Phase Noise Measurement for Periodically Modulated Signals
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Solution Overview
Problem
Traditional methods for determining phase noise are inadequate for modulated signals, particularly in applications like FMCW radar, where the signal is periodically modulated and direct measurement is not feasible due to integration constraints or the need to account for modulation effects.
Innovation Solution
A method and device that process the modulated signal to determine its period and type of modulation, allowing for demodulation to a continuous wave form, enabling the application of traditional phase noise measurement techniques to quantify phase noise in periodically modulated signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional CW measurement methods are used, then measurement simplicity is maintained, but measurement precision deteriorates because these methods assume constant frequency and cannot handle modulated signals
Solution Approach 1:
The patent applies preliminary action by first determining the modulation type and period of the modulated signal before performing phase noise measurement. The method includes: determining modulation type from the modulated signal, determining modulation period based on the modulation type, compensating the modulated signal using the determined modulation type and period to obtain a compensated signal, and then performing phase noise measurement on the compensated signal. This preliminary analysis and compensation enables accurate phase noise measurement of modulated signals that would otherwise be impossible with traditional CW methods.
2Measurement precision
If direct measurement of modulated signals is attempted, then measurement speed is maintained, but measurement precision deteriorates due to the inability to account for modulation effects on phase noise
Solution Approach 1:
The patent performs preliminary determination of modulation type and period, followed by signal compensation before phase noise measurement. While this adds processing steps, it enables accurate measurement that would otherwise be impossible, and the automated nature of the process minimizes manual intervention time.
3Measurement precision
If modulation effects are accounted for through demodulation, then measurement precision improves, but device complexity increases due to additional processing requirements
Solution Approach 1:
The patent extracts the modulation characteristics (modulation type and period) from the modulated signal and uses them to compensate for modulation effects. By determining the modulation type through signal analysis and extracting the period information, the method isolates and removes the modulation component's influence on phase noise measurement, enabling accurate measurement of the underlying carrier signal's phase noise.
Solution Approach 2:
The patent changes the signal parameters by compensating the modulated signal using the determined modulation type and period. This compensation process transforms the modulated signal into a compensated signal where modulation effects are removed or minimized, allowing traditional phase noise measurement techniques to be applied accurately to the compensated signal.
Data Source
AI summary
A method for determining phase noise in a periodically modulated signal is described. The modulated signal is processed to generate a processed signal from the modulated signal. At least an approximate period of a modulation of the modulated signal is determined from the processed signal. The type of modulation of the modulated signal is determined from the processed signal. The modulated signal is demodulated based on the determined period and the determined type of modulation to generate a demodulated signal, and the phase noise is determined from the demodulated signal. Moreover, a measurement device is described.