Envelope-Tracking Amplifier Delay Calibration Using Amplitude-Phase Alignment
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Solution Overview
Problem
Current methods for calibrating the amplitude delay in envelope-tracking amplifiers are time-consuming and inefficient, relying on trial-and-error spectral emissions testing, which requires extensive measurement time and is not suitable for real-time applications.
Innovation Solution
A receiver-based method that estimates the amplitude delay by generating a model signal, computing time delays between amplitude and phase envelopes, and compensating the transmitter's delay unit to align signals, significantly reducing calibration time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If trial-and-error spectral emissions testing is used to calibrate amplitude delay, then measurement accuracy is improved, but calibration time increases significantly
Solution Approach 1:
The patent creates a model signal that copies the expected characteristics of the transmitted signal, including its amplitude envelope and phase information. By comparing the received signal against this model, the system can directly estimate delay parameters without requiring extensive trial-and-error spectral emissions testing, thus reducing calibration time while maintaining accuracy
Solution Approach 2:
The patent replaces the mechanical trial-and-error adjustment process with a computational signal processing approach. Instead of manually or iteratively adjusting delay parameters and measuring spectral emissions, the system uses correlation-based signal processing to directly calculate the delay estimate from the received signal and model signal comparison
2Reliability
If extensive spectral emissions measurements are performed with multiple averages, then measurement reliability is improved, but productivity decreases
Solution Approach 1:
By using a model signal that replicates the expected transmitted signal characteristics, the system can perform direct delay estimation through signal correlation. This approach maintains measurement reliability by using the model as a reference while dramatically improving productivity by eliminating the need for multiple spectral emissions measurements with averaging
Solution Approach 2:
The model signal serves as an intermediary that bridges the transmitted signal and the received signal for comparison purposes. This intermediary enables direct delay estimation through correlation processing, achieving both reliable measurements and high calibration throughput without requiring extensive spectral emissions testing
Data Source
AI summary
A system and method for estimating a time delay introduced by an envelope tracking amplifier (ETA) of a transmitter. The ETA receives a first baseband signal that is generated by the transmitter and operates on the first baseband signal to produce an output signal. The receiver receives a second baseband signal in response to the transmitter's transmission of the output signal. The receiver generates a model signal that represents an estimate of the first baseband signal. The receiver computes a first time delay between the amplitude envelopes of the second baseband signal and the model signal. The receiver computes a second time delay between phase signals derived respectively from the second baseband signal and the model signal. The receiver estimates the time delay that is introduced by the ETA of the transmitter by subtracting the second time delay from the first time delay.