4-2
DNW-7/90/90WS
(2) Digital signal system
(DVP-1 (1/2) board, DVP-2 board, and drum
assembly)
.
Signal processing during recording
The parallel video data supplied from the camera is
compressed to a data rate of approximately 1/10 using an
SX encoder after addition of the VITC signal.
The compressed video data is input to the ECC encoder
where an outer ECC is added to the video data and track-
interleaved.
The serial audio data (A/D DATA 1/2 and 3/4) supplied
from the TC-80 board is also input to the ECC encoder
where an outer ECC is added and the audio data is field-
shuffled. The video data and audio data are multiplexed
and inner-ECC-encoded by the ECC encoder.
The resultant data is then sent to the drum as the four-
channel parallel record data.
The Betacam SX Camcorder records the video and audio
signals on magnetic tape in a Betacam SX format.
The Betacam SX Camcorder uses the four rotary heads
which have an azimuth angle in the opposite direction to
each other, and are paired. Every rotation of the drum
records the four helical tracks. Every five rotations of
the drum i.e., the twenty helical tracks record the four
frame data.
*
The Betacam format of the PAL system records the two
frame data with three rotations, i.e., twelve helical tracks.
.
Signal processing during playback
The four-channel parallel PB data sent from the drum is
inner-corrected by the inner ECC decoder.
The parallel PB data is then deinterleaved and sent to the
outer ECC decoder where the video data is outer-
corrected and sent to the SX decoder.
The SX decoder perform the bit rate reduction decoding
of the playback video data so that the original data rate is
restored.
The errors that cannot be corrected by the ECC decoder
are sent to the memory where separate error correction is
performed. This data feedback to the camera block.
Audio data is outer-corrected, error-corrected, then
converted of its clock rate using FIFO memory. The audio
data is sent to the audio data processor in the form of two-
channel serial audio data (CONFI AU 1/2 and 3/4).
The NTSC Betacam SX system is equipped with a five-
field sequence generator which controls the five-field
sequence of audio playback data.
The digital data processing in each IC is performed
under communication with the system control CPU.
.
ES-11 board
The ES-11 board consists of the two major circuit: one is
the circuit which generated the composite signal from
the D/A converted analog component signal supplied
from the DCP-31/1 board, and the other circuit which is
the sync generator circuit generating the various sync
signals for comcorder.
Almost adjustments are performed by electronic control
using setup menu.
The ES-11 board has the sync separator IC and PLL IC
so that the camera block is sync-locked to the external
input video signal supplied from the GENLOCK IN
terminal.
*
1: In DNW-9WS/9WSP/90WS/90WSP, this circuit
operated as follows:
In the 4:3 mode, the digital component signal from
the processor IC is stretched by down-converting
from 18 MHz to 13.5 MHz, then is re-sampled by 18
MHz and is output.
