Z-Systems z-8.8a Lightpipe digital detangler - Manual (Page 5)

z-8.8a Digital Detangler instruction manual z-systems audio engineering, 2000
Lightpipe and ADAT are trademarks of Alesis Corporation
5
How to convert to and from S/PDIF
One of the z-8.8a's most powerful features is its built-in conversion between S/PDIF and ADAT
Optical formats. The z-8.8a allows you to do bidirectional transfers between S/PDIF and ADAT
Optical, even if the sources and destinations are asynchronous or at totally different sample rates
from one another and from the ADAT! This is because the z-8.8a has eight defeatable channels of
internal sample rate conversion.
When making digital transfers to an ADAT, the ADAT needs all eight of its digital input channels
to be at exactly the same sample rate, with the digital samples lined up to start at exactly the same
points in time. When dealing with sources such as samplers, A/D converters, DAT machines, and
CD transports, it may not be possible to synchronize these pieces of gear so that they are locked to
the ADAT. In this case, you should engage the z-8.8a's sample rate conversion (SRC) by pressing
the synchronize button. The synchronize LED will light up to let you know the SRC is engaged.
Because the following point is so important, we will highlight it:
When the SRC is engaged, the z-8.8a will use the ADAT Optical signal that is being sent to the
S/PDIF destinations as a clock reference. That is, the ADAT signal appearing in the far-right
(position 8) of the routing pattern display is used as a clock master for the sample rate
conversion.
If you know for a fact that all of the S/PDIF sources are at exactly the right sample rate and are
synchronous with the ADAT Optical source that feeds destination 8, then you may disengage the
SRC. This guarantees that you are making a bit-for-bit identical transfer.
You will notice that the S/PDIF channels are labeled 8A, 8B, 8C, and 8D. The A, B, C, and D refer
to the four S/PDIF channel pairs for channel 8. When these channels are transferred to ADAT,
you will find that channel pair A transfers to channels 1/2 of the ADAT, B to 3/4, C to 5/6, and D
to 7/8. The same thing happens in reverse; that is, 1/2 from the ADAT go to A, 3/4 go to B, 5/6 go
to C, and 7/8 go to D.
Specifications
Inputs: TORX176 plastic fiber (7X), transformer-isolated coaxial (4X)
Outputs: TOTX176 plastic fiber (7X), transformer-isolated coaxial(4X)
Coaxial input & output impedance: 75
Ω
Coaxial output signal level: 1 volt pp
Input/output resolution: 24 bits maximum
S/PDIF sample rate range: 32 kHz - 96 kHz
Lightpipe sample rate range: 44.1 kHz - 48 kHz
Sample rate conversion performance: better than -115 dB THD+N, 120 dB dynamic range
Dimensions:
Line voltage: 110/220 VAC
Safety Precautions
To reduce the risk of electric shock, do not remove the cover. There are no user-serviceable parts
inside. Refer service to qualified personnel.
The unit should be situated so that its location does not interfere with its proper ventilation. It
should be kept away from heat sources and care should be taken so that liquids are not spilled into
the enclosure through openings.