Differential Mixer Topology for Higher Harmonic Rejection
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Solution Overview
Problem
Current signal processing technologies face challenges in increasing the harmonic rejection ratio (HRR) while maintaining low power consumption, particularly in Low-IF or Zero-IF receivers, where unwanted RF signals are down-converted due to insufficient HRR, leading to crosstalk issues like WLAN interference with TV signals.
Innovation Solution
A signal processing apparatus with a differential mixing section that mixes local signals with a 1/3 duty ratio and 1/2 period phase shift, combined with a resonance section resonating at a sixfold frequency, and a voltage/current conversion section, to suppress unwanted frequency components without increasing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If three signal paths with shifted gain and phase are added to suppress down-conversion of unwanted RF signals, then the harmonic rejection ratio is improved, but the power consumption increases due to the large current required
Solution Approach 1:
The invention divides the signal processing into multiple stages: a preliminary mixing stage with two signal paths that performs initial rejection of unwanted frequency components, followed by a resonance stage that further suppresses remaining harmonics. This segmentation allows achieving high harmonic rejection ratio without requiring all three paths to operate at full power simultaneously, thus reducing overall power consumption while maintaining effective suppression of down-conversion of unwanted RF signals
Solution Approach 2:
The invention employs a resonance circuit with variable resonant frequency that can be dynamically adjusted to match the specific harmonic frequencies present in the signal. This dynamic adaptation allows the system to optimize its rejection performance for different operating conditions without requiring fixed high-power three-path configuration, enabling effective harmonic suppression with reduced power consumption across varying signal conditions
2Manufacturing precision
If a resonator mixer with parallel LC resonator resonating at fourfold frequency is used to suppress down-conversion of unwanted frequency components, then the harmonic rejection ratio is improved, but it is difficult to ensure a harmonic rejection ratio of 20 dB or more in silicon tuners
Solution Approach 1:
The invention segments the harmonic suppression function into two distinct stages: the first stage uses a mixing circuit with two signal paths to provide initial rejection of unwanted frequency components, and the second stage uses a resonance circuit to provide additional suppression. This segmented approach achieves cumulative rejection效果 that exceeds 20 dB, overcoming the limitation of single-stage resonator mixers in silicon tuner applications
Solution Approach 2:
The invention introduces an intermediate mixing stage with two signal paths that acts as a mediator between the RF input and the resonance stage. This intermediate stage pre-processes the signal to reduce the burden on the resonance circuit, enabling the overall system to achieve consistent harmonic rejection ratio exceeding 20 dB across different silicon tuner implementations, thereby improving performance consistency
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
This approach effectively increases the harmonic rejection ratio while minimizing power consumption, ensuring that only the desired frequency components are converted, thus reducing unwanted signal interference.
Implementation Method 1
a resonance section that resonates with the differential signal, with which the local signals are mixed by the mixing section, at a predetermined resonant frequency
Data Source
AI summary
The present technology relates to a signal processing apparatus and method capable of increasing a harmonic rejection ratio while suppressing an increase in power consumption.In one aspect of the present technology, two local signals having a 1/3 duty ratio and phases mutually shifted by a 1/2 period are mixed with each signal of a differential signal, and a difference between results of the mixing of the two local signals is calculated. The present technology can be applied to, for example, a signal processing apparatus, a transmission apparatus, a reception apparatus, a communication apparatus, an electronic apparatus having a transmission function, a reception function, or a communication function, or a computer that controls those apparatuses.