Changhong Electric 21NF55, Service Manual, Page: 20 / 83

SERVICE MANUAL
18
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Internal base-band delay line
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RGB control circuit with ‘ Continuous Cathode Calibration’ , white point and black level offset
adjustment so that the colour temperature of the dark and the light parts of the screen can be
chosen independently.
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Linear RGB or YUV input with fast blanking for external RGB/YUV sources. The Text/OSD signals
are internally supplied from the
？
-Controller/Teletext decoder
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Contrast reduction possibility during mixed-mode of OSD and Text signals
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Horizontal synchronization with two control loops and alignment-free horizontal oscillator
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Vertical count-down circuit
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Vertical driver optimized for DC-coupled vertical output stages
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Horizontal and vertical geometry processing
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Horizontal and vertical zoom function for 16 : 9 applications
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Horizontal parallelogram and bow correction for large screen picture tubes
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Low-power start-up of the horizontal drive circuit
TV signal processor-Teletext decoder with embedded
？
-Controller TDA935X/6X/8X PS/N2
series
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-Controller
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80C51
？
-controller core standard instruction set and timing
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1 s machine cycle
？
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16 - 128Kx8-bit late programmed ROM
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3 - 12Kx8-bit DATA RAM (shared between Display, Acquisition and Auxiliary Ram)
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Interrupt controller for individual enable/disable with two level priority
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Two 16-bit Timer/Counter registers
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One 16 bit Timer with 8 -bit Pre-scaler
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WatchDog timer
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Auxiliary RAM page pointer
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16-bit Data pointer
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Stand -by, Idle and Power Down (PD) mode
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14 bits PWM for Voltage Synthesis Tuning
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8-bit A/D converter
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4 pins which can be programmed as general I/O pin, ADC input or PWM (6 -bit) output
Data Capture
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Text memory for 0, 1 or 10 pages
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In the 10 page versions inventory of transmitted Teletext pages stored in the Transmitted Page
Table (TPT) and Subtitle Page Table (SPT)
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Data Capture for US Closed Caption
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Data Capture for 525/625 line WST, VPS (PDC system A) and Wide Screen Signalling (WSS) bit
decoding
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Automatic selection between 525 WST/625 WST
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Automatic selection between 625 WST/VPS on line 16 of VBI
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Real-time capture and decoding for WST Teletext in Hardware, to enable optimized
？
-processor
throughput
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Automatic detection of FASTEXT transmission