RF Signal Path Characterization via Frequency Domain Analysis
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Solution Overview
Problem
Current methods for characterizing radio frequency (RF) signal processing paths are inefficient and impractical, especially in integrated RF hardware, as they require expensive instruments and tedious procedures to measure amplitude and phase variations across multiple parallel signal paths, which can lead to data integrity issues due to IQ imbalance.
Innovation Solution
A method that transforms input and output test signals from the time domain to the frequency domain to determine amplitude and phase correction coefficients for each signal processing path, allowing for simultaneous measurement of distortions across a wide frequency band using a single input test signal, and applies these corrections to pre-compensate data signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods using vector network analyzers are used to characterize RF signal processing paths, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses a digital signal processor to generate test signals and simulate the characterization process through digital signal processing, creating a virtual copy of the measurement process that avoids the need for expensive physical vector network analyzers while maintaining measurement precision
Solution Approach 2:
The patent replaces the mechanical/electrical measurement system (vector network analyzer) with a digital signal processing system that uses software algorithms to perform frequency response characterization, substituting physical measurement hardware with computational methods
2Measurement precision
If single frequency sinusoidal test signals are swept across the frequency band to characterize signal paths, then measurement precision is improved, but productivity deteriorates
Solution Approach 1:
The patent uses spread spectrum test signals that contain all frequency components simultaneously rather than sweeping through frequencies sequentially, enabling parallel measurement of the entire frequency band in a single operation rather than through repeated periodic measurements at individual frequencies
Solution Approach 2:
The patent pre-modulates the test signal with a known spread spectrum sequence before transmission, allowing the receiver to correlate and extract frequency response information for all frequencies simultaneously from a single transmitted signal, eliminating the need for sequential frequency sweeping
3Measurement precision
If multiple parallel signal processing paths are characterized individually, then measurement precision is improved, but time consumption increases
Solution Approach 1:
The patent combines multiple path characterization measurements into a single simultaneous operation by using orthogonal test signals for different paths that can be transmitted and received together, then separated through correlation processing, allowing parallel characterization of multiple signal paths without sequential measurement
Solution Approach 2:
The patent designs a universal test signal structure that can simultaneously characterize multiple different signal processing paths by incorporating orthogonal sequences for each path, allowing a single measurement setup to perform multiple characterization functions concurrently
4Measurement precision
If accurate time and phase synchronisation is implemented between test signal generator and detector, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent uses the known spread spectrum test signal sequence as a reference for correlation processing at the receiver, automatically establishing time and phase synchronization through the correlation peak without requiring external synchronization hardware or complex control systems
Solution Approach 2:
The test signal itself contains embedded synchronization information through its known spread spectrum sequence, allowing the measurement system to self-synchronize without external timing references or complex synchronization hardware, with the signal structure providing its own timing and phase reference
Data Source
AI summary
A method for determining amplitude and phase correction coefficients for one or more signal processing paths across a frequency band of interest is provided. The method comprises transforming an input test signal from the time domain to the frequency domain to obtain an input magnitude spectrum and an input phase spectrum for the/each signal processing path. It further comprises transforming an/each respective output test signal from the time domain to the frequency domain to obtain an output magnitude spectrum and an output phase spectrum for the/each signal processing path. It also comprises comparing the/each input magnitude spectrum with its respective output magnitude spectrum to determine an amplitude correction coefficient for the/each signal processing path and/or comparing the/each input phase spectrum with its respective output phase spectrum, to determine a phase correction coefficient for the or each signal processing path.