Time Code Pull-Up / Down - Nagra Seven Operating Instructions Manual

The internal time code generator
The internal time code generator is clocked by the main master clock of the recorder which runs from a crystal
which is a "Stratum III" TCXO that has been artificially aged in an oven to maintain stability. This crystal gives a
guaranteed overall stability better than ± 4.6ppm over a period of 15 years throughout a temperature range
from -20°C to +70°C. The drift due to temperature changes is less than 0.28ppm. This means that the time
code generator of the Nagra Seven would only be re-jammed about once per day, but this may be more
frequent if other equipment is used as a gen lock.
The Time and User portions of the time code can be set either manually, using the main display, or
alternatively from an external time code source, by executing the "Set from External" function (Jam sync). This
operation will instantaneously "grab" the time code on the 5 pin LEMO connector assuming it is a valid format,
and that it is moving (not a stationary time code).
The Stratum III TCXO is precise even if the Nagra Seven is powered down. If upon power up, the Nagra
Note:
Seven does NOT ask for the date and time to be set by the user (Not TC date and time) then this
guarantees that the TC is still accurate as both the TC and RTC use the same crystal.
Time code playback and time code conversion
When a file is played back the time code on the output will be regenerated according to the current time code
settings of the Nagra Seven. Thus a recording originally made with 25 frame TC can be played back at any time
code frame rate by simply changing the settings of the internal generator.

Time code Pull-up / down

The time code system of the Nagra Seven is very powerful and allows a lot of possibilities but should be used
with a lot of care and consideration to avoid unexpected surprises! The notion of "pull-up" is referred to when
talking about the time code in film and television in countries where the NTSC color television system is used
(typically North America and Japan). In these countries, the television frame rate is 29.97 fps and the film rate
is 30 fps. Slowing down a 30 frame film by 0.1% will give a speed of 29.97 fps compatible with the TV system.
This mode of speed alteration implemented in the Nagra Seven allows many possibilities, some of which if
incorrectly used will render the audio unusable.
In the Nagra Seven, the time code rate is slave to the main audio clock. This means that if audio clock runs
slower, then the time code runs slower too.
As an example, if the clock reference of the Nagra VI is set to master -0.1% and the time code rate of the
internal time code generator set to 30 ND, the resulting time code recorded is 29.97 ND (= 30 - 0.1%)
Never use master -0.1% and 29.97 frame rate because this will create an unusable frame rate of 29.94 (29.97
- 0.1%)!!!
Chapter IV 66 March 2014