Transceiver Circuit Equalization for Wideband AM-AM and AM-PM Correction
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Solution Overview
Problem
Conventional methods for correcting amplitude-amplitude (AM-AM) and amplitude-phase (AM-PM) errors in wireless communication circuits require complex memory digital predistortion (mDPD) coefficients to be defined and calibrated for each modulation frequency, leading to increased complexity and inefficiency, especially in wide bandwidth applications like 5G and 5G-NR systems.
Innovation Solution
A transceiver circuit is configured to equalize input vectors using frequency equalization filters, followed by gain and phase error correction circuits to eliminate modulation frequency dependency, allowing for low-complexity correction of AM-AM and AM-PM errors across a modulation bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional memory digital predistortion (mDPD) methods are used to correct AM-AM and AM-PM errors, then correction accuracy is improved, but device complexity increases due to requiring separate coefficient calibration for each modulation frequency
Solution Approach 1:
The patent implements a universal correction approach where a single set of frequency equalization filter coefficients corrects AM-AM and AM-PM errors across all modulation frequencies within the bandwidth. Instead of requiring separate mDPD coefficient calibration for each frequency, the system uses one universal filter that handles all frequencies simultaneously, eliminating the need for frequency-specific calibration while maintaining correction effectiveness across the entire modulation bandwidth
Solution Approach 2:
The patent merges the correction functions for all modulation frequencies into a single frequency equalization filter. Rather than having separate correction mechanisms for each frequency, the system combines all correction operations into one unified filter structure that processes all frequencies together, thereby reducing the overall system complexity and eliminating the need for multiple coefficient sets
2Measurement precision
If frequency-specific coefficient calibration is performed for each modulation frequency, then correction precision is improved, but productivity decreases due to increased calibration time and processing overhead
Solution Approach 1:
The patent performs preliminary action by pre-calculating and storing a single set of frequency equalization filter coefficients that are designed to correct errors across the entire modulation bandwidth. This preliminary calculation eliminates the need for repeated real-time coefficient calibration for each frequency during operation, significantly improving calibration efficiency while maintaining correction precision through the optimized universal filter design
3Reliability
If conventional mDPD correction is applied across wide modulation bandwidth, then linearity is improved, but device complexity increases due to handling of frequency-dependent errors
Solution Approach 1:
The patent changes the approach from handling frequency-dependent errors separately to using frequency-independent correction parameters. By transforming the correction methodology to use universal filter coefficients that work across all frequencies, the system maintains signal linearity improvement while eliminating the complexity associated with managing frequency-dependent correction parameters
Data Source
AI summary
Amplitude and phase error correction in a transceiver circuit is provided. In embodiments disclosed herein, a transceiver circuit is configured to equalize an input vector to thereby correct amplitude-amplitude (AM-AM) and amplitude-phase (AM-PM) errors across a modulation bandwidth of the wireless communication circuit. Unlike conventional methods where complicated memory digital predistortion (mDPD) coefficients must be defined and calibrated for each modulation frequency within the modulation bandwidth, the transceiver circuit is configured herein to eliminate modulation frequency dependency of the AM-AM and AM-PM errors. As a result, it is possible to correct the AM-AM and AM-PM errors across the modulation bandwidth with reduced complexity to thereby improve efficiency and linearity of the wireless communication circuit.