IQ Phase Adjustment Circuit Using Gain-Adjusted Signal Mixing
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Solution Overview
Problem
Existing phase adjustment circuits for IQ quadrature local signals in radio communication systems face challenges in achieving precise phase adjustment over a wide frequency range while maintaining a small circuit size, especially in semiconductor integrated circuits, due to phase errors caused by mismatches in resistance and capacitance components and waveform differences between I and Q signals.
Innovation Solution
A phase adjustment circuit comprising amplifiers and adding/subtracting units that allow for precise phase adjustment of IQ local signals by varying gain and using bias currents, enabling accurate phase correction even in semiconductor integrated circuits, thus addressing phase errors and maintaining high accuracy across a wide frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a phase adjustment circuit using variable resistors and capacitors is used to adjust phase over a wide frequency range, then the frequency range is covered, but the circuit size becomes large and manufacturing precision becomes difficult
Solution Approach 1:
The patent changes the operating parameters of existing amplifiers (bias currents and gain settings) to achieve phase adjustment, rather than adding variable passive components. By controlling the gain of amplifiers through bias currents, the phase of IQ local signals is adjusted dynamically, achieving wide frequency range adaptability without increasing circuit size
Solution Approach 2:
The patent makes existing amplifiers perform multiple functions: signal amplification and phase adjustment. The same amplifiers that boost signal levels are also used for phase correction by adjusting their gain through bias currents, eliminating the need for separate phase adjustment components and reducing overall circuit size
2Ease of operation
If variable resistors and capacitors are used for phase adjustment, then phase can be tuned, but manufacturing precision and accuracy are compromised
Solution Approach 1:
The patent employs feedback mechanisms where the phase adjustment is controlled by monitoring and adjusting bias currents to achieve the desired phase relationship. This controlled approach provides both ease of operation for phase tuning and high manufacturing precision, as the phase can be accurately set and maintained through electrical control rather than mechanical component adjustment
3Reliability
If complex phase adjustment circuits are implemented to correct IQ phase errors, then communication quality improves, but device complexity increases
Solution Approach 1:
The patent merges the phase adjustment function with the existing signal amplification stage. The same amplifiers that are already part of the signal path are used to perform both amplification and phase correction, eliminating the need for separate phase adjustment circuits and reducing overall device complexity while maintaining high communication quality
Data Source
AI summary
There is provided a circuit for adjusting phases of IQ local signals. As to a local signal A and a local signal B generated by a local signal generating unit for the purpose of generating IQ quadrature local signals, the local signal B in which the gain is adjusted is added to the output of the local signal A to obtain the local signal A2, and the local signal A in which the gain is adjusted is subtracted from the output of the local signal B to obtain the local signal B2. Even if the phase relationship between the local signal A and the local signal B deviates from 90 degrees, the phase difference between the local signal A2 and the local signal B2 can be adjusted with ease by changing the adjustment amounts of variable amplifiers AMP1 and AMP2.