Envelope Tracking Delay Measurement for RF Signal Synchronization
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Solution Overview
Problem
Envelope tracking power supplies for RF power amplifiers often experience delays or advancements relative to the RF input signal, leading to failures in meeting linearity or error vector magnitude requirements, necessitating improved delay estimation circuitry for synchronization.
Innovation Solution
The implementation of delay estimation circuitry comprising programmable delay, comparator, sample and hold, and difference calculation circuitry to precisely determine and compensate for delays between envelope power supply signals and RF input signals, utilizing threshold crossings and difference calculations to generate a delay control signal for synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If envelope tracking power supply voltage is delayed or advanced to simplify circuit operation, then ease of operation is improved, but linearity and error vector magnitude requirements are not met
Solution Approach 1:
The patent employs feedback by measuring the delay between envelope tracking power supply voltage and RF input signal, then using this measured delay to adjust and synchronize the power supply voltage timing. The delay measurement circuitry continuously monitors the timing relationship and feeds this information back to the envelope tracking generator, enabling automatic correction of timing mismatches while maintaining ease of operation and ensuring linearity requirements are met.
Solution Approach 2:
The patent changes the timing parameter of the envelope tracking power supply voltage based on the measured delay. By dynamically adjusting the phase or time delay parameter of the power supply signal to match the RF input signal timing, the system maintains ease of operation through automated adjustment while ensuring reliability by meeting linearity and error vector magnitude requirements.
2Measurement precision
If delay measurement precision is increased to improve synchronization accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent introduces an intermediary delay measurement circuitry that indirectly measures the delay between envelope tracking power supply voltage and RF input signal by comparing their timing relationships. This intermediary measurement approach achieves high delay measurement precision without requiring direct complex synchronization hardware, as the circuitry uses accessible signal points and standard measurement techniques to derive the timing offset.
3Reliability
If delay compensation is implemented to meet linearity requirements, then linearity is improved, but device complexity increases
Solution Approach 1:
The patent merges the delay measurement functionality and delay compensation control into the existing envelope tracking power supply system. The delay measurement circuitry is integrated with the envelope tracking generator, and the compensation mechanism is combined with the existing voltage generation path. This merging approach improves linearity through delay compensation while minimizing device complexity by reusing existing circuit blocks and signal paths rather than adding completely separate systems.
Data Source
AI summary
A difference between subsequent measures of a second signal when a first signal crosses a threshold value can be used to estimate a delay between the first and second signal. The delay can be used to compensate for delays between an envelope power supply signal and a radio frequency (RF) input signal.