Decode Box - Prism Sound ADA-8XR Operation Manual

Prism Sound ADA-8XR Multi-channel A/D D/A Converter
Note that more than one source LED can be lit; this might happen when two Digital I/O
Modules are 'cascaded' in Split96 mode to provide all eight inputs, or when the 'Input
Selection Mode' is set to 'Channel', allowing each channel's input to be chosen from more
than one assigned port (see the Firmware Reference). A source LED which is flashing
indicates that a selection has been requested which the ADA-8XR firmware cannot
accomplish, for example a source port may have been assigned which has already been
assigned to the other Path.
The 'Overkiller' LED shows that one or more channels in the Path has its Overkiller
(progressive analogue limiter) switched on. For more information about the operation and
application of the Overkiller, see section 7.5.
The 'Mic' and '+48V' LEDs only apply to Analogue Input Modules with a mic-pre facility, and
indicate that one or more channels in the Path have the mic-pre selected, and the phantom
power turned on respectively.

5.1.2 Decode box

The Decode box indicates the wordlength of the Path's digital inputs (if digital inputs are
assigned), and also any decode algorithms which are in use. The Decode box's Access
button attracts the attention of the Menu panel immediately to the small group of menus that
control the available decoding algorithms. For details of these menus, see the Firmware
Reference.
The 'MR-X' LED shows that the input port is being decoded from the Prism Sound MR-X
format, which is a word-mapping scheme whereby, for example, a multi-channel digital
recorder can be used to record longer wordlengths and/or higher sample rates than its native
format by sacrificing tracks. 'MR-X
channels) with a maximum 16-bit wordlength, whereas 'MR-X
where less track sacrificing results. The '[20b]' LED shows that 'MR-X
place, whereas the 'MR-X' LED without the '[20b]' LED shows 'MR-X
Sound MR-X encoding scheme is described in detail in section 7.4.
The 'DRE' LED shows that one or more of the input channels are being decoded from the
Prism Sound DRE (Dynamic Range Enhancement) format, which is a coding scheme to allow
extended wordlengths to be recorded on a medium (or passed down a digital channel)
WITHOUT sacrificing tracks. 'DRE
channels) with a maximum 16-bit wordlength, whereas 'DRE
however, that the decoding algorithm is common for DRE
necessary to distinguish which is to be decoded. The Prism Sound DRE encoding scheme is
described in detail in section 7.4.
The green LEDs at the left-hand side of the box show the effective input wordlength of the
input channels. Note that the wordlength AFTER any decoding is indicated, i.e. a 24-bit
signal being recovered from a 16-bit MR-X tape is indicated as 24-bits. The indication is
made by detecting how many of the low-order data bits are held at zero, rather than by any
other means. Note that multiple wordlength LEDs may be lit if different input wordlengths
occur simultaneously on different channels.
© Prism Media Products Limited, 2001-2004
' is the variant of this format for recorders (or data
16
' is the variant of this format for recorders (or data
16
16
Operation Manual - Revision 1.00
' is used for 20-bit media
20
' decoding is taking
20
' decoding. The Prism
16
' is used for 20-bit media. Note,
20
and DRE data, so it is not
20
Page 1.16