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User's Guide ADI-6432R BNC   © RME

 

 

15.2 Lock, SyncCheck and SyncAlign 
 

Digital signals consist of a carrier and the data. If a digital signal is applied to an input, the re-
ceiver has to synchronize to the carrier clock in order to read the data correctly. To achieve this, 
the receiver uses a PLL (Phase Locked Loop). As soon as the receiver meets the exact fre-
quency of the incoming signal, it is locked. This 

Lock

 state remains even with small changes of 

the frequency, because the PLL tracks the receiver's frequency. 
 
If an AES signal is applied to the ADI-6432, the corresponding SYNC LED starts flashing. The 
unit indicates LOCK, i. e. a valid input signal (in case the signal is also in sync, the LED is con-
stantly lit, see below). 
 
Unfortunately, LOCK does not necessarily mean that the received signal is correct with respect 
to the clock which processes the read out of the embedded data. Example [1]: The ADI-6432 is 
set to 44.1 kHz internal clock, and a CD-Player is connected to input AES1. The corresponding 
LED will start flashing immediately, but the CD-Player's sample rate is generated internally, and 
thus slightly higher or lower than the ADI-6432'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 ADI-6432 from internal clock to AES (its internal clock will 
then be the clock delivered by the CD-Player). But in case a DAT recorder is connected as a 
second source, there will again be a slight difference in the sample rate, and therefore clicks 
and drop outs [2]. 
 
In order to display those problems optically at the device, the ADI-6432 includes 

SyncCheck

. It 

checks all clocks used for 

synchronicity

. If they are not synchronous to each other (i. e. abso-

lutely identical), the SYNC LED of the asynchronous input flashes. In example 1 it would have 
been obvious that the SYNC AES1 LED kept on flashing after connecting the CD-Player. In 
example 2, SYNC AES1 would be constantly lit, but the SYNC LED of the input used by the 
DAT would be flashing. 
 
In practice, SyncCheck allows for a quick overview of the correct configuration of all digital de-
vices. This way one of the most difficult and error-prone 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 MADI 
all 64 channels share the same clock base, with AES there are several completely independent 
receivers with their own PLLs and data buffers. Therefore a random error of ± 1 sample differ-
ence between the stereo pairs can occur. The ADI-6432's exclusive 

SyncAlign

 technology 

avoids this effect and guarantees sample synchronicity among all four stereo channels.  

Summary of Contents for ADI-6432(r)

Page 1: ...Digital Interface SyncAlign TM SyncCheck TM Intelligent Clock Control TM SteadyClock TM Hi Precision 24 Bit 192 kHz 64 Channel Bidirectional Format Converter MADI AES 3id Interface MIDI embedded in MA...

Page 2: ...UT 14 8 3 AES 14 8 4 CLOCK 15 8 5 REMOTE 15 9 Inputs 9 1 MADI 16 9 2 AES 3id 16 10 Outputs 10 1 MADI 17 10 2 AES 3id 17 11 Word Clock 11 1 Word Clock Input and Output 18 11 2 Technical Description and...

Page 3: ...ral 31 14 6 Firmware 32 14 7 Connector Pinout RS232 32 14 8 MADI User Bit Chart 32 15 Technical Background 15 1 Terminology 33 15 2 Lock SyncCheck and SyncAlign 34 15 3 MADI Basics 35 15 4 SteadyClock...

Page 4: ...isture and water from entering the device Never leave a pot with liquid on top of the device Do not use this product near water i e swimming pool bathtub or wet basement Danger of condensation inside...

Page 5: ...User s Guide ADI 6432R BNC RME 5 User s Guide ADI 6432R BNC General...

Page 6: ...erates in both directions at the same time LEDs of different colours show the pre sent state of incoming and outgoing signals and of the internal processing in a clear way The unique Intelligent Clock...

Page 7: ...sive SyncCheck indicates via flashing LEDs if one of these inputs is locked but not synchronous to the chosen clock reference WORD INPUT displays the basic state of the word clock input signal ERROR D...

Page 8: ...s Used for transmission of MIDI data via MADI and for remote control of the ADI 6432 COM 9 pin D sub Serial interface for data transmission via MADI IEC receptacle for power connection The specially d...

Page 9: ...in the CLOCK SECTION The but tons CLOCK let you step through the options external clock AES MADI word and internal clock 44 1 or 48 kHz The button STATE sets the range for the internal but also the e...

Page 10: ...have regional specific warranty implications In any case warranty does not cover damage caused by improper installation or maltreatment replacement or repair in such cases can only be carried out at t...

Page 11: ...onable protec tion against harmful interference in a residential installation This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the...

Page 12: ...ct has to be recycled at the end of its lifetime In case a disposal of electronic waste is not possible the recycling can also be done by IMM Elektronik GmbH the manufacturer of the ADI 6432 For this...

Page 13: ...User s Guide ADI 6432R BNC RME 13 User s Guide ADI 6432R BNC Usage and Operation...

