I/Q Demodulation with Frame-Synced Channel Inversion Switching
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Solution Overview
Problem
Existing demodulation techniques face increased processing time when I and Q channels are inverted, as they require re-establishing frequency and clock synchronization, leading to longer demodulation times compared to non-inverted channels.
Innovation Solution
A demodulation device and method that includes a frequency correction unit, an inversion detection unit, and a channel control unit, which corrects the frequency and synchronizes it, detects channel inversion, and switches the I and Q channels downstream of the frequency correction unit, allowing channel inversion control at the timing of frame changes or when frame synchronization is established.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If channel switching is performed after detecting I and Q channel inversion, then channel inversion is corrected, but frequency and clock synchronization must be re-established, increasing demodulation processing time
Solution Approach 1:
The patent applies preliminary action by performing channel switching at the optimal timing point (frame synchronization point) before demodulation processing begins. By detecting channel inversion and switching channels in advance at the frame boundary, the system avoids the need to re-establish frequency and clock synchronization after switching, thus preventing time loss while ensuring reliable channel inversion correction.
2Reliability
If channel switching is performed immediately upon detecting inversion, then channel correction is achieved, but synchronization instability occurs during the transition
Solution Approach 1:
The patent uses preliminary action by preparing and executing channel switching at the frame synchronization point, which is the optimal timing before demodulation starts. This advance preparation at a stable synchronization point ensures that channel correction is achieved while minimizing disruption to frequency and clock synchronization, thus maintaining synchronization stability during the transition.
Solution Approach 2:
The frame synchronization point acts as an intermediary timing mechanism that mediates between channel switching and synchronization stability. By performing the channel switch at this intermediate point (frame boundary), the system transitions channels while maintaining synchronization stability, as the frame synchronization point serves as a stable reference that bridges the channel switching action and the ongoing demodulation process.
3Stability of the object's composition
If channel switching is delayed until frame synchronization is established, then synchronization stability is maintained, but demodulation processing time increases
Solution Approach 1:
The patent applies preliminary action by performing channel switching at the frame synchronization point, which is the optimal timing that balances both requirements. By detecting channel inversion and executing the switch in advance at this synchronization point (before demodulation begins), the system maintains synchronization stability while avoiding delays in demodulation processing, thus resolving the contradiction between stability and time efficiency.
Data Source
AI summary
The present technique relates to a demodulation device, a demodulation method and a program capable of realizing a demodulation process at a rate equivalent to a case where I and Q channel signals are not inverted, even when the I and Q channel signals are inverted. A frequency correction unit establishes synchronization of a frequency and clock based on a signal from a frequency synchronization unit. A channel inversion detection unit of a frame synchronization unit detects presence or absence of inversion of I and Q channel signals, and supplies, as a detection result, a channel inversion detection result to the channel inversion control unit. The channel inversion control unit switches the I and Q channel signals if the inversion has occurred, based on the channel inversion detection result. This technique can be applied to a demodulation device.