Multilevel PSK Demodulation Using Adjustable Phase Difference
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Solution Overview
Problem
Current demodulation circuits face difficulties in demodulating multilevel Phase Shift Keying (PSK) signals, such as 8PSK, due to challenges in maintaining a consistent phase difference between adjacent symbols, which hinders accurate frequency adjustment and demodulation.
Innovation Solution
A demodulation device and method incorporating a phase rotation module, phase adjustment module, phase comparison module, and reference signal generation module to rotate and adjust the phases of I-Phase and Q-Phase signals, ensuring a constant 45-degree phase difference between adjacent symbols, allowing for reliable demodulation of multilevel PSK signals by mimicking the processing of QPSK signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional demodulation circuit is used, then QPSK signals can be demodulated, but multilevel PSK signals such as 8PSK cannot be demodulated
Solution Approach 1:
The patent applies parameter changes by modifying the phase difference between I-channel and Q-channel signals from the conventional 90 degrees to 45 degrees for multilevel PSK demodulation. This parameter change enables the demodulation circuit to handle 8PSK and other multilevel PSK signals while maintaining reliable demodulation accuracy through the phase adjustment module that dynamically adjusts the phase difference based on the modulation type.
2Measurement precision
If the phase difference between I-channel and Q-channel signals is maintained at 90 degrees, then QPSK demodulation is accurate, but multilevel PSK demodulation fails
Solution Approach 1:
The patent implements dynamics by making the phase difference between I-channel and Q-channel signals adjustable rather than fixed. The phase adjustment module dynamically changes the phase difference from 90 degrees to 45 degrees depending on whether QPSK or multilevel PSK is being demodulated, enabling both high measurement precision and broad signal type compatibility.
Solution Approach 2:
The patent changes the phase difference parameter from a fixed 90 degrees to an adjustable value that can be set to 45 degrees for multilevel PSK. This parameter change allows the system to maintain accurate phase detection for QPSK while gaining the ability to demodulate multilevel PSK signals like 8PSK.
3Adaptability or versatility
If the phase difference is adjusted to 45 degrees for multilevel PSK, then demodulation of 8PSK becomes possible, but the phase difference consistency between adjacent symbols becomes difficult to maintain
Solution Approach 1:
The patent implements feedback through the phase adjustment module that continuously monitors and adjusts the phase difference between I-channel and Q-channel signals. This feedback mechanism ensures that the 45-degree phase difference required for multilevel PSK demodulation is maintained consistently, enabling reliable 8PSK demodulation while preserving phase stability.
Data Source
AI summary
A demodulation device includes a phase rotation module, a phase adjustment module, a phase comparison module, and a reference signal generation module. The phase rotation module rotates phases of an I-Phase signal and a Q-Phase signal in a received signal of a multilevel PSK signal using a reference signal. The phase adjustment module adjusts the phases of the phase rotated I-Phase signal and the phase rotated Q-Phase signal output from the phase rotation module by multiplying the phases of the I-Phase signal and the Q-Phase signal with an integer value to generate a phase adjusted I-Phase signal and a phase adjusted Q-Phase signal. The phase comparison module compares the phase of the phase adjusted I-Phase signal with the phase of the phase adjusted Q-Phase signal to generate a phase comparison result. Also, the reference signal generation module generates a reference signal using the phase comparison result.