Page 14: ...48k frame format 8 2 MADI OUTPUT The buttons FRAME and FORMAT configure the MADI output signal as follows FRAME 48k or 96k frame 48k frame can be used with Single Double and Quad Speed 96k frame is li...

Page 15: ...hing error or constantly lit OK LED The button STATE is used to configure the ADI 6432 and with this all of its outputs to the fre quency ranges Single Speed Double Speed or Quad Speed No LED Single S...

Page 16: ...t not ground free The BNC sockets are con nected to the housing GND Channel status and copy protection are being ignored The inputs can be used in any combination e g it is sufficient to connect an in...

Page 17: ...nnec tors Every output is transformer coupled but not ground free The BNC sockets are connected to the housing GND The output s channel status coding has been implemented according to AES3 1992 Amendm...

Page 18: ...e back beside the BNC jacks Use a small pencil or similar and carefully push the blue switch so that it snaps into its lock position Another push will release it again and de activate the termination...

Page 19: ...lock 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 sig...

Page 20: ...he higher voltage word clock networks are in some cases more stable and reliable if cables are not terminated at all Ideally all outputs of word clock delivering devices are designed as low impedance...

Page 21: ...to MADI A MIDI cable con necting MIDI output and MIDI input of the ADI 6432 will realize a direct pass through of MIDI from MADI input to MADI output 12 2 Remote Controlling the ADI 6432 The ADI 6432...

Page 22: ...the MIDI Out of the ADI 6432 At the same time they reach the 6432 s CPU The MIDI sig nals of external devices travel via MIDI In and MADI Out back to the software together with the request responses o...

Page 23: ...via MADI the ADI 6432 also transmits serial data via user bits in this case on channels 1 to 9 Supported are the Baud rates 9600 19200 38400 and 115200 The configuration is done via MIDI either by se...

Page 24: ...box computer unveils a delay the so called offset between playback and recording If a signal is played back from the MADI PCI and recorded again via MADI by performing an AES loopback the record track...

Page 25: ...User s Guide ADI 6432R BNC RME 25...

Page 26: ...cts units In this applica tion the ADI 6432 serves to insert digital devices into the MADI data stream or as adder of ad ditional signals to the not fully utilized MADI data stream Example A mixing de...

Page 27: ...converter Its AES outputs are connected to the AES inputs of the second ADI 6432 The second ADI 6432 is used as de scribed in the above example sending the MADI input signal directly to the MADI outp...

Page 28: ...28 User s Guide ADI 6432R BNC RME...

Page 29: ...User s Guide ADI 6432R BNC RME 29 User s Guide ADI 6432R BNC Technical Reference...

Page 30: ...Hz Jitter when synced to input signal 1 ns Jitter suppression 30 dB 2 4 kHz Word Clock BNC not terminated 10 kOhm Switch for internal termination 75 Ohm Automatic Double Quad Speed detection and inter...

Page 31: ...k frame RS 232 9 pin D sub Invisible transmission via User bit of channels 1 to 9 14 4 Digital Clocks Internal AES In MADI In Word clock In Low Jitter Design 1 ns in PLL mode all inputs Internal clock...

Page 32: ...this manual the unit is shipped with firmware 1 5 The firmware version is displayed after power on for about one second by the SYNC and AUDIO LEDs of the AES INPUT STATE section 14 7 Connector Pinout...

Page 33: ...data rate and hence twice the sample rate A stereo signal subsequently requires two AES EBU ports The Double Wire method is an industry standard today however it has a number of different names like D...

Page 34: ...simple LOCK is not sufficient The above described problem can be solved elegantly by setting the ADI 6432 from internal clock to AES its internal clock will then be the clock delivered by the CD Playe...

Page 35: ...ced coaxial cables with 75 Ohms BNC plugs they are not expensive and easy to get The optical interface is much more interesting due to its complete galvanic separation but for many users it is a myste...

Page 36: ...kHz SteadyClock has originally been de veloped to gain a stable and clean clock from the heavily jittery MADI data signal The embedded MADI clock suffers from about 80 ns jitter caused by the time res...

Page 37: ...User s Guide ADI 6432R BNC RME 37 16 Block Diagram...

Page 38: ...of all value response data bytes Value Response After being triggered by receiving a request value command device sends a string of all value response data bytes Message type is set to 30h Set Value S...

Page 39: ...16 AES lock 13 16 x bit 0 3 lock 13 16 bit 4 7 0 11h 17 AES lock 17 20 x bit 0 3 lock 17 20 bit 4 7 0 12h 18 AES lock 21 24 x bit 0 3 lock 21 24 bit 4 7 0 13h 19 AES lock 25 28 x bit 0 3 lock 25 28 b...

Page 40: ...ES 5 1 clock select 3 MADI 4 WCK 4 LSB 0 clock select 3 0 2 0 1 MSB 1 clock state 0 single speed 1 ds 2 qs LSB 0 LSB 0 clock state 02h 2 info byte 1 MSB 7 0 6 MADI input override 5 MADI lock 4 MADI sy...

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