RME Audio HDSPe RayDAT, User Manual

Page: 78 / 84

78
User's Guide HDSPe RayDAT
© RME
27.5 QS
– Quad Speed
In earlier times the transmission of 192 kHz had not been possible via Single Wire, so once
again sample multiplexing was used: instead of two channels, one AES line transmits only one
half of a channel. A transmission of one channel requires two AES/EBU lines, stereo requires
even four. This transmission mode is being called
Quad Wire in the professional studio world
and is also known as S/MUX4 in connection with the ADAT format.
In 48K Frame Quad Speed mode, the HDSPe RayDAT distributes the data of one channel to
four consecutive ADAT channels. This reduces the number of channels from 32 to 8. The Ray-
DAT spreads two channel's data to eight channels according to the following table:
Original 1 2
QS Signal
Port 1
ADAT1
2
ADAT1
3
ADAT1
4
ADAT1
5
ADAT1
6
ADAT1
7
ADAT1
8
ADAT1
As the transmission of double rate signals is done at standard sample rate (Single Speed), the
ADAT outputs still deliver 44.1 kHz or 48 kHz.
The SPDIF and AES/EBU I/Os of the RayDAT operate in Single Wire mode only.
27.6 SteadyClock
The SteadyClock FS technology of the HDSPe RayDAT guarantees an excellent performance in
all clock modes. Thanks to a highly efficient jitter suppression, refreshes and cleans up any
clock signal, and provides it as reference clock at the word clock output.
SteadyClock has been developed 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 reso-
lution of 125 MHz within the format.
The input sources of the HDSPe Ray-
DAT, ADAT, AES/EBU, word, Video
and LTC gain a lot from SteadyClock
as well. In fact, extracting a low jitter
clock from LTC is not possible without
a SteadyClock similar technique at all.
The screenshot to the right shows an
extremely jittery AES/EBU signal of
about 50 ns jitter (top graph, yellow).
Again SteadyClock provides an ex-
treme clean-up. The filtered clock
shows less than 1 ns jitter (lower graph,
blue).
The cleaned and jitter-freed signal can be used as reference clock for any application. The sig-
nal processed by SteadyClock is not only used internally, but also available at all outputs of the
HDSPe RayDAT.