Artificial Generation Of Harmonics - Behringer ULTRA-DYNE PRO DSP9024 User Manual

Typ
Connection
Mode
Impedance
Level
Clock accuracy
Jitter
Unfortunately, the professional standard was soon watered down, as the design of many units didn't provide
enough room for XLR connectors. Instead, stereo jacks, miniature jacks and special adapters for sub-D
connectors were used.
In addition to the electrical differences, the formats also have a slightly different structure. The audio informa-
tion occupies the same position in the data stream, making the two formats compatible in principle. The
differences between the two standards can be found in the information blocks. Table 4.2 shows a section of
the professional format data structure generally used in AES/EBU connections.
Byte
0 P/C
1
2
3
4 Audio reference
5
Table 4.3 shows the corresponding data of the consumer format commonly used for S/PDIF connections. The
first bit serves to identify the following data as professional or consumer format.
Byte
0 P/C
1
2
3
As can be seen, there are major differences in the significance of the following bits between the two formats. If
a device such as a commercially available DAT recorder only has a S/PDIF input, the device will normally only
understand that format. Generally, it will switch off when receiving professional-format data. The reason is
simple: As the illustrations show, a signal coded in professional format would lead to copy-protection and
emphasis errors in a device only capable of processing the consumer format!
As was already the case with the connectors, this point is often not immediately obvious. Many units do not
switch off, others can process both formats despite having only a single connector type, and still others are
simply faulty designs which refuse to work properly even when receiving correct ID data.
The ULTRA-DYNE PRO can be equipped with an AES/EBU interface as an option.

4.3 Artificial generation of harmonics

In the year 1955, the American Charles D. Lindridge invented the Exciter, a unit that "excites" upper harmon-
ics, and presented a unit for "improving the sound of music and speech". He enriched signal sources with
artificially generated upper harmonics and found that sound quality, transparency and the perceived posi-
ULTRA-DYNE PRO DSP9024
AES / EBU
XLR
Balanced
110 Ohm
0,2 V bis 5 Vpp
Not specified
± 20 ns
Tab. 4.1: Important data for the AES and IEC specifications
0 1 2
Audio?
Channel Mode
Use of AUX bits
Reserved for description of multichannel recording
Tab. 4.2: Professional format (AES/EBU) ID data
0 1 2
Audio? Copy
Category code
Source number
Sampling frequency
Tab. 4.3: Consumer format (S/PDIF) ID data
4. TECHNICAL BACKGROUND
IEC 958 (S/PDIF)
Cinch / Optisch
Unbalanced
75 Ohm
0,2 V bis 0,5 V pp
I: ± 50 ppm II: 0,1 % III: Variable Pitch
Not specified
Bit
3 4
Emphasis Locked
Use of User bits
Length of audio sample
Reserved
Reserved
Bit
3 4
Emphasis
Channel number
Clock accuracy
5 6 7
Sampl. Freq.
Reserved
5 6 7
Mode
Gen.St.
Reserved
37