Group Delay Compensation Circuit for RF Envelope Tracking Alignment
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Solution Overview
Problem
Envelope tracking systems in mobile communication devices face reduced linearity and efficiency due to inherent bandwidth limitations, particularly with the advent of 5G-NR technology, which modulates RF signals at higher bandwidths than the system can handle, leading to misalignment of voltage and current signals and compromised amplifier performance.
Innovation Solution
A group delay optimization circuit is introduced to receive voltage and current signals, determine a statistical indicator of group delay offset, and minimize it below a defined threshold through optimization cycles, thereby pre-compensating for delays and improving the efficiency and linearity of the amplifier circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If envelope tracking system operates at higher bandwidth to support 5G-NR technology, then data rate and communication capability are improved, but linearity and efficiency deteriorate due to group delay offset between voltage and current signals
Solution Approach 1:
The patent applies preliminary action by measuring the group delay offset between voltage and current signals in advance, then pre-compensating for this offset before the envelope tracking system operates at higher bandwidths. The controller measures the offset during initialization or calibration phases, stores compensation values, and applies them during high-bandwidth operation to maintain signal alignment and prevent linearity degradation.
Solution Approach 2:
The patent changes the parameter of group delay offset compensation dynamically. The controller measures different group delay offsets at various operating conditions (different bandwidths, power levels, or temperature conditions) and adjusts the compensation parameter accordingly. This allows the system to maintain optimal linearity across varying operating conditions while supporting higher bandwidths for 5G-NR technology.
2Speed
If envelope tracking system operates at higher bandwidth to support 5G-NR technology, then data rate and communication capability are improved, but efficiency deteriorates due to group delay offset between voltage and current signals
Solution Approach 1:
The patent applies preliminary action by measuring the group delay offset between voltage and current signals in advance, then pre-compensating for this offset before the envelope tracking system operates at higher bandwidths. The controller measures the offset during initialization or calibration phases, stores compensation values, and applies them during high-bandwidth operation to maintain signal alignment and prevent linearity degradation.
Solution Approach 2:
The patent changes the parameter of group delay offset compensation dynamically. The controller measures different group delay offsets at various operating conditions (different bandwidths, power levels, or temperature conditions) and adjusts the compensation parameter accordingly. This allows the system to maintain optimal linearity across varying operating conditions while supporting higher bandwidths for 5G-NR technology.
3Device complexity
If group delay offset is not compensated, then system complexity is reduced, but signal alignment and amplifier performance deteriorate
Solution Approach 1:
The patent applies self-service by implementing automatic group delay offset measurement and compensation within the envelope tracking system itself. The controller automatically measures the group delay offset between voltage and current signals, determines compensation values, and applies corrections without requiring external calibration equipment or manual adjustment. This self-calibrating approach maintains signal alignment while minimizing the need for complex external testing and adjustment infrastructure.
Solution Approach 2:
The patent implements feedback by continuously monitoring the group delay offset between voltage and current signals and using this information to adjust compensation parameters. The controller measures the offset, applies compensation, and can re-measure to verify alignment, creating a closed-loop system that maintains optimal signal alignment automatically throughout operation.
Data Source
AI summary
A group delay optimization circuit is provided. The group delay optimization circuit receives a first signal (e.g., a voltage signal) and a second signal (e.g., a current signal). Notably, the first signal and the second signal may experience different group delays that can cause the first signal and the second signal to misalign at an amplifier circuit configured to amplify a radio frequency (RF) signal. The group delay optimization circuit is configured to determine a statistical indicator indicative of a group delay offset between the first signal and the second signal. Accordingly, the group delay optimization circuit may minimize the group delay offset by reducing the statistical indicator to below a defined threshold in one or more group delay optimization cycles. As a result, it may be possible to pre-compensate for the group delay offset in the RF signal, thus helping to improve efficiency and linearity of the amplifier circuit.