Service manual

CP-850/F Service Manual
-50-
5.3.1.8.2 Noise Reduction
The structure of the temporal motion adaptive noise reduction is the same for VSP 94x5C as for chrominance signal.
The output of the motion detector is weighted. The look-up table input value range is separated into 8 segments. It is
possible to freely program different behaviour of the noise reduction by using predefined curve characteristic for each
segment.
5.3.1.8.3 Noise Measurement
The noise measurement algorithm is used to sort program during ATSS. This is done by the TV- microcontroller which
reads the noise level in VSP. The value is determined by averaging over several fields.
5.3.1.8.4 Operation Modes
The interlaced input signal (e.g. 50 Hz PAL or 60 Hz NTSC) is composed of a field A (odd lines) and a field B (even
lines). The 100Hz operation mode used is simply AABB, where each stored field in the memory is displayed double
times on the TV screen. A still field can be displayed using FREEZE command, the operation mode becomes ABAB.
5.3.1.8.5 Digital 656 Output
The output data format corresponds to CCIR 656 with double-scan format (8-bit bus at a data rate of 54 MHz). There all
frequencies and data-rates are doubled compared to standard CCIR656 specification. Timing reference codes (SAV,
EAV) are inserted according to the specification. The output is set to 720 pixels per line and the display clock is set to
54 MHz.
5.3.2 BACK END
5.3.2.1 Digital Input Interface
The digital input interface is set to receive 8 bit 4:2:2 Y Cr Cb multiplexed with separate H/V-syncs and clock (ITU-R-
656 format). The data inputs Y0...Y7 and C0...C7 are clocked with the external clock LLC2. The clock frequency is 54
MHz for 8 bit data input. The horizontal sync pulse at the HS pin should be an active video signal, which is not vertically
blanked. A clock generator converts the different external line locked clock rates to a common internal sample rate of
approximately 40.5 MHz, in order to provide a fix bandwidth for all digital filters. Therefore the input data is sample rate
converted to the common processing frequency by the horizontal scaler.
5.3.2.2 Horizontal Scaler
The horizontal scaler supports linear or nonlinear horizontal scaling of the digital input video signal in the range of 0.25
to 4. Nonlinear scaling, also called “panorama vision”, provides a geometrical distortion of the input picture. It is used to
fit a picture with 4:3 format on a 16:9 screen by stretching the picture geometry at the borders. Also, the inverse effect
can be produced by the scaler. See also microcontroller section to find details on format switching logic.
5.3.2.3 Luma Contrast and Brightness
The luminance signal is multiplied by a factor of 0...2 (contrast adjustment). The signal can be shifted by
100% of its
maximal amplitude with the digital brightness value
5.3.2.4 Black Level Expander/Compressor (BLEC)
The black level expander/compressor modifies the luminance signal with an adjustable non-linear function to enhance
the contrast of the picture.Dark areas are stretched to black, while bright areas remain unchanged. Advantageously, this
black level processing is performed dynamically and only if it will be most noticeable to the viewer.