Up-Conversion Mixer Input Stage for Third-Order Harmonic Suppression
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Solution Overview
Problem
Conventional up-conversion mixers experience worsening third order distortion suppression with increasing input power, requiring higher gain power amplifiers and inefficient power consumption.
Innovation Solution
The implementation of a cascaded transconductance amplifier and a linear transconductance amplifier in the up-conversion mixer circuit reduces the third order harmonic term, improving distortion suppression by introducing a notch in the output power plot, thereby reducing power requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional up-conversion mixer is used, then the device is simple, but the third order distortion suppression deteriorates with increasing input power
Solution Approach 1:
The input stage is divided into multiple parallel paths: a first path with a first transconductance amplifier and a second path with a second transconductance amplifier. Each path processes the input signal independently and then combines their outputs. This segmentation allows different transconductance characteristics to be utilized, reducing the third order harmonic term while maintaining overall system functionality.
Solution Approach 2:
The invention changes the transconductance parameters by using two different transconductance amplifiers with different transconductance values. By carefully selecting and combining the outputs of these amplifiers with different transconductance characteristics, the third order harmonic term is reduced. This parameter variation approach allows optimization of distortion suppression without requiring complex circuit topologies.
2Power
If higher gain power amplifier is used to maintain output power, then the output power is maintained, but the power consumption increases
Solution Approach 1:
The third order harmonic term is reduced at the input stage itself through the use of two transconductance amplifiers with different transconductance values. By performing this distortion reduction action preliminarily, before the signal reaches the power amplifier, the power amplifier operates more efficiently with less distortion to amplify, thereby reducing overall power consumption while maintaining the required output power level.
Data Source
AI summary
An up-conversion mixer includes a mixer cell having at least one output node configured to generate an output. The up-conversion mixer further includes a first cascaded transconductance input stage coupled to the mixer cell, the first cascaded transconductance input stage configured to receive an input signal and to reduce a third order harmonic of the output. The up-conversion mixer further includes a second cascaded transconductance input stage coupled to the mixer cell, the second cascaded transconductance input stage configured to receive the input signal and to reduce a third order harmonic of the output.