4-2
DVW-250/250P
Playback System
The PB RF signal sent from the drum is converted into 4-
channel serial PB data by the PB equalizer and viterbi
decoder on the EQ-54 board.
Using a data rate converter, the 4-channel serial PB data on
the DPR-62 board is converted into 2-channel parallel PB
data whose clock frequency is two times the normal.
Next, inner correction is performed using an inner ECC
decoder, and the converted data is separated to video data
and audio data.
The video data is outer-corrected using an outer ECC
decoder and converted into the parallel video data of the
former data rate using a bit rate reduction decoder. If an
error that cannot be corrected using the ECC decoder
exists, the error correction is performed. The video data
output from the bit rate reduction decoder is converted into
a composite parallel signal using a composite encoder. The
converted signal is then converted into an analog compos-
ite video signal and SDI video signal.
The audio data is error-corrected after it is outer-corrected.
The resultant data is passed through an audio processor,
then converted into an analog audio signal and SDI audio
signal.
The video output signal consists of a composite video
signal and SDI video signal, and the audio output signal
consists of an analog audio signal and SDI audio signal.
The monitor output signal consists of a composite video
signal and analog audio signal and is sent to the camera
and RFU as well as headphones and an earphone.
System Control and Servo Systems
The system control system operates the front panel and
receives the command from the camera and external
equipment so as to control and manage this unit.
This unit has two internal CPUs for system control and
servo control and exchanges data between the system
control and servo control by an SV/SY communication IC.
A 32-bit CPU with an operation clock of 10 MHz is used
as the system control CPU, and a 16-bit CPU with an
operation clock of 10 MHz is used as the servo control
CPU. Both the 32-bit CPU and 16-bit CPU incorporate
peripheral equipment to some degree, so they reduce the
number of external circuits.
The system control CPU controls the time code (reader and
generator), character generator, front panel key, liquid-
crystal display, and signal processing system. The system
control CPU also communicates with the camera and other
external equipment.
The servo control CPU receives instructions from the
system control CPU, detects the sensor and FG/PG states,
and controls the drum and motor.
This unit is controlled from external equipment with Sony
9-pin protocol or ISR.
