Digital IQ Transmitter Chain for High-Bandwidth Signal Synchronism
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Solution Overview
Problem
Current SoC designs for wireless systems face challenges in maintaining synchronism between phase and magnitude signals, especially at high modulation bandwidths, leading to inefficiencies in polar modulation architectures and increased complexity in IQ modulation structures.
Innovation Solution
The proposed solution involves separating digital modulation signals into sign and magnitude signals, using digital-to-analog converters to convert magnitude signals, and mixing these with sign signals to produce a mixed signal, ensuring only positive signals are processed, thereby maintaining class-B operation efficiency and handling both positive and negative polarities effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If polar modulation architecture is used to achieve class-B operation efficiency, then energy efficiency is improved, but maintaining synchronism between phase and magnitude signals becomes difficult at high modulation bandwidths
Solution Approach 1:
The patent segments the complex polar modulation signal into separate in-phase and quadrature components, each processed through independent digital-to-analog conversion paths. This segmentation allows each component to be handled separately, maintaining synchronism while preserving the energy efficiency benefits of class-B operation.
Solution Approach 2:
The patent introduces an intermediary digital processing stage that converts digital in-phase and quadrature signals to analog form before mixing. This intermediary conversion process acts as a mediator that maintains precise timing and phase relationships between magnitude and phase signals, solving the synchronism problem while keeping the system in class-B operation mode.
2Speed
If IQ modulation structure is used to handle high modulation bandwidths, then bandwidth capability is improved, but system complexity increases
Solution Approach 1:
The patent divides the IQ modulation signal into separate in-phase and quadrature components, processing each through dedicated digital-to-analog converters. This segmentation enables high bandwidth operation by allowing parallel processing of multiple signal components while keeping each individual processing path relatively simple.
Solution Approach 2:
The patent replaces complex analog signal processing mechanisms with digital signal processing and digital-to-analog conversion. By performing signal manipulation in the digital domain and only converting to analog at the final stage, the system achieves high bandwidth capability without proportionally increasing analog circuit complexity.
3Measurement precision
If digital-to-analog conversion is performed on bi-polar signals, then signal fidelity is improved, but conversion complexity and difficulty increase
Solution Approach 1:
The patent inverts the conventional approach by processing the magnitude component (which is always positive) through digital-to-analog conversion, rather than attempting to directly convert bi-polar signals. The sign information is handled separately through mixing operations, simplifying the digital-to-analog conversion requirement while maintaining complete signal fidelity.
Solution Approach 2:
The patent extracts the magnitude and sign components as separate entities, processing only the positive magnitude through digital-to-analog conversion. By taking out the sign information and handling it through separate mixing operations, the system achieves accurate bi-polar signal reconstruction without the complexity of direct bi-polar digital-to-analog conversion.
Data Source
AI summary
Circuitry separates a modulation signal into digital sign and magnitude signal components. The digital magnitude signal is converted to an analog magnitude signal. The analog magnitude signal is the mixed with an in-phase or quadrature carrier signal under the influence of the digital sign signal and routed to a driver output stage.