Normalized Phase Spectrum Generation Using Slope Reference
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Solution Overview
Problem
Comparing phase measurements taken at different times is challenging due to variations in the starting time of the sample sequence relative to a repetitive signal, making it difficult to determine the relationship between phases as a function of frequency, especially when measuring two different frequency spectra.
Innovation Solution
A method and apparatus that generate a normalized phase spectrum using a phase slope reference signal and a signal digitizer to normalize phases independently of the starting time, utilizing a numerically controlled oscillator and controller to synchronize and combine phase spectra from multiple test signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If phase measurements are taken at different times, then measurement flexibility and productivity are improved, but phase comparison accuracy deteriorates due to time-dependent variations
Solution Approach 1:
A phase slope reference signal is introduced as an intermediary to mediate between measurements taken at different times. This reference signal provides a common reference that allows phase spectra from different measurement times to be normalized and compared accurately, eliminating the time-dependent variations that would otherwise prevent accurate comparison.
Solution Approach 2:
The phase spectra are transformed by changing the reference parameter from absolute phase values to phase values normalized relative to the phase slope reference signal. This parameter transformation enables meaningful comparison of phases across different measurement times by removing the time-dependent phase offsets.
2Ease of operation
If simple phase normalization is used, then ease of operation is improved, but reliability of phase comparison deteriorates for wideband measurements
Solution Approach 1:
The phase slope reference signal serves as a mediator that provides a reliable reference for normalizing phase spectra in wideband measurements. Unlike simple normalization methods that may not account for time-dependent variations, this intermediary reference signal enables reliable phase comparison across different measurement conditions while maintaining ease of operation.
Data Source
AI summary
A method and apparatus for generating a normalized phase spectrum from a signal having a plurality of tones is disclosed. The apparatus includes a first receiver having a first signal port adapted to receive a first test signal having a first plurality of tones and a reference port adapted to receive a phase slope reference signal includes a reference tone and generates a sequence of digital values therefrom starting from a first time. The apparatus also includes a signal digitizer that digitizes the received first test signal to generate a sequence of digitized values of the received first test signal starting at the first time and a phase spectrum generator that generates a first normalized phase spectrum that is independent of the first time from the digitized values of the received first test signal and the received phase slope reference signal.