STV2118B Datasheet, PDF (4/25 Pages) STMicroelectronics – BUS CONTROLLED PAL/SECAM/NTSC TV PROCESSOR

STV2118B
FUNCTIONAL DESCRIPTION (continued)
2 - FILTERS
- Integrated trap filter :
Q
=
f_o
f_−3dB
1
−
f_−3dB
f_o
Q = 1.7 at sharp. min
Q = 3.0 at sharp. max
Center frequency : - 4.43MHz,
3.58MHz for PAL, NTSC
- 4.25MHz, for SECAM
(f_-3dB = 3 M Hz ; -2 0 dB
rejection between 4.1MHz
and 4.4MHz)
- Integrated chroma bandpass :
Q = 3.5
Center frequency : 4.43MHz, 3.58MHz
- Integrated cloche filter for SECAM :
Q = 16
Center frequency : 4.286MHz
- Integrated delay line :
Bandwidth = 8MHz
- Integrated low pass filter for deflection part.
- All filters are tuned with a reference phase locked
loop.
The PLL consists of a lowpass filter, a phase
comparator, a loop filter (an external capacitor).
The reference signal is the continuous carrier
wave from the VCO (4.43MHz or 3.58MHz). The
PLL adjusts the center frequency of the lowpass
so that it is equal to the reference signal. The
tuning voltage of the PLL is used to adjust all other
filters. The cloche filter is fine tuned with a second
PLL operating during frame retrace.
3 - VIDEO CIRCUIT
- 2 RGB inputs : RGB (OSD) input has priority
against the RGBext. Maximum contrast on RGB
(OSD). -12dB range contrast control on RGBext.
Possibility to disable the RGBext insertion
through the bus.
- Oversize blanking capability on FB(OSD)(Pin15)
input. The RGB ouputs will be blanked when the
voltage on Pin 15 will exceed the second thresh-
old at 1.9V (blanking threshold) : the whole field
is blanked but not the inserted cut-off pulses. The
OSD insertion threshold is 0.7V.
- Automatic cut-off current loop : 2V cut-off range.
Sequential cut-off current measurement during
the three lines after the frame blanking signal.
Leakage current measurement during the frame
blanking, memorization on an internal capacitor.
- Possibility to force through the bus the inserted
cut-off pulses on lines 23/24/25(CCIR) in 50Hz
and 60Hz mode.
- Warm up detector.
- Beam current limiter DC voltage input.
The beam current limiter control voltage will act
on contrast first, then the brightness will be de-
creased when contrast attenuationreaches -5dB.
- Bus control of the red, green and blue channel
gain (White point adjustment)
- Bus control of the red and green DC levels (black
point adjustment)
- PAL and SECAM matrix, specific NTSC matrix
when demodulation angles are (0^o, 104^o).
- Switch-off of the trap filter in SVHS mode.
- Bus controlled contrast on luminance
(20dB range)
- Bus controlled saturation (50dB range)
- Bus controlled brightness : 40% range at maxi-
mum contrast.
- Bus controlled sharpness (peaking) ; sharpness
active in PAL/NTSC standard only.
- Noise coring function on sharpness.
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