DTV Supplemental Data Encoding for Noise-Resistant Reception
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Solution Overview
Problem
Digital television (DTV) systems face challenges in transmitting supplemental data due to signal degradation from noise and ghost effects, particularly in indoor environments with obstacles, which can lead to errors in critical data like program execution files or stock information, requiring a system resistant to noise and compatible with existing DTV systems.
Innovation Solution
A DTV transmitting system that includes a frame encoder, block processor, and multiplexer for encoding and processing enhanced data with error correction and detection, and a receiving system with a tuner and frame decoder for error correction and reliability mapping, ensuring robust data transmission and compatibility with conventional systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If supplemental data is transmitted through the same channel as video/audio data using time-division method, then the broadcast system maintains compatibility with conventional receiving systems, but the receiving performance deteriorates in poor channel environments due to noise and ghost effects
Solution Approach 1:
The transmission channel is segmented into different time slots: one for conventional video/audio data and another for supplemental data. This allows conventional receivers to ignore the supplemental data slots while new receivers can utilize them, maintaining backward compatibility while enabling enhanced functionality.
Solution Approach 2:
An intermediary processing system is introduced that includes error detection and correction mechanisms. The system uses CRC checks and Reed-Solomon decoding as intermediate processing steps to filter out noise and ghost effects before delivering supplemental data to the receiver.
2Reliability
If error correction and detection encoding is applied to supplemental data, then the error rate decreases and receiving performance improves, but the system complexity increases
Solution Approach 1:
Error correction and detection codes are preliminarily applied to supplemental data during the transmission phase. CRC check bits and Reed-Solomon parity data are pre-calculated and attached to the data blocks before transmission, so that the receiving end can directly decode and correct errors without complex real-time processing.
Solution Approach 2:
Redundant copies of error correction information are created and transmitted alongside the original supplemental data. The system transmits both the original data blocks and their corresponding Reed-Solomon encoded versions, allowing the receiver to use the redundant copies for error correction.
3Ease of operation
If indoor antennas are used to receive supplemental data, then the system can be deployed in indoor environments, but signal intensity decreases due to blockage by walls and disturbance by mobile objects
Solution Approach 1:
The system anticipates signal degradation in indoor environments by pre-applying robust error correction coding. Reed-Solomon codes with high correction capability are used to cushion against the expected signal losses from wall blockage and mobile object interference, ensuring data integrity even when signal quality deteriorates.
Data Source
AI summary
A digital television transmitting system includes a frame encoder, a block processor, a group formatter, and a multiplexer. The frame encoder forms an enhanced data frame and encodes the data frame for error correction and for error detection. The block processor further encodes the encoded data frame at a rate of ½ or ¼, and the group formatter divides the encoded data frame into a plurality of enhanced data blocks and maps the divided data blocks into a plurality of enhanced data groups, respectively. The multiplexer multiplexes the enhanced data groups with main data.