Frequency Change Phase Relationship Maintenance
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Solution Overview
Problem
Existing methods for frequency change in network analyzers fail to maintain the phase relationship between devices, leading to inaccuracies in measurements during frequency adjustments.
Innovation Solution
A two-step procedure is implemented, where the frequencies of local oscillators are changed first, allowing phase changes to be identified and corrected, followed by changing the signal generator frequencies, ensuring that the phase relationship is maintained during frequency changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the frequency of both local oscillators and signal generators is changed simultaneously, then the frequency change is completed efficiently, but the phase relationship between devices is lost
Solution Approach 1:
The frequency change process is segmented into two distinct steps: first changing the local oscillator frequencies while keeping signal generator frequencies constant, then changing the signal generator frequencies while keeping local oscillator frequencies constant. This segmentation allows the phase relationship to be maintained during each step while still achieving the overall frequency change objective.
2Measurement precision
If the frequency of local oscillators is changed first, then phase changes can be identified and corrected, but the frequency change process becomes more complex
Solution Approach 1:
The complex frequency change procedure is segmented into two manageable steps with clear separation of functions. Step 1 isolates local oscillator frequency changes, and Step 2 isolates signal generator frequency changes. This segmentation makes the complex process controllable and measurable.
Solution Approach 2:
The local oscillator frequency change is performed as a preliminary action before the signal generator frequency change. This preliminary action allows the system to adjust and stabilize the local oscillator frequencies first, ensuring that any phase changes observed can be attributed to known causes and corrected accordingly before the final frequency adjustment.
3Stability of the object's composition
If the frequency of signal generators is changed first, then excitation remains unchanged during local oscillator adjustment, but phase changes from device under test cannot be separated from oscillator changes
Solution Approach 1:
The frequency change process is segmented to first adjust local oscillators while maintaining stable excitation from signal generators. This allows the system to isolate and measure phase changes caused by local oscillator adjustments without the confounding variable of changing excitation frequencies. The segmentation enables clear separation of phase change sources.
Data Source
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AI summary
The invention relates to a method for carrying out a frequency change whilst retaining the phase relationship between several devices, in particular, network analysers. Each device has at least one signal generator or stimulating an object for measurement and at least one local oscillator (LOl) connected to at least one mixer (1O1) for receiving a measuring signal obtained from the object for measurement by the superposition principle. On changing frequency, in a first step (Sl) only the frequency of the local oscillators (LOl) of all devices is changed and the frequency of eth signal generators (SOl) of all devices remains unchanged. In a second step (S2) only the frequency of at least one signal generator (SOl) is changed and the frequency of the local oscillators (LOl) of all devices remains unchanged.