Microwave Mixer Phase Response Measurement Using Reference Generator
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Solution Overview
Problem
Current methods for measuring the phase response of microwave mixers are prone to errors due to the complexities of frequency translation and local oscillator delays, making it difficult to achieve accurate characterization of these devices.
Innovation Solution
A system comprising a vector network analyzer, additional device, local oscillator, and switches connected to a vector voltmeter, which allows for the measurement of forward and reverse sum phase responses, enabling the calculation of the device under test's phase response independently of the local oscillator's phase response, using a reference generator for calibration and error reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement methods are used for microwave mixer phase response, then the measurement process is simple, but the measurement precision deteriorates due to local oscillator delays and frequency translation complexities
Solution Approach 1:
The measurement process is divided into separate sequential steps: measuring forward sum phase response, measuring reverse sum phase response, and calculating the device under test phase response. This segmentation allows each measurement to be performed independently without the complexity of simultaneous multi-parameter measurement, while the calculated result achieves high precision by eliminating local oscillator delay errors through mathematical processing.
2Adaptability or versatility
If additional mixers connected in series are used to measure phase response, then the measurement can be performed, but errors are introduced due to local oscillator channel delays between mixers
Solution Approach 1:
The measurement method uses feedback by measuring both forward and reverse sum phase responses and using these measurements to calculate the device under test phase response. This feedback approach allows the system to compensate for and eliminate local oscillator delay errors through mathematical processing, achieving high precision measurements of frequency translating devices.
3Measurement precision
If three known standards are connected to the mixer output for reflection measurement, then phase response can be determined, but magnitude-to-phase modulation creates errors due to magnitude differences between forward and reflected waves
Solution Approach 1:
The invention introduces an additional mixer as an intermediary device to convert the microwave signals to intermediate frequency signals. This intermediary approach allows the measurement system to avoid the magnitude-to-phase modulation errors that occur when directly measuring reflected waves at microwave frequencies, while the intermediate frequency conversion simplifies the measurement setup complexity.
Data Source
AI summary
A system, method and apparatus for mixer phase response measurement comprises a vector network analyzer connectable to a device under test, an additional device connected to the analyzer the additional device configured to have an equal phase response to that of the device under test, a local oscillator connected to the device under test and the additional device, a series of switches connecting the device under test and the additional device to a vector voltmeter, and a reference generator connected to the vector voltmeter.