Philips EM3E, Service Manual, Page: 56 / 120

Circuit Descriptions and Abbreviation List GB 108 EM3E 9.
9.13.2 NexTView
NexTView allows the user to display a program guide on the
TV screen, that contains extensive information for each
program (only when supported by the programs provider).
This information can be displayed in a number of different
summaries:
•
DAY: The daily summary shows, from the current
moment, the program schedule for several stations for a
short time ahead.
• CHANNEL: The channel summary shows the program
schedule for one station.
• THEME: The theme summary shows, for each theme,
the program schedule of the various stations. These
themes consist of sport, film, culture, etc. and is
determined from the station side.
NexTView does not have to restrict itself to information about
the station that is being viewed, but also offers information
about other stations. In the various summaries 3 different
commands can be given for the various program overviews.
These commands appear as follows:
•
WATCH: The set immediately switches over to the
station concerned.
• REMINDER: The start time and date and the station of
the program concerned is stored in the TV reminder list.
The TV will give an OSD-message with the program
information, or switch on the set at the correct moment
(provided the set is in Standby) and tune to the station
concerned.
• RECORD: The timer of the video recorder with ‘Easylink
Plus’ is programmed with the data of the program
concerned. There has to be a video recorder (with
Easylink Plus) connected to SCART2 otherwise the
‘RECORD’ function will not be highlighted. The
connection is via pin 10 from SCART. This means that it
has to be a full SCART or at least pin 10 has to be wired.
In order to be able to realise NexTView, two teletext type data
flows, Data stream 1 and 2, are transmitted with various sub-
code pages of information. This data flow can transport
limited information (max. 40 pages). Data stream 1 is quick
repeating with a repetition time of approximately 20 to 30
seconds. However, Data stream 2 has a much longer
repetition time of approximately half an hour and has a large
transport capacity.
•
Data stream 1 contains information of the station that is
being viewed.
• Data stream 2 contains up to one week of advance
information from various stations that are covered by the
provider.
9.14 CRT / SCAVEM / Rotation (diagram F)
9.14.1 RGB Amplifiers
On the CRT panel, the RGB amplifier (TDA6108, IC7307) is
located. Via the outputs 7, 8 and 9 the cathodes of the picture
tube are driven.
The supply voltage for the amplifier is 200 V and is derived
from the LOT.
9.14.2 SCAVEM
The SCAn VElocity Modulation (SCAVEM) circuitry is
implemented in the layout of the picture tube panel. It is thus
not an extra module. This circuit influences the horizontal
deflection as a function of the picture content. In an ideal
square wave, the sides are limited in slope due to a limited
bandwidth (5 MHz).
Principle
SCAVEM will improve the slope as follows:
At a positive slope, a SCAVEM current is generated which
supports the deflection current. At the first half of the slope,
the spot is accelerated and the picture is darker. At the
second half of the slope, the spot is delayed and the slope
becomes steeper.
At the end of the slope, the SCAVEM-current decays to zero
and the spot is at the original position. An overshoot occurs
which improves the impression of sharpness.
At the negative slope, the SCAVEM-current counteracts the
deflection. During the first half of the slope, the spot is
delayed, the slope becomes steeper. During the second half
the spot accelerates, the SCAVEM-current is zero at the end
of the slope.
Implementation
Via the three resistors R33358, R33359 and R3360, Red,
Green and Blue are added together, buffered and offered to
the emitter of TS7300. On the collector of this transistor,
configured in a common base, the sum of these 3 signals is
obtained. Via the emitter follower formed with TS7301, this
signal is conveyed to the differentiator C2330, R3324 and
R3318. Only the high frequencies are differentiated (small
RC-time).
The positive and negative pulses of this signal drive
respectively TS7303 and TS7302 into conductivity. The DC
setting of the output stage is set by R3304, R3308, R3316
and R3319. The working voltage of the transistors is settled
at half the supply voltage.
At the positive section of the pulse, the current flows through
R3318, C2307, the SCAVEM-coil and TS7303. At the
negative section of the pulse, the current flows through
R3318, C2309, the SCAVEM-coil and TS7302.
9.14.3 Rotation
In sets with a rotation coil (wide screen sets), the amount of
frame rotation is adjusted with the DAC-output of the HOP
(see also 'Vertical Deflection').
9.15 Software Related Features
Following features are described:
•
Auto TV
• ‘Switch On’ Behaviour
9.15.1 AutoTV
The AutoTV (or 'Automatic Picture Control' or 'Active
Control') aims at giving the customer the best possible
picture performance at any time. Therefor it does real time
processing of the video signal and as a result, it decides to
adapt several video parameters throughout the whole
chassis.
The AutoTV feature integrates traditional picture
performance, AutoTV functionality and 'smart controls' in
order to come to a kind of 'super smart' TV. It can be
subdivided in:
•
Auto Noise Reduction. This algorithm measures the
amount of noise in the incoming video signal (this is done
by the LIMERIC part of the PICNIC). As a result of this
measurement, the amount of noise in the picture is
corrected, starting from that noise level which is
annoying for the customer. Which parameters exactly
can be used is depending on the hardware.
• Auto Sharpness. This algorithm measures the amount
of sharpness via the bandwidth of the incoming video
signal and adapts the peaking frequency in the PICNIC
according to this info. If the 'sharpness meter' sees the
video content as 'sharp', high frequency peaking will be
used. On the other hand, if the picture content is seen as
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