DCS 1.0x User Manual
dCS Verona User Manual
Manual for Software Issue 1.0x
dCS Ltd
September 2004
Manual filename: Verona Manual v1.0x.doc
Page 24
email: more@dcsltd.co.uk
English version
web-site: www.dcsltd.co.uk
V
ERONA
T
ECHNICAL
I
NFORMATION
Digital Interface Specifications
Wordclock Outputs
/ Ext. Ref. Input
/ Ext. Ref. Input
Ext Ref Input
Outputs
Type
Single ended,
ground referred
Impedance
75
25
Ω
Level (unloaded)
TTL
TTL
Connector
BNC
BNC x 5
Table 1 –Wordclock Output / Ext Ref Input Electrical Characteristics
SPDIF
Outputs
Type
Single ended,
ground referred
Impedance
75
Ω
Level (unloaded)
1.0
V pk-pk
Connector
RCA Phono x 3
Table 2 – SPDIF Output Electrical Characteristics
Output Frequencies
44.1kHz or 48kHz on all Word Clock Outputs.
44.1kS/s or 48kS/s clock on all SPDIF Outputs.
44.1kS/s or 48kS/s clock on all SPDIF Outputs.
Clocking
The sample clock quality significantly determines the output performance of the
system. The highest quality clocks that are available are crystals, so we use
these. Verona uses a pair of pre-aged, specially selected voltage controlled
crystal oscillators (VCXO’s) as clock sources. Each unit is individually calibrated
over a wide temperature range for best accuracy.
system. The highest quality clocks that are available are crystals, so we use
these. Verona uses a pair of pre-aged, specially selected voltage controlled
crystal oscillators (VCXO’s) as clock sources. Each unit is individually calibrated
over a wide temperature range for best accuracy.
When slaving to
Ext Ref In
, the VCXO is synchronised to the clock signal
extracted from the input by a phase locked loop (PLL). This PLL is of a special
narrow bandwidth type, that provides a significant degree of "clock cleaning”.
The PLL is also very robust, and will lock to very poor signals if necessary.
narrow bandwidth type, that provides a significant degree of "clock cleaning”.
The PLL is also very robust, and will lock to very poor signals if necessary.
Accuracy
Typically
±
0.1 parts per million when shipped
Better than
±
1 part per million within 6 months of shipping
Synchronising to
Ext Ref In
x
The unit will slave to the following clock signals on the
Ext Ref In
connector:
•
Word Clocks at 32, 44.1, 48, 88.2 or 96kHz (set the
Couple
menu to
TTL
).
•
Reference clocks at 10MHz, such as those produced by GPS receivers or
atomic clocks (set the
Couple
menu to
Bipolar
).
Pull-in range
±
300 parts per million about nominal frequency
Lock-in time
< 12 seconds for most situations