msm7650 Oki Semiconductor, msm7650 Datasheet - Page 11

• Manufacturer Part Number: msm7650
• Description: Ntsc/pal Digital Encoder
• Manufacturer: Oki Semiconductor

¡ Semiconductor
BLOCK FUNCTIONAL DESCRIPTION
Y Limitter
This block limits the contents outside the specified range as follows for input luminance signal
YD specified by the ITU-601 standard.
• Signals are limited to YD = 235 when YD_IN > 235
• Signals are limited to YD = 16 when YD_IN < 16
• In other cases, signals are fed as is to next processing
C Limitter
This block limits the contents outside the specified range as follows for input chrominance
signals specified by the ITU-601 standard.
The input chrominance signal is output as a 2’s complement format.
The processing procedure follows.
1) Format processing for input chrominance signals
• If MR [6] = 0, CD is in offset binary format. CD is converted to 2’s complement format and is
• If MR [6] = 1, CD is in 2’s complement format. CD is fed as is to next processing.
2) Clipping processing
• Signals are limited to CD = 112 when CD>112
• Signals are limited to CD = -112 when CD < -112
• In other cases, signals are fed to next processing
In addition, this block separates U and V components from the input chrominance signal CD into
which data of U and V components has been inserted using time sharing, and then passes signals
to the next process.
• Y Level Converter
• U Level Converter
• V Level Converter
• YUV Color Generator
• Overlay Control
Converts ITU-601 standard luminance signal level to DAC digital input level.
Converts ITU-601 standard chrominance signal level to DAC digital input level.
Converts ITU-601 standard chrominance signal level to DAC digital input level.
This block generates luminance and chrominance signals from over lay color signals OLR,
OLG and OLB. Control signals (CR [2:0] ) control the output content (overlay or color bar) and
output level (100%, 75%, 50%, 25%).
This block selects input image data or YUV Color Generator output signals.
It is determined by the level of the control signal (OLC, CR [2]), as shown below:
CR [2] = 1, OLC = ?: Selects color bar signal (YUV Color Generator output signal).
CR [2] = 0, OLC = 1: Selects overlay signal (YUV Color Generator output signal).
CR [2] = 0, OLC = 0: Selects input image data.
fed to next processing.
MSM7650
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