Philips FM242 Service Manual page 81

Colour television
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The RC signal (RC_IN) is routed to the OTC, the VGA1
connector, and the RC-out cinch connector.
The signals to (+9V_STBY) and from (+9V_STBY_SW) the
'on'/'off' switch are routed to the PSU board.
9.7
Plasma Display Panel (PDP)
9.7.1
General
The PDP, which is used in the FM242, is a product of SDI
(Samsung Display Industry) . When defect, a new panel must
be ordered, and after receipt, the defective panel must be send
for repair in the packing (flight case) of the new ordered panel.
9.7.2
Operation
Principle
Plasma displays work by applying a voltage between two
transparent display electrodes on the front glass plate of the
display. The electrodes are separated by an MgO dielectric
layer and surrounded by a mixture of neon and xenon gases.
When the voltage reaches the 'firing level', a plasma discharge
occurs on the surface of the dielectric, resulting in the emission
of ultra violet light.
This UV light then excites the phosphor material at the back of
the cell and emits visible light. Each cell or sub-pixel has red,
blue or green phosphor material and three sub-pixels combine
to make up a pixel. The intensity of each colour is controlled by
varying the number and width of voltage pulses applied to the
sub-pixel during a picture frame. This is implemented by
dividing each picture frame into sub-frames.(for 50 Hz-mode
there are 12 sub frames, for the 60 Hz-mode there are 10 sub
frames). During a sub-frame, all cells are first addressed -
those to be lit are pre-charged to a specific address voltage -
then during the display time the display voltage is applied to the
entire screen lighting those that were addressed.
Each sub-frame has a weighting-factor. (Time-entity depends
on size and number of pixels on the screen). This is a purely
digital PWM control mechanism, which is a key advantage as it
eliminates any unnecessary digital to analogue conversions.
Circuit Descriptions and List of Abbreviations
FM242 AA
9.8
Abbreviation list
ADC
AM
AP
AV
B/G
BGA
BTSC
ComPair
CVBS
DAC
DDC
D/K
DFU
DNR
DRAM
DSP
DTS
DVD
DVI-d
EEPROM
EMI
EPLD
EU
EXT
FLASH
FM
FSP
FTV
HP
I
I2C
I2S
ICONN
IF
Interlaced
IR
IRQ
LATAM
LED
L/L'
LS
LVDS
M/N
MOSFET
MPEG
NC
NICAM
NTC
9.
EN 81
Analogue to Digital Converter
Amplitude Modulation
Asia Pacific
External Audio Video
Monochrome TV system. Sound
carrier distance is 5.5 MHz
Ball Grid Array
Broadcast Television Standard
Committee. Multiplex FM stereo sound
system, originating from the USA and
used e.g. in LATAM and AP-NTSC
countries
Computer aided rePair
Composite Video Blanking and
Synchronisation
Digital to Analogue Converter
Display Data Channel (a protocol
based on I2C)
Monochrome TV system. Sound
carrier distance is 6.5 MHz
Direction For Use: description for the
end user
Dynamic Noise Reduction
Dynamic RAM
Digital Signal Processing
Digital Theatre Sound
Digital Versatile Disc
Digital Visual Interface, d = digital only
Electrically Erasable and
Programmable Read Only Memory
Electro Magnetic Interference
Erasable Programmable Logic Device
Europe
External (source), entering the set via
SCART or Cinch
Flash memory
Frequency Modulation
FTV System Protocol
Flat TeleVision
Headphone
Monochrome TV system. Sound
carrier distance is 6.0 MHz
Integrated IC bus
Integrated IC Sound bus
Institutional CONNector
Intermediate Frequency
Scan mode where two fields are used
to form one frame. Each field contains
half the number of the total amount of
lines. The fields are written in 'pairs',
causing line flicker.
Infra Red
Interrupt Request
Latin America
Light Emitting Diode
Monochrome TV system. Sound
carrier distance is 6.5 MHz. L' is Band
I, L is all bands except for Band I
Loudspeaker
Low Voltage Differential Signalling
Monochrome TV system. Sound
carrier distance is 4.5 MHz
Metal Oxide Silicon Field Effect
Transistor, switching device
Motion Pictures Experts Group
Not Connected
Near Instantaneous Compounded
Audio Multiplexing. This is a digital
sound system, mainly used in Europe.
Negative Temperature Coefficient,
non-linear resistor

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