Signal Modulator Phase Mismatch Cancellation via Bilateral Symmetry
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Solution Overview
Problem
In wireless communication systems, phase mismatches between in-phase and quadrature-phase oscillating signals lead to the generation of unwanted image signals, which degrade system quality, despite efforts to route traces equally in length to prevent this.
Innovation Solution
A signal modulator comprising a modulating circuit and two signal trace blocks, where the phase differences between the oscillating signals are carefully managed to ensure that the phase mismatches between the trace blocks cancel out the image signal component, using a configuration of four mixers and bilaterally symmetric conducting circuits to achieve this.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the trace lengths are made equal to reduce phase mismatch, then the manufacturing precision is improved, but the image signal cannot be completely eliminated due to intrinsic layout mismatch
Solution Approach 1:
The patent divides the signal transmission path into two separate trace blocks (first signal trace block and second signal trace block) that are bilaterally symmetric. Each block handles specific signal paths (in-phase and quadrature-phase signals), allowing independent optimization of each segment while maintaining overall balance to cancel image signals.
Solution Approach 2:
The patent intentionally introduces controlled asymmetry in the form of different phase differences (first phase difference ≠ second phase difference) between the two trace blocks. This controlled asymmetry, when combined with bilaterally symmetric layout, creates phase relationships that cause image signals from different paths to cancel each other out at the output.
2Reliability
If the trace layout is carefully routed to make traces equal in length, then the phase mismatch is reduced, but intrinsic layout mismatch still generates image signals
Solution Approach 1:
The patent converts the harmful effect of phase mismatch into a beneficial cancellation mechanism. By designing two trace blocks with specific phase relationships (different phase differences) and bilaterally symmetric layouts, the phase errors that would normally generate image signals are made to produce equal and opposite image components that cancel each other out.
3Object-generated harmful factors
If bilaterally symmetric conducting circuits are used, then the image signal cancellation is improved, but the device complexity increases
Solution Approach 1:
The patent merges the functions of phase matching and image signal cancellation into a single bilaterally symmetric trace block structure. The same conducting circuits that provide symmetric layout also establish the phase relationships needed for image cancellation, eliminating the need for separate correction circuits or additional components.
Data Source
AI summary
A signal modulator includes: a modulating circuit; a first signal trace block arranged to conduct a first in-phase oscillating signal to the modulating circuit, and conduct a first quadrature-phase oscillating signal to the modulating circuit; and a second signal trace block arranged to conduct a second in-phase oscillating signal to the modulating circuit, and conduct a second quadrature-phase oscillating signal to the modulating circuit, and a phase difference of the first in-phase oscillating signal caused by the first signal trace block substantially equals a phase difference of the second quadrature-phase oscillating signal caused by the second signal trace block, a second quadrature-phase oscillating signal to the modulating circuit, and a phase difference of the second in-phase oscillating signal caused by the second signal trace block substantially equals a phase difference of the first quadrature-phase oscillating signal caused by the first signal trace block.