clicks and drop outs.

Also when using multiple inputs, a simple LOCK is not sufficient. The above described problem can be solved elegantly by setting the Nuendo DD 8 from INT to INPUT (its internal clock will then be the clock delivered by the CD-Player). But if you now connect a DAT recorder as a second source, there will again be a slight difference in the sample rate, and therefore clicks and drop outs [2]. Another example could be connecting to ADAT machines which are not synchronous to each other due to wrong clock setup [3].

In order to display those problems optically at the device, the Nuendo DD 8 contains SyncCheck®. It checks all clocks used for synchronicity. If

they are not synchronous to each other (i. e. absolutely identical), the SYNC LED of the asynchronous input flashes. In example 1 it would have been obvious at once that the SOURCE AES LED was constantly lit when connecting the CD-Player, but that the SYNC LED was flashing. In example 2, all LEDs would be constantly lit except the SYNC LED of the input used by the DAT. In example 3, two LEDs are constantly lit, while two others are flashing.

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In practice, SyncCheck allows for a quick overview of the correct configuration of all digital devices. So one of the most difficult and errorprone topics of the digital studio world finally becomes easy to handle.

A special problem occurs with devices offering several AES or SPDIF inputs. While with ADAT and TDIF all 8 channels share the same clock base, with AES there are several completely independant receivers with own PLLs and data buffers. Therefore there can be a random error of ± 1 sample difference between the stereo pairs. The Nuendo DD 8's exclusive SyncAlign® technology avoids this effect and guarantees sample synchronicity among all 4 stereo channels.

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Unfortunately, this method does not work automatically when the SRC is active. For this reason, the SRC must be switched on and off once when all AES sources have been connected and stable SYNC is displayed. All four SRCs do now operate in sync with sample accuracy. (This is only relevant, if you wish to convert a multi channel signal from one source only – e.g. from a mixer or a tape recorder – using SRC.

8.3 Word Clock Input and Output

Input

The Nuendo DD 8's word clock input is available to both the left and the right part. It is active, when EXT is chosen in the clock section. The signal at the BNC input can be single or double speed, the Nuendo DD 8 automatically adapts to it. As soon as a valid signal is detected, the EXT LED is constantly lit, otherwise it is flashing.

Thanks to the

Signal adaptation Circuit

, the word clock input still works correctly even with heavily mis-shaped, dc-prone, too small or overshoot-prone signals. Thanks to automatic signal centering, 300 mV (0.3V) input level are sufficient in principle. An additional hysteresis reduces sensitivity to 1.2 V, so that over- and undershoots and high-frequency disturbances don't cause a wrong trigger.

The Nuendo DD 8's input is designed with high resistance in order to yield maximum flexibility for the user. If correct termination is required, a 75 Ohm termination resistor is necessary (see

nation

11.2 Cabling and Termi-

Output

The word clock output is constantly active and basically delivers the sample rate of the left part as word clock signal. As long as it is working with internal clock, the output word clock is especially jitter-free (< 1 ns). The device can even be used as a central word clock generator (except the limitation of only one output). In slave mode (EXT/INPUT), the amount of jitter is depending on the input signal.

A word clock signal fed to the Nuendo DD 8 can even be passed through via the word clock output, because the output signal is phase locked to the input signal (0˚). Thus the usual T-adaptor at the input is not needed and the Nuendo DD 8 works as a signal refresher. This ap-

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plication is even more interesting, because the exceptional input of the Nuendo DD 8 (1 Vss sensitivity instead of the usual 2.5 Vss, dc cut, Signal Adaptation Circuit) guarantees a secure function also with critical word clock signals.

❐

The Nuendo DD 8's word clock output is derived from the left part, because the TDIF ports need a fixed word clock reference.

For this reason, the word clock signal derived from AES, TDIF and ADAT has a phase shift of 90˚ at the output. This has no effect when being used with AES or ADAT, because these formats don't require a certain relation to the word clock signal.

❐

The wordclock output as well as all ADAT and TDIF ports always operates in Single Speed mode only. At 96 kHz, the word clock output will therefore be a 48 kHz signal.

Thanks to a low impedance, but short circuit proof output, the Nuendo DD 8 delivers 4 Vss to 75 Ohms. For wrong termination with 2 x 75 Ohms (37.5 Ohms), there are still 3.2 Vss at the output.

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9. Word Clock

9.1 Operation and Technical Background

In the analogue domain one can connect any device to another device, a synchronization is not necessary. Digital audio is different. Correct interpretation of digital audio data is dependent upon a definite sample frequency. Signals can only be correctly processed or transferred between devices if these all share the same clock, otherwise digital signals are misinterpreted, causing distortion, clicks/crackle and even dropouts.

AES/EBU, SPDIF and ADAT optical are self-clocking (seen from a nontechnical view TDIF also, as word clock is embedded into the TDIF cable), so an additional line for word clock could be considered redundant. In practice however, using several devices at the same time can cause problems. For example, if devices are connected in a loop without there being a defined ‘master’ device, self-clocking may break down. Besides, the clocks of all devices must be synchronized from a single source. Devices without S/PDIF inputs (typically playback devices such as CD players) cannot be synchronized via self-clocking. Finally there are 'problematic' devices, which are nearly un-usable without a word clock attached.

In digital studios, synchronization requirements can be met by connecting all devices to a central sync source. For instance, the master device could be a mixing desk, sending a reference signal - word clock - to all other devices. However, this will only work if all the other devices have word clock or sync inputs (e.g. some professional CD players), allowing them to run as slaves. This being the case, all devices will receive the same clock signal, so there is no fundamental reason for sync problems when they are connected together.

But word clock is not only the 'great problem solver', it also has some disadvantages. The word clock is based on a fraction of the really needed clock. For example SPDIF: 44.1 kHz word clock (a simple square wave signal) has to be multiplied by 128 or 256. This signal then replaces the one from the quartz crystal. Because of the high multiplication factor the reconstructed clock will have great deviations called jitter. The jitter caused by word clock is typically 15 times higher as when using a quartz based clock.

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