DCD-8 User Manual
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DCD-8 User Manual
12.1. DOMAIN B VSO
Domain B can be independently in VSO mode.
However, if set to “Use REF A” and if domain A is in VSO mode, then domain B will track
the VSO speed setting of domain A. So A could be 48000, and B 44100, and both
VSO’d up 100 cents by adjusting the REF A VSO setting. (NOTE: the long term relative
accuracy of the two rates is considerably reduced in this mode.)
12.2. VSO & THE VSG-4 OPTION CARD
• VIDEO OUT: ENABLE SD ONLY:
With the VSG-4 option card installed, when SD only is enabled (menu 52), VSO opera-
tion in domain A is prohibited as the SD video cannot track the varying wordclock rate.
The VSO option will not appear in menu 02.
To eliminate this conflict, if the video outputs are not being used, switch off the video op-
tion. For more on this, please refer to the VSG-4 User’s Manual.
• VIDEO OUT: ENABLE HD & SD:
When the HD and SD outputs are enabled and the VSG-4 has taken over REF B, domain
A VSO is allowed.
NOTE: If the HD Ref has been set to ‘Use REF A’ in menu 52, the video output will track
the Ref A rate prior to VSO. As a result, the video sync “edge” alignment to the word
clock will be turned off (see VSG-4 User Manual).
13. Source Reference Failure Options
In the event of failure of the external reference, the DCD-8 has 2 different ways of insuring
that the WC output remains safely uninterrupted.
13.1. MAIN REFERENCE FAILURE WITH NO ALTERNATE REFERENCE SET
If no alternate reference was set in menu 03, the DCD-8 holds the last known frequency
and displays “HOLDING” as a lock status.
If a signal is still present at the main reference input, the DCD-8 automatically attempts to
lock to it again. If it succeeds, it goes through the normal ‘Locked’ sequence; if not, it contin-
ues holding and attempts to Lock to the main reference again.
If no signal is present at the main reference input, the DCD-8 will remain in ‘HOLDING’
mode indefinitely.
13.2. MAIN REFERENCE FAILURE WITH AN ALTERNATE REFERENCE SET
If an alternate reference was set in menu 03, the DCD-8 goes into the following cycle:
• Step 1: - the PLL switches to the Alternate Reference
- the generator goes in HOLDING mode, holding the last known frequency.
• Step 2: After about 2 seconds, the generator switches smoothly to the alternate reference.
During Step 1, the Lock status on the LCD display indicates “HOLDING”.
During Step 2, the lock status goes from ‘LOCKED --” to “LOCKED” as it reaches full lock.
In the event of failure of the Alternate Reference, the DCD-8 goes back through steps 1 and
2, but this time, Internal Crystal is used as the new reference.
11.4 OFF SPEED INDICATION WITH A SET REFERENCE
When the reference is detected to be off speed by more than 1.5%, the DCD-8 alerts the
user as follows. The main display alternates between the normal LOCKED status and the
OFF SPEED indication, staying about 2 seconds on each one. The measured reference
frequency is shown under the words ‘Off Speed’ for comparison with the expected rate,
shown under the reference.
Here is an example of the Off Speed indication for Ref A WC1.
For comparison, here is another example for Ref A Video, off speed:
11.5 HOW DOES IT ALL WORK?
To help To help understand how these different modes interact, let’s take a look at a few examples.
Note: 48.003 is only used in these examples to illustrate that the DCD-8, when locked to
the reference, will track small variations. 44.100 is used to illustrate when a completely dif-
ferent rate is supplied or intended.s.
• Ref: LEARN & Rate: AUTO
The DCD-8 LEARNS the incoming rate and the
48.003k in = 48.003k out
output rate matches the input. In this case, no rate
44.1k in = 44.1k out
needs to be programmed.
• Ref: LEARN & Rate: SET (48k)
The DCD-8 LEARNS the incoming rate. Adding
48.003k in = 48.003k out
SET assigns the nominal output rate.
44.1k in = 48k out
• Ref: SET (48k) & Rate: AUTO
The DCD-8 SETS the expected input rate.
48.003k in = 48.003K out
With AUTO, the rate mirrors the reference.
44.1k in = 44.1k out (‘Off Speed’)
OFF SPEED indicates the reference is not 48K.
• Ref: SET (48k) & Rate: SET (44.1k)
The DCD-8 SETS the expected input rate and the
48.003k in = 44.103k out
expected output rate. An inputt rate different than
44.1k in = 40.517k out (‘Off Speed’)
what was SET provides a proportionate speed change
12. VSO
VSO is selected in the Reference menus (02 for domain A and 22 for domain B). In the main
display, when domain A is in VSO mode and domain B is following A:
NOTE: With VSO activated, the displayed frequencies on the right side of the LCD are not
the resultant frequencies but rather the base frequency, prior to VSO being applied.
