Touch Position Sensor Controller Using Cyclic-Shift Code Encoding
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Solution Overview
Problem
Existing communication methods between a position indicator and a position detector, such as those using direct spread techniques, face challenges in achieving high bit rates due to the requirement of multiple chips to express one bit, making it difficult to increase the chip rate.
Innovation Solution
A sensor controller and position indicator system that utilizes cyclic shifting of a code string to generate a chip string, allowing for the expression of 2 bits or more with one code string, thereby achieving a high bit rate at the same chip rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct spread technique is used for communication between position indicator and position detector, then noise resistance is improved, but bit rate deteriorates due to requiring multiple chips to express one bit
Solution Approach 1:
The patent applies dynamics by making the code string shiftable through cyclic shifting operations. The reception device can dynamically adjust the code string by shifting it in synchronization with the transmission device, allowing multiple bit values to be expressed with a single code string while maintaining noise resistance through the autocorrelation properties of the shifted codes.
Solution Approach 2:
The patent changes the parameter of code string representation by using cyclic shifting to generate multiple distinct code strings from a single base code string. This allows one code string to represent multiple bit values (0, 1, 2, 3, etc.) through different shift quantities, thereby increasing bit rate while maintaining the noise-resistant direct spread technique.
2Reliability
If multiple chips are used to express one bit in direct spread technique, then noise resistance is improved, but chip rate increase becomes difficult
Solution Approach 1:
The patent makes the single code string universal by enabling it to serve multiple functions through cyclic shifting. One base code string can represent multiple different bit values depending on its shift quantity, allowing the system to transmit more information per chip without requiring multiple chips per bit, thus maintaining noise resistance while enabling higher chip rates.
Solution Approach 2:
The patent introduces dynamic shifting capability to the code string, allowing it to adapt its state through cyclic shifts. This dynamic property enables a single code string to convey multiple bit values, eliminating the need to increase chip rate for higher data transmission rates, thereby resolving the contradiction between noise resistance and chip rate limitations.
3Productivity
If cyclic shifting of code string is used to express multiple bits, then bit rate is improved, but device complexity increases
Solution Approach 1:
The patent uses copying by generating multiple shifted versions of a single base code string. Instead of using completely different code strings for different bit values, the system creates copies of the base code string with different shift quantities. This approach increases bit rate while keeping device complexity relatively low, as the same base code string is reused and transformed through simple shifting operations.
Solution Approach 2:
The patent applies segmentation by dividing the information content into multiple segments that can be represented by different shift quantities of the same code string. Rather than using multiple separate code strings, the system segments the bit representation into multiple states achievable through cyclic shifting, thereby reducing device complexity while maintaining high bit rate capability.
Data Source
AI summary
A sensor controller is provided for use in a position detector for detecting a position of a position indicator on a touch surface. The sensor controller includes a microprocessor for outputting a value of a symbol to be sent to the position indicator. The sensor controller includes a transmitter coupled to the microprocessor for generating a transmission signal including a chip string CN1 produced by cyclically shifting a code string PNa having autocorrelation characteristics by a shift quantity based on the value of the symbol to be sent, and sending the generated transmission signal to the position indicator via the touch surface. A higher bit rate can be obtained for a given chip rate compared with the prior art in which only 1 bit can be expressed by one code string.