Sony BVP-570, Maintenance Manual

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2-5 (E)
BVP-570
2-4. Circuit Description
Circuit description for the camera and CCD unit is described here. The CCD unit OHB-450/451/455WS/
550/550W series for the BVP-570 is available separately. The camera portion except the CCD unit is
called as BVP, and OHB-450/451/455WS/550/550W series or CCD unit for the BVP-570WSPK is called
as OHB in this section.
(1) CCD Drive System (OHB)
TG-159/195 board
The TG-159/195 outputs the pulses for driving the CCD to the DR-271 board and outputs the pulses for
sampling the CCD output to the PA-181/213 board.
The driving pulses are synchronized with the HD and VD pulses input from the BVP and are output.
Pulses are generated from the VCO clock (36 MHz) of the board. The clocks for the digital processing
circuit (36 MHz, 18 MHz)are also output to the BVP.
CCD V-sub voltage, white shading data and so on are also stored in the EEPROM of the TG-159/195
board.
DR-271 board
The DR-271 board converts the pulses from the TG-159/195 board to directly drive the CCD. The
converted pulses are transmitted to the CCD via the BI-91(R)/91(G)/91(B) board respectively. The board
also has a circuit which makes + 29 V from + 15 V for the V-sub voltage. Furthermore, the board also has
an interface circuit for the optical filter.
BI-91(R)/91(G)/91(B) board
The CCDs are mounted on the BI-91(R)/91(G) /91(B) boards. These boards supply the driving pulses and
control voltages to the CCD.
The signals output from the CCD are sent to the PA-181/213 board via the emitter follower.
PA-181/213 board
The PA-181/213 board extracts video signals from the CCD signals output from the BI-91(R) /91(G)/
91(B) boards by a correlated double sampling circuit, and amplifies the R and G signals by one time, and
the B signal by three times. The resultant signals are output to the VA-163A board of the BVP.
DR-302 board (OHB-451/451P only)
The DR-302 is a driving board for one optical filter disk, which motor-drives a filter selected by the RCP
or MSU.
The DR-302 board consists of a motor-drive circuit, and a servo circuit comprised of a selected filter
detection and filter position voltage generation circuits.
2-4. Circuit Description