Philips Colour Television Service Manual page 89

Circuit Descriptions, List of Abbreviations, and IC Data Sheets
Component video from the YPbPr input is fed to U1201, switch.
The YPbPr input on the ATSC module can be 480i, 480p, 720p,
or 1080i. The A/D, U201 shares a 16bit bus with the HDMI
receiver. Only the Philips version has the HDMI input. The
Customer selected signal is fed to U201, the ATSC processor.
The ATSC processor enhances and rescales the signals from
these inputs. The ATSC tuner, U701, is fed to the IF section,
U703, and then to filters U704 and U703. The ATSC processor
can decode either 8VSB terrestrial, 64QAM, or 256QAM
signals.
The output of the ATSC processor is fed to the POD processor
IC. Most of the POD processing circuit is not present since this
set does not have that feature. Two memory ICs, U502 and
U503 stores the picture information while the video is being
processed. The analog YPbPr 1080i signals are output to the
HOP module.
9.3.12 SSM HOP Buffer Amplifiers
Figure 9-19 SSM YUV-buffers
The Y-SSB, U-SSB, and V-SSB signals are fed to buffer
amplifiers, located on the SSM. Transistors 7806 and 7807
buffer the Y signal. The U signal is buffered and inverted by
transistors 7810 and 7811. The V signal is buffered and
inverted by transistors 7808 and 7809. The YUV signal is then
fed to the HOP panel via connector 1250.
9.3.13 HOP RGB/YUV Switching
1151
3
From
ATSC
1
module
5
Figure 9-20 RGB/YUV switching
E_15000_086.eps
181004
F_15120_041.eps
090805
DPTV585 AA
The input to the HOP panel can be RGB or YPbPr via the cinch
connectors. The RGB or YPbPr signal can be either 480p,
720p progressive scan or 480i, 1080i interlaced.
IC7210 selects between the output of the ATSC panel and the
YUV signal from the SSM.
The switch is controlled by the VS2 switching signal.
9.3.14 HOP Signal Processing
The Y/G, B/Pb, and R/Pr signals are fed to their respective
sharpness controls. If the input is a YUV signal, the Y signal is
fed to pin 28 of 7600. The U and V signals are fed to the Tint
Control circuit and then to Pins 27 and 26 of 7600. If the input
is RGB, the signals are fed to Pins 31, 32, and 30 of 7600 to an
RGB to YUV converter. When RGB input is used, there is no
Tint control available for the signal.
The input selector switch in 7600 selects between the YUV on
Pins 28, 27, and 26 or the output of the internal RGB/YUV
converter. The signal is fed to the RGB insertion circuits where
the OSD is inserted. The signal is then fed to a White Point
circuit and then to the Output Amplifier. The White Point and
Output Amplifier have the Drive controls and Cut-off controls.
Input from the ABL line on Pins 43 makes adjustments in the
brightness levels to adjust for changes in beam current. The
AKB pulses from the CRTs are fed to pin 44 to the Cathode
Calibration circuit. The Cathode Calibration circuit adjusts the
Cut-off levels of the CRTs to maintain the correct grey scale
tracking. When the set is first turned "on", a calibration pulse is
output on the RGB lines. The Cathode Calibration circuit
monitors this pulse on the AKB line to set the Black level and
the maximum drive voltage for the cathode. Once the
Calibration has taken place, the Output Amplifiers switches to
the RGB drive signal as the output.
Horizontal and Vertical Sync is fed to 7600 on Pins 23 and 24.
IC 7600 processes the sync to provide the geometry for the
picture. Horizontal drive is output to the sweep circuit on pin 8.
Vertical drive is output on Pins 1 and 2. East West drive is
output on pin 3. Sandcastle (SCO) is output on pin 9. Horizontal
Feedback (HFB) from the sweep circuit is fed into the Phase
Loop to phase correct the Horizontal drive.
IC 7600 is controlled by the microprocessor via the I2C buss on
Pins 10 and 11. Geometry and Drive settings are stored in the
Memory IC located on the HOP panel.
9. EN 89