Parallel Mixer Harmonic Rejection With Phase Imbalance Compensation
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Solution Overview
Problem
In wireless communication systems, non-ideal oscillating signals with harmonic frequencies can contaminate baseband signals, degrading the noise figure due to interference from harmonic components, posing a challenge in maintaining signal quality.
Innovation Solution
A signal converting device comprising a reference signal-mixing circuit, multiple auxiliary signal-mixing circuits, and a combining circuit, where the auxiliary circuits are configured to compensate phase imbalances and apply gains to reduce harmonic components in the output signal, and an adjusting circuit to minimize self-mixing effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single signal-mixing circuit is used for down-conversion, then the device complexity is low, but harmonic components contaminate the baseband signal degrading noise figure
Solution Approach 1:
The single signal-mixing circuit is divided into multiple parallel signal-mixing circuits (first, second, third, and fourth circuits) that process the RF signal simultaneously with different local oscillating signals. This segmentation allows harmonic components to be distributed and cancelled through combining, improving signal quality while maintaining manageable device complexity through modular architecture
Solution Approach 2:
The patent converts the harmful harmonic components into beneficial cancellation opportunities. By introducing auxiliary signal-mixing circuits that generate harmonics with opposite phases, the harmful harmonic interference is transformed into a cancellation mechanism where harmonics from different circuits neutralize each other, improving noise figure and signal quality
2Object-affected harmful factors
If multiple signal-mixing circuits are used to reduce harmonic components, then the harmonic rejection ratio is improved, but the device complexity increases
Solution Approach 1:
Multiple signal-mixing circuits are merged into a unified down-conversion system with a common combining circuit. The first and second signal-mixing circuits combine their outputs, as do the third and fourth circuits, creating an integrated structure that achieves harmonic rejection through coordinated operation while sharing common components like the combining circuit and local oscillators
Solution Approach 2:
The auxiliary signal-mixing circuits serve multiple functions: they generate down-converted signals for normal operation, produce harmonic components for cancellation, and provide phase-balanced outputs. This multi-functionality reduces the need for separate harmonic rejection circuits, managing device complexity while improving harmonic rejection ratio
3Object-affected harmful factors
If auxiliary gains are adjusted to compensate phase imbalances, then the power of harmonic components is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent incorporates feedback mechanisms where the outputs of multiple signal-mixing circuits are combined and fed back to adjust auxiliary gains. This feedback loop enables automatic compensation for phase imbalances and amplitude mismatches, reducing the need for high manufacturing precision while effectively minimizing harmonic component power through adaptive calibration
4Productivity
If the oscillating signal contains harmonic frequency, then the mixing operation can be performed, but the baseband signal is contaminated by down-converted interference
Solution Approach 1:
The patent introduces asymmetric phase relationships among multiple local oscillating signals used in parallel signal-mixing circuits. By using oscillating signals with different phases (including odd and even harmonics with opposite phases), the system creates asymmetric cancellation patterns that selectively eliminate harmonic components while preserving the fundamental down-conversion operation, maintaining signal purity without sacrificing conversion efficiency
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces the power of harmonic components, improving the harmonic rejection ratio and noise figure of the baseband signal, enhancing signal quality in wireless communication systems.
Implementation Method 1
generate an amplitude modulated mixed signal indicative of a product of the amplified input signal and the local oscillator signal
Implementation Method 2
The combining circuit is arranged to combine the amplitude modulated mixed signals generated by the signal-mixing circuits to provide an output signal
Data Source
AI summary
A signal converting device includes: a reference signal-mixing circuit arranged to generate a reference mixing output signal according to an input signal, a reference gain, and a reference local oscillating signal; a plurality of auxiliary signal-mixing circuits, each arranged to generate an auxiliary mixing output signal according to the input signal, an auxiliary gain, and an auxiliary local oscillating signal; and a combining circuit arranged to combine the reference mixing output signal and a plurality of the auxiliary mixing output signals to generate an output signal, and at least one of the auxiliary signal-mixing circuits is configured by the corresponding auxiliary gain to compensate phase imbalances between the reference mixing output signal and each of the auxiliary mixing output signals to reduce a power of a harmonic component in the output signal.