IF Phase Dispersion Characterization Without Calibration
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Solution Overview
Problem
Existing methods for characterizing the intermediate frequency (IF) phase dispersion characteristics of frequency translating receivers, such as superheterodyne receivers, are inefficient and require calibrated RF and LO channel responses, which can be time-consuming and impractical.
Innovation Solution
A method and system that generate a test signal with specific RF frequencies and use a local oscillator to convert it to an IF signal, filtering and measuring the IF output at various frequencies to ascertain phase dispersion, without the need for calibrated RF and LO channel responses, by setting the LO frequency to specific values and measuring the filtered IF output signal at corresponding IF frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing methods are used to characterize IF phase dispersion, then measurement accuracy can be achieved, but the process is time-consuming and requires calibrated RF and LO channel responses
Solution Approach 1:
The patent extracts and eliminates the requirement for calibrated RF and LO channel responses from the measurement process. By using a mathematical model that relates IF phase dispersion to measurable quantities (IF amplitude and phase at specific frequencies), the method removes the time-consuming calibration step while maintaining measurement accuracy.
Solution Approach 2:
The patent creates a mathematical copy or model of the IF channel response that can be measured without actual physical calibration. The model uses relationships between signal components at different frequencies to represent the calibrated response, allowing accurate characterization without time-consuming physical calibration procedures.
2Measurement precision
If existing methods are used to characterize IF phase dispersion, then measurement accuracy can be achieved, but the process is complex and impractical
Solution Approach 1:
The patent simplifies the measurement system by extracting and removing the complex calibration procedures and RF/LO channel response requirements. The method uses only basic measurements of IF signal amplitude and phase at specific frequencies, significantly reducing system complexity while maintaining accuracy.
Solution Approach 2:
The patent changes the measurement approach from requiring calibrated channel responses to measuring specific parameters (amplitude and phase at defined frequencies). This parameter transformation simplifies the measurement process and reduces system complexity while achieving the same measurement goal.
3Productivity
If efficient characterization methods are implemented, then measurement time is reduced, but measurement accuracy may be compromised
Solution Approach 1:
The patent uses mathematical relationships that provide feedback between measured quantities and the desired phase dispersion characteristic. By measuring IF amplitude and phase at specific frequencies and applying the derived relationships, the method efficiently obtains accurate phase dispersion values without time-consuming calibration.
Solution Approach 2:
The patent transforms the measurement problem into a parameter calculation problem. Instead of requiring time-consuming calibration measurements, the method uses mathematical parameter relationships to efficiently compute phase dispersion from simple IF signal measurements, maintaining accuracy while improving efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient and accurate characterization of IF phase dispersion characteristics, allowing for precise measurement of phase dispersion values across different IF frequencies, improving measurement efficiency and reducing the need for extensive calibration.
Implementation Method 1
using a local oscillator (LO) signal to convert the test signal to an intermediate frequency (IF) signal
Data Source
AI summary
A system and method supply a test signal having a first tone at a first RF frequency and a second tone at a second RF frequency to a frequency converter; provide a local oscillator (LO) signal to the frequency converter, wherein an IF output signal of the frequency converter is supplied to an input of an intermediate frequency (IF) filter, in response to which the IF filter provides a filtered IF output signal; for each of N>1 different LO frequencies, measure the filtered IF output signal at a pair of IF frequencies corresponding to differences between the first and second RF frequencies and the LO frequency, where the measurements of the filtered IF output signal measure time-invariant phase; and ascertain N−1 values of phase dispersion D of the IF filter at N−1 corresponding IF frequencies from the N measurements of the filtered IF output signal at the N different LO frequencies.