Dual-Path RF Receiver Mixing for Lower Noise and LO Leakage
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Solution Overview
Problem
Existing wireless communication systems face challenges in noise performance due to the fixed operating bandwidth of surface acoustic wave filters, which reduces design flexibility and introduces insertion loss, especially when supporting multi-mode multi-band operations.
Innovation Solution
A signal receiving circuit with two parallel signal paths, each comprising a radio frequency amplifier and a mixer, where the phases of the amplified signals are opposite, allowing for in-phase amplification of wanted signals and cancellation of thermal noise, along with a feedback capacitor to reduce current consumption and LO signal leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If surface acoustic wave filters are used to remove out-of-band blocking signals, then blocking signal filtering is improved, but insertion loss increases and noise performance deteriorates
Solution Approach 1:
The patent extracts the filtering function from traditional surface acoustic wave filters and relocates it to the digital signal processing domain. By using digital filtering algorithms after ADC conversion, the system achieves blocking signal rejection without the insertion loss and noise degradation inherent in analog surface acoustic wave filters.
Solution Approach 2:
The patent replaces the mechanical surface acoustic wave filter system with an electronic/digital processing system. The physical filtering mechanism is substituted with digital signal processing techniques, eliminating the drawbacks of analog filters while maintaining the filtering functionality.
2Adaptability or versatility
If multiple surface acoustic wave filters are disposed to support multi-mode multi-band operations, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent implements a universal digital signal processing architecture that can handle multiple modes and bands through software configuration. A single receiver circuit with programmable digital filters replaces the need for multiple dedicated analog filters, enabling multi-mode multi-band support while reducing hardware complexity.
Solution Approach 2:
The patent introduces dynamic reconfigurability through digital signal processing. The filtering characteristics can be dynamically adjusted via software to adapt to different communication modes and frequency bands, replacing static analog filter configurations with flexible digital control.
3Object-affected harmful factors
If surface acoustic wave filters are used in the signal receiving circuit, then out-of-band signal filtering is improved, but noise performance is worsened
Solution Approach 1:
The patent extracts the filtering operation from the analog front-end and moves it to the digital baseband processing stage. This eliminates the noise degradation caused by analog surface acoustic wave filters while maintaining effective out-of-band rejection through digital filtering algorithms.
Data Source
AI summary
A signal receiving circuit amplifies a radio frequency signal by using a first radio frequency amplifier, outputs a first amplified signal in a same phase, amplifies the radio frequency signal by using a second radio frequency amplifier, and outputs a second amplified signal at an inverse phase. A first mixer mixes a first local oscillator signal with the first amplified signal to obtain a first frequency mixing signal, and a second mixer mixes a second local oscillator signal with the second amplified signal to obtain a second frequency mixing signal, where a phase of the first local oscillator signal is opposite to a phase of the second local oscillator signal. After adding the first frequency mixing signal and the second frequency mixing signal, an output interface outputs the first frequency mixing signal and the second frequency mixing signal.