Sony DTV-01, Manual

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Video processor
RGB Driver
CRT cathodes
HD Input
This input is for an external HDTV (perhaps cable) box that receives and
decodes the HDTV to output component video: Y, R-Y, B-Y (also called Y,
Pb, Pr or Y, Cb, Cr, or Y, U, V, depending upon where you are in the world).
The component video path introduces the component video directly into
the video processor block. The scan width of this picture is a function of
the horizontal frequency.
Video processor
RGB Driver
CRT cathodes
Deflection
The deflection control IC develops signals for:
= Vertical and horizontal deflection (VD & HD)
=
Horizontal pincushion (EW)
=
Picture tilt & horizontal trapezoid correction (VD)
= Focus (V blk)
Vertical and horizontal deflection
The vertical stage is conventional, but the horizontal stage is not. Both the
horizontal driver and output stages have individual PWM stages that sup-
ply regulated B+ voltage to them. The H. output B+ comes from the PWM
stage through the flyback.
Horizontal Pincushion
The horizontal pincushion correction stage compensates for a picture that
is bent inward at the middle of the screen. The E/W correction signal from
the deflection controller is amplified and applied to the yoke at the horizon-
tal output transistor’s collector to correct for insufficient scan.
Picture tilt and horizontal trapezoid correction
Vertical drive (VD) signals not only feed the vertical deflection stage, but
also the picture tilt stage that handles trapezoid correction. A controlled
level of vertical sawtooth (VD) signal is used for trapezoid correction. This
correction signal is mixed with a DC voltage for tilt correction and applied
to the N/S coil suspended about the bell of the picture tube by the yoke.
Focus
There are two focus circuits used in this TV. The dynamic focus circuit
uses horizontal pulses to correct the left and right side picture focus caused
by the flat screen. The dynamic correction voltage is added into the static
(DC) focus voltage that is applied to the picture tube.
The quad focus circuit uses both H & V signals to correct spot shape at
the four corners of the screen. The circuit’s correction voltage is output to
four “QP” coils mounted on a board surrounding the picture tube’s elec-
tron gun.
Power Supply
The power supply consists of:
=
A small 60Hz standby power supply that supplies s5V to the
Main Micro.
= A Main Micro IC that controls the power relay as well as the deflection,
video, and audio stages.
=
A degaussing circuit.
=
Two almost identical converter stages. Converter 2 turns on converter
1. Different voltages are output from each converter to power the TV.
=
A protection circuit to detect excessive voltage and excessive current
in various parts of the TV. The protect circuit also monitors vertical
drive. A failure in the detected areas causes the power ON command
to be removed from AC relay.