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DXD/LTC User Manual (rev 2.10)
4. Time Code Menus
4.1 SMPTE 2059 Setup (Menu 8.1)
4.1.1 DAILY JAM TIME:
The Daily Jam is a process where the time code generator realigns precisely with the epoch (midnight
on Jan 1, 1970). This process occurs everyday, at the same time, as set in the DAILY JAM TIME field.
The value entered in the DAILY JAM TIME field is the amount of time after midnight, local time, at
which the daily jam will occur.
Adjustments can be made in 10 minutes increments. Default value is 01 Hrs 00 Min, i.e. 1:00AM,
local time.
4.1.2 JAM TIMES RECALCULATE:
Pressing the ENTER key while “Press Enter to Jam” is selected will cause the DXD to recalculate both Jam Times, the time of the Previous
Daily Jam Event and the time of the Next Daily Jam Event.
For time code, the Previous Daily Jam Event is the generator’s anchor point, until the Next Daily Jam Event. When the local time is too
close to the set Daily Jam Time, a manual change will not occur until the next day. By forcing the DXD to recalculate both jam times
manually, the operator has the option to make an immediate change.
NOTES ON DAILY JAM AND NTSC DRIFT:
The Daily Jam will occur at the set time, no matter what format time code is generated. With 24, 25 or 30 ND time code, there will be
no correction as each second is divided in a whole number of frames. However, that is not the case with 29.97. Even when using Drop
Frame (i.e. skipping 2 frames on every minute not divisible by 10) a correction will be required as 29.97 time code is actually running
at 29.97002997002… fps (30 x (1000/1001). For that reason, when maintaining a time code sequence longer than 24 hours, it
should be jammed to local time daily. Per ST2059-1, a Daily Jam is usually set to occur at an operationally convenient time, typically
during the early morning hours in local time. Default value on the DXD is set at 1:00AM.
4.2 TC Generator 1 (Menu 8.2)
4.2.1 TCG 1 SETTINGS (MENU 8.2.1)
4.2.1.1 OPERATING MODE
The choices for Operating Mode are Time-Of-Day or Simple/Run/Stop/Cue.
•
Time-Of-Day
means that the time code addresses will match the time-of-day, or System Time in the case of the DXD,
expressed in Local Time. This generator can be stopped and restarted. However, when restarted, the generator will jump to
the current time of day.
•
Simple Run/Stop/Cue
is like a traditional time code generator. A Cue Point can be set in menu 8.2.2. Unlike the TOD
generator, when restarting, the generator will resume where it stopped, unless of course the CUE command was initiated
before START.
4.2.1.2 TIME CODE RATE/COUNT
This field has the following choices:
•23.976/24
•24/24
•25/25
•29.97/DF
•29.97/NDF
•30/DF
•30/NDF
