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Digital Convergence
The effects of the Earths magnetic field change with the placement of the TV and cause picture distortions. These distortions are automatically corrected using a microprocessor and data from optical sensors positioned around the outer edge of the screen. This process is called digital convergence. The digital convergence system generates six drive signals that correct geometry of the image created by the three picture tubes. This is accomplished by a matrix of thirteen vertical points and sixteen horizontal that are assigned a digital value that is stored in nonvolatile memory. Each of these data points can be individually changed. The digital information is converted to six analog signals that drive the convergence amplifiers. The amplified signals are used to drive the convergence yokes.
Sensor Locations
29 There are customer menu adjustments and service adjustments. A video test pattern is generated by the digital convergence to aid in converging the set. The use of Chipper Check will speed up the alignment process in the event of major component failure.
There has been little to no change in the digital convergence since the MMC102. The CTC211 uses the same digital convergence processing and sensor arrangement as the MMC102. The major difference in the CTC211 is the reduction of scan modes. There are only two scan modes in the CTC211, 2H and 2.14H. The sensor position and access is the same as in the DTV307 and MMC102. The speed of sensor detection has increased over the MMC102 but the process is the same. These sensors can only be seen from the back side of the screen. The digital convergence system generates six drive signals that correct geometry of the image created by the three picture tubes. This is accomplished by a matrix of thirteen vertical points and sixteen horizontal that are assigned a digital value that is stored in nonvolatile memory. Each of these data points can be individually changed. The digital information is converted to six analog signals that drive the convergence amplifiers. The amplified signals are used to drive the convergence yokes.
30 A video test pattern is generated by the digital convergence to aid in converging the set. There are customer menu adjustments and service adjustments. The use of Chipper Check will speed up the alignment process in the event of major component failure.
Digital Generator Module (DGM)
The CTC211 uses a Digital Generator Module (DGM) for convergence correction and auto convergence. Inside the DGM are five EEPROMS, Convergence Micro and a Digicon IC. U502 is the convergence micro. The purpose of U502 is calculating convergence correction based on information from the optical sensors. The convergence micro controls the Digicon and the EEPROMs. U501 (Digicon) generates the convergence correction signals that are fed out to the convergence amplifiers. Data stored in the EEPROMs is used for alignment information for the different scan modes. U510, 11, 12, and 13 are mode EEPROMs. U509 is the factory reference EEPROM. Two buffer ICs (U503 and 504) buffer the output from the Digicon IC to the output amplifiers.