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Cantar-X User Manual v2.44 (r14) 2013 March 21
p.14
p.14
Cantar as a master-clock
As soon as the
int c
icon stops blinking, Cantar starts gener-
ating timecode kept in its 'Sync Clock', a 1ppm 'Temperature
Compensated (X)crystal Oscillator' (TCXO) clock accurate to
±one frame in nine hours. This high accuracy 'Sync Clock'
makes Cantar
the
TC reference on set.
To continuously sync equipment through cables and trans-
mitters, or to quickly jam-sync a camera, a Cantar or a
GMT*, turn 'ON' the LTC generator in AUDIO/TC.17 'Ltc
Gen Out'.
* Aaton GMTs are low power, high accuracy timekeepers
to be attached to cameras and digi-slates.
Do not power down a master-clock!
Being on a job on which the Free-Run time-of-day TC is
the essence (AatonCode camera, Digital camera with
GMT reference generator, smart digi-slate), never power
down Cantar during the workday to avoid the loss of its
1 ppm reference time! While the internal HD is in sleep
mode the total power consumption is a mere 270mA! Set
TECHSET.16 'HD Pwr Dwn' to '
After 5min
', to have the HD
sleep five minutes after STOP. If you still want to power
down Cantar at lunch time, the blinking
int
c
icon at power
up will remind you to re-initialize all other timekeeping
machines on the set.
Method 2
'int c'
internal
Record-Run
driving clock
Go to AUDIO/TC.20 'RecRunTc In', [ok]: 01:00:00 is pro-
posed as the first TC of the day (it can be modified). From
now on, at the beginning of each audio file Cantar will
stamp a start-TC incremented by two seconds later than the
preceding take's end-TC. This clocking, called Record-Run,
produces audio files which appear as if they have been
recorded in continuity.
If for some reason Cantar is turned 'OFF', the Record-Run
TC must be initialized again. To prevent any TC overlap,
Cantar proposes to start on the next hour integer, e.g. if the
last recorded take has been closed at 01:34:15, the next
start-TC proposed to the Operator will be 02:00:00.
The Cantar Record-Run mode lets you use the pre-record
buffer without creating TC overlaps. For example, if the
preceding take ends at 01:45:00, and the pre-record buf-
fer is set at thirteen seconds, the next audio file will start at
01:45:02
(two second gap), but the LTC emitted by the generator to
the camera when hitting REC will be 01:45:15.
While Cantar is in Record-Run mode, its reference TC must
be continuously sent to all cameras on the set by wire or
RF.
note:
in TEST and PPR, the LTC output is frozen on the end-
TC value, it can thus be used as a master TC to start and
stop another Cantar (see
Record by LTC
, p.21).
Method 3
'int c' internal clock,
AutoSlate
on clapsticks
If the same TC is not running in Cantar and cameras, the
only way to sync pictures and audio is to use clapsticks; for-
get digi-slates, they have too many drawbacks. The Cantar
AutoSlate sample-accurate clapstick detection function puts
a timecode crown over the simplest piece of wood (p.23).
Method 4
'ext c'
slaved
to an external clock
An externally-slaved Cantar stamps the audio files with the
same TC as the one running in the video camera. This
requires a link from the camera to Cantar.
Set AUDIO/TC.15 'Tc Source' to '
Ext. Clock
';
ext
c
blinks
in the circular screen, meaning that Cantar is waiting to be
slaved to an external LTC, e.g. a video camera.
Cantar,
while set to 'external clock', will only jam when you go to
REC; pressing the [TC jam] button will do nothing.
Cantar is usually in REC before the camera, so it monitors
the Lemo 5/SubD 15 incoming LTC and grabs it when coher-
ent TC is received. That is why
ext
c
keeps blinking until the
camera is up to speed.
Before closing the audio file, Cantar stamps the TC by using
the latest valid timecode so as to eliminate spurious transmis-
sion errors and false camera starts. If there is no external
timecode signal, an '
LTC Not Detected
' warning appears in
the rectangular screen and a phone beep is triggered every
four seconds. The beep is muted during 'w' (wild track)
tagged takes (see
Warning beeps
, p.22). Nevertheless,
the external TC is grabbed if it is received before the take's
end.
note:
external LTC breaks can be used to slave the REC start
and stop (see
Record by LTC
, p.21).
STOP
TIME & SYNC [2]
