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Frequently Asked Questions

Power

Power:

Q: Can I run SDI

Q: Can I run SDI----MADI with just one PSU (AC inlet) cable?

MADI with just one PSU (AC inlet) cable?

A: Yes, although it is always recommended that two AC inlet cables
are connected in order to provide a level of redundancy. The two AC
inlet cables should be connected to mains circuits which are as
independent of each other as possible.

SDI

SDI:

Q: How do you select between SDI formats?

A: The XLogic SDI-MADI automatically determines what the incoming
SDI format is and configures itself accordingly. Status of each
individual SDI input (SD, HD or 3G) is indicated on the front panel.

Synchronisation:

Q: SDI

Q: SDI----MADI is not synchronising to wordclock.

MADI is not synchronising to wordclock.

A: Ensure that the incoming wordclock is derived from a 75 ohm
terminated source, as per the AES-11 standard.

Q: What is the most commonly recommended configuration for

Q: What is the most commonly recommended configuration for
synchronisation?

synchronisation?

A: The most commonly used and recommended synchronisation
method for SDI-MADI is slaving it to wordclock via the Ref In
connector. Ensure that wordclock sync has been selected using the
front

panel selection switch (WK LED should illuminate) and that all four
sample rate converter switches are set to ON.

Q: Can I daisy

Q: Can I daisy----chain other devices to SDI

chain other devices to SDI

chain other devices to SDI----MADI to when synchronising

MADI to when synchronising

to Wordclock?

A: This is possible by using the wordclock loop-through connector (WK
Out). WK Out is a buffered copy of the incoming wordclock.

Q: Can SDI

Q: Can SDI----MADI be used as a master sync generator?

MADI be used as a master sync generator?

A: In the majority of installations SDI-MADI should not be used as a
master sync generator. The only situation that would dictate use as a
master clock reference would be when SDI-MADI is synchronised to an
incoming SDI source that contains Dolby® bit streams. In this
situation the appropriate SDI’s Sample Rate Converter (SRC) switch
should be set to OFF and all other external audio equipment should
be synchronised to the SDI-MADI’s wordclock output (WK Out).

Q: Is the wordclock input terminated?

A: Yes, it is internally terminated at 75 ohms.

Sample Rate Converters:

Q: What are the Sample Rate Converters for?

A: In the traditional sense, Sample Rate Converters (SRC) do as they
say; convert an incoming or outgoing audio source from one sample
rate to another. In the case of SDI-MADI, the SRCs perform two
functions:

a) The sample rate converters compensate for any minor frequency

differences between the incoming SDI 48 kHz and the reference
48 kHz, thus locking the audio to the reference 48 kHz.

b) The sample rate converters are used to phase align the audio

content within the independent SDI sources prior to them being
combined and transmitted as a MADI stream. Unless
synchronising to an SDI source that incorporates Dolby ®
encoded material it is important to ensure that all four SRC
switches are set to ON. If set to OFF it could be possible for
audible clicks to be present on the MADI receiving device. Note:
If SDI-MADI detects that phase alignment between incoming SDI
streams is significantly out (and that all SCRs are set to OFF),
SDI-MADI will mute the MADI output.

Q: When should an SRC switch be set to OFF?

A: The only time an SRC switch should be set to OFF is when Dolby ®
content is embedded within the SDI stream. If this situation does
arise then SDI-MADI synchronisation must be set to reference that
specific SDI input. SDI-MADI will then become the sync master
reference source. Ensure that other equipment then synchronises to
the unit’s Wordclock output (WK Out).

Note: only one SRC should be set to OFF at any one time. The
possibility of sync issues could arise if the separate SDI sources are
not phase aligned.

Q: Can Sample Rate Conversion be applied to the AES outputs?

A: Yes, depending whether the SRCs are set to ON or not. If set to OFF,
synchronisation of each AES pair will be as per the specific input SDI
source.

Audio Outputs:

Q: Is there an easier way to access the AES outputs than wiring

Q: Is there an easier way to access the AES outputs than wiring
directly to the 37

directly to the 37

directly to the 37----way Dsub?

way Dsub?

A: Yes, SSL also manufacture a 1U AES3-id breakout unit (ASBO) that
connects directly to SDI-MADI and provides the 32 unbalanced AES
outputs on BNC connectors (75 ohm). Contact your SSL dealer for
further information.

Q: Are the audio outputs always available?

A: Yes, de-embedded audio is simultaneously available as 32 x AES3-
id, and optical & coaxial MADI.

Q: What fibre optic MADI cable should I use?

Recommended fibre types are 62.5/125

m or 50/125

m, multimode.

An ST type fibre optic connector is fitted to SDI-MADI.

Q: I have no MADI output?

A: Check that synchronisation is valid. MADI will not be transmitted if
synchronisation is invalid.