Transmitter Circuit With LO Phase and Gain Control for PA Linearity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Power amplifiers in wireless communication systems face a trade-off between efficiency and linearity, particularly in handling multiple frequency bands, and existing linearization methods like digital predistortion are power hungry and complex, especially for high bandwidth signals.
Innovation Solution
A transmitter circuit with a mixer, phase-control, and gain-control circuitry that generates phase-adjusted and gain-adjusted signals to counteract AM-AM and AM-PM distortion, using variable capacitors or current-limiting circuits to control phase and gain, facilitating efficient and linear signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If digital predistortion is used to linearize the power amplifier, then linearity is improved, but power consumption and circuit complexity increase significantly
Solution Approach 1:
The patent extracts only the essential linearization function from complex digital predistortion systems. By using a simple feedback mechanism that detects output signal characteristics and adjusts input signal amplitude and phase accordingly, it achieves linearization without the complexity of full digital predistortion circuits, particularly for multi-band signals.
Solution Approach 2:
The patent changes the approach from complex polynomial-based digital predistortion to a simpler parameter adjustment method. It modifies the input signal's amplitude and phase parameters based on feedback from the output signal, achieving linearization through direct parameter control rather than complex computational algorithms.
2Manufacturing precision
If digital predistortion is used to linearize the power amplifier, then linearity is improved, but power consumption increases
Solution Approach 1:
The patent replaces expensive, power-hungry digital predistortion computation with a simpler, lower-power feedback mechanism. The solution uses basic analog circuitry for detection and adjustment rather than continuous high-power digital signal processing, significantly reducing power consumption while maintaining linearization effectiveness.
3Adaptability or versatility
If multiple frequency bands are combined at the input of one power amplifier, then integration is improved, but meeting EVM and ACLR requirements becomes more difficult
Solution Approach 1:
The patent introduces a feedback mechanism that detects the actual output signal characteristics across multiple frequency bands and uses this information to adjust the input signal parameters. This closed-loop approach ensures that EVM and ACLR requirements are met for each band simultaneously, solving the integration challenge of multi-band operation.
Solution Approach 2:
The patent creates a universal linearization mechanism that handles multiple frequency bands simultaneously through a single feedback loop. The system adjusts amplitude and phase parameters to achieve linearization across the entire multi-band spectrum, providing a unified solution rather than separate processing for each band.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed circuitry simplifies the linearization process, reducing power consumption and complexity while effectively addressing distortion issues in power amplifiers, enhancing performance in multi-band wireless communication systems.
Implementation Method 1
a mixer circuit (100) comprising a mixer (300) configured to generate a frequency-upconverted signal
Implementation Method 2
the phase-control circuit (130) comprises a variable capacitor, the capacitance of which is controlled by the phase-control signal
Implementation Method 3
the phase-control circuit (130) comprises a current-limiting circuit controlled by the phase-control signal
Implementation Method 4
a gain-control circuit (140a, 140b) configured to control a gain of the transmitter circuit (30) in response to a gain-control signal
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
A transmitter circuit (30) is disclosed. It comprises a signal input (40) for receiving an analog input signal and a local oscillator (LO) input (45) for receiving an LO signal. It comprises a mixer circuit (100) having a first input (104), a second input (102), and an output (106) for outputting an output signal of the mixer circuit (100). The second input (102) of the mixer circuit is connected to a signal input (40) of the transmitter circuit (30). It further comprises a PA circuit (110) having an input (112) connected to the output (106) of the mixer circuit (100), and an output (114). A control circuit (120) is configured to generate a phase- control signal and a gain-control signal in response to an envelope of the analog input signal. A phase-control circuit (130) is configured to generate a phase-adjusted LO signal in response to the LO signal and the phase-control signal and supply the phase-adjusted LO signal to the first input (104) of the mixer circuit (100). A gain-control circuit (140a, 140b) configured to control a gain of the transmitter circuit (30) in response to the gain-control signal. A related integrated circuit and a related electronic apparatus are also disclosed.