RF Mixer Impedance Tuning for Wide Dynamic Range Control
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Solution Overview
Problem
Conventional RF circuits face challenges in expanding the gain control range without degrading performance, particularly in achieving the required dynamic range of 80 dB or more, due to the trade-off between gain control range and performance optimization across various blocks in an RF transmission chain.
Innovation Solution
An RF circuit with a mixer, an amplifier, and an impedance tuner circuit that adjusts the conversion gain by varying impedance, allowing for expanded gain control range without degrading performance by optimizing each block and sharing the burden of gain control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the gain control range is expanded through gain control in each block, then the dynamic range requirement is met, but the performance of each block is degraded
Solution Approach 1:
The gain control function is segmented and distributed across multiple blocks in the transmission chain (LNA, mixer, amplifier). Each block contributes a portion of the total 80 dB dynamic range through its own gain control mechanism, rather than relying on a single block to provide all gain control. This segmentation allows the system to achieve the required dynamic range while maintaining optimal performance in each individual block.
2Reliability
If the performance of each block is optimized, then the block performance is improved, but the overall gain control range is limited
Solution Approach 1:
The patent combines the gain control capabilities of multiple blocks (LNA, mixer, amplifier) to achieve the overall 80 dB dynamic range. By merging the gain control functions across these blocks and coordinating their operation, the system achieves both optimized individual block performance and sufficient overall gain control range without requiring any single block to operate suboptimally.
Data Source
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AI summary
Disclosed is an RF circuit (100), which includes a mixer (110) that converts a first signal (S1) into a second signal (S2) using a local oscillator, LO, signal (LO), an amplifier (140) that amplifies the second signal (S2), and an impedance tuner circuit (120) connected between the mixer (110) and an input terminal of the amplifier (140), and that adjusts a conversion gain of the mixer (110) by presenting a variable impedance.