Communication Circuit Linearity Evaluation Without EVM Demodulation
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Solution Overview
Problem
Conventional methods for evaluating error vector magnitude (EVM) in radio communications require numerous sampling points, leading to increased calculation time, high processing requirements, and costly demodulators, while also lacking reliability in distortion correction and EVM standard compliance.
Innovation Solution
A method that calculates EVM by integrating amplitude and phase distortions weighted by a probability density function, eliminating the need for multiple sampling points and demodulators, allowing for EVM evaluation without demodulation processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional EVM evaluation methods using multiple sampling points are employed, then measurement precision is improved, but calculation time and device complexity increase
Solution Approach 1:
The patent extracts only the essential distortion information (amplitude and phase distortions) from the signal, eliminating the need for extensive sampling and demodulation processes. By focusing on extracting specific distortion parameters rather than processing complete signal samples, the calculation time is significantly reduced while maintaining measurement precision.
Solution Approach 2:
The patent performs preliminary determination of amplitude and phase distortions before final EVM calculation. This preliminary action allows the system to prepare distortion data in advance, which can then be used for efficient integration without requiring real-time processing of numerous sampling points, thereby reducing calculation time.
2Measurement precision
If conventional EVM evaluation methods with numerous sampling points are used, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts only the necessary distortion parameters (amplitude and phase) from the signal, eliminating the need for complex demodulators and extensive sampling infrastructure. This extraction approach maintains measurement precision while significantly simplifying the device architecture and processing requirements.
Solution Approach 2:
The patent uses integration to create a mathematical representation of the EVM value based on amplitude and phase distortions, rather than physically processing numerous signal samples. This mathematical copying approach replaces complex hardware processing with simpler computational integration, reducing device complexity while preserving measurement accuracy.
3Loss of time
If integration weighted by probability density function is used, then calculation time is reduced, but measurement precision may be compromised
Solution Approach 1:
The patent changes the parameter representation from discrete sampling points to continuous distortion functions weighted by probability density. By transforming the calculation from summing discrete error vectors to integrating continuous amplitude and phase distortions with PDF weighting, the system achieves faster calculation while maintaining precision through proper statistical representation of signal variations.
Solution Approach 2:
The patent creates a mathematical model that copies the statistical essence of multiple samples through probability density function weighting. This mathematical copying allows the integration of amplitude and phase distortions to represent the cumulative effect of numerous sampling points without actually processing those samples, thereby reducing calculation time while preserving measurement precision.
Data Source
AI summary
An evaluation method for linearity evaluations neither performing calculations of error vectors at multiple sampling points nor using a demodulator corresponding to a desired modulation scheme. Measuring devices (164 and 165) measure the input signal and the output signal of an evaluation object (1), to which a predetermined evaluation signal has been inputted. An evaluation unit (166) uses the input signal and the output signal of the evaluation object (1), to determine at least one of an amplitude distortion or a phase distortion of the output signal. An integration unit (169) uses the distortions to perform the integrations weighted by the probability density function of the power-to-average ratio of a predetermined modulated signal. A linearity index calculation unit (170) calculates a linearity index from the results of processing by the integration unit (169).