User`s guide
User's Guide TEB
8
8. Double Speed
Sample rates above 48 kHz were not always taken for granted, and are still not widely used
because of the CD format (44.1 kHz) dominating everything. Before 1998 there were no re-
ceiver/transmitter circuits available that could receive or transmit more than 48 kHz. Therefore
a work-around was used: instead of two channels, one AES line only carries one channel, of
which the odd and even samples are being distributed to the former left and right channels. By
this, you get the double amount of data, i. e. also double sample rate. Of course in order to
transmit a stereo signal two AES/EBU ports are necessary then.
This transmission mode is being called Double Wire in the professional studio world, and is also
known as S/MUX in connection with the ADAT format. The DTRS recorder DA-98HR by Tas-
cam also uses this technique, which is called Dual Line here.
Not before February 1998, Crystal shipped the first 'single wire' receiver/transmitters that could
also work with double sample rate. It was then possible to transmit two channels of 96 kHz data
via one AES/EBU port.
Because the ADAT interface does not allow for sampling frequencies above 48 kHz (a limita-
tion of the interface hardware), the Hammerfall and HDSP 9652 automatically use a method
called Sample Spli. One channel's data is distributed to two channels according to the following
table:
Original 1 2 3 4
DS Signal 1/2 3/4 5/6 7/8
As the transmission of double rate signals is done at standard sample rate (Single Speed) the
word clock output still delivers 44.1 kHz or 48 kHz.
The wordclock output as well as all ADAT and TDIF ports always operates in Single Speed
mode only. At 96 kHz, the word clock output will therefore be a 48 kHz signal.
The TDIF interface of the TDIF Expansion Board also supports the 'Double Wire' technique.
This allows a recording with up to 96 kHz at halfed track numbers with every (!) DTRS device.
9. Connector Pinout D-sub
The 25 pin D-sub connector is wired according to TDIF-1, version 1.1:
Signal
Out
1/2
Out
3/4
Out
5/6
Out
7/8
Out
LRCK
Out
EMPH
Out
FS0
Out
FS1
D-sub
1 2 3 4 5 18 6 19
Signal
In
FS1
In
FS0
In
EMPH
In
LRCK
In
7/8
In
5/6
In
3/4
In
1/2
D-sub
20 8 21 9 10 11 12 13
GND is connected to pins 7, 14, 15, 16, 17, 22, 23, 24, 25.