Filterless Double-Conversion Receiver Circuits
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Solution Overview
Problem
Modern handset receivers face challenges in aggregating signals from multiple non-contiguous RF carriers due to limitations in existing technologies, which affect wireless throughput and signal processing efficiency.
Innovation Solution
The development of intermediate-frequency-filterless, double-conversion receivers with multiple mixers and trans-impedance amplifiers, utilizing direct digital synthesis and harmonic recombination to enable concurrent dual-carrier reception without the need for intermediate frequency filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional intermediate frequency filtering is used in receivers, then signal separation is achieved, but device complexity and loss of signal increase
Solution Approach 1:
The patent removes the intermediate frequency filter from the receiver architecture, extracting the filtering function and replacing it with a direct digital synthesis approach. The receiver converts RF signals directly to baseband without an intermediate frequency stage, eliminating the need for complex IF filters while maintaining signal separation capability through digital processing.
Solution Approach 2:
The patent replaces the mechanical/electronic intermediate frequency filter system with a digital signal processing system. Direct digital synthesis and digital baseband processing substitute for traditional analog filtering, reducing device complexity while improving signal processing flexibility and reliability.
2Productivity
If multiple non-contiguous RF carriers are aggregated, then wireless throughput increases, but signal processing complexity increases
Solution Approach 1:
The patent uses multiple independent mixer paths (first mixers and second mixers) that process different RF carriers simultaneously. Each mixer path is clocked by a different phase of a common clock, allowing parallel processing of multiple non-contiguous carriers without increasing overall system complexity.
Solution Approach 2:
The patent employs a universal baseband processing architecture that handles multiple RF carriers through a common set of trans-impedance amplifiers and digital processing circuits. The same hardware infrastructure processes signals from multiple carriers, achieving multi-functionality without proportional increases in device complexity.
3Productivity
If concurrent dual-carrier reception is implemented, then signal processing efficiency improves, but spurious responses increase
Solution Approach 1:
The patent uses periodic clocking signals with different phases to drive the mixer circuits. The first mixers are clocked by different phases of a first common clock frequency, and second mixers are clocked by different phases of a second common clock frequency. This periodic action with phased timing creates constructive interference for desired signals while causing destructive interference for spurious responses, enabling efficient dual-carrier reception with reduced harmonics and intermodulation products.
Data Source
AI summary
Circuits for receivers including: N first mixers that each receive an input signal, are each clocked by a different phase of a first common clock frequency, and each provide an output; and for each N first mixer: a set of M second mixers, wherein each second mixer receives as an input the output of a same one of the N first mixers unique to the set, wherein each of M second mixer is clocked by a different phase of a second common clock frequency, and wherein each second mixer has an output; a set of M resistors having a first side and a second side, wherein the first side is connected to the output of a corresponding one of the set of M second mixers; and a set of M trans-impedance amplifiers that each having an input connected to the second side of a corresponding one of the resistors.