Phase Frequency Response Measurement Across Switchable DUT Configurations
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Solution Overview
Problem
Conventional methods for measuring phase frequency response in signal conversion devices, such as analog to digital converters, are limited by the need for matching input and output frequencies and analog ports, making them unsuitable for devices like ADCs, and require complex setups and time-consuming measurements with varying signal levels, which restrict their practical application.
Innovation Solution
A method that selects a reference configuration for phase and amplitude measurements, calculates the minimum-phase difference for other configurations, and uses this difference to derive the phase frequency response, allowing for measurements with a constant test signal generator and reducing the need for frequent setup changes and long measurement times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional VNA-based methods are used for phase frequency response measurement, then measurement precision can be achieved for devices with matching analog ports, but the method becomes inapplicable to signal conversion devices like ADCs with different input and output port types
Solution Approach 1:
The patent introduces an intermediary processing stage that converts digital output signals back to analog form for phase comparison, enabling measurement in ADCs. The digital signal is converted to analog through a digital-to-analog converter, then mixed with the original analog input signal to extract phase information, thus bridging the gap between different port types.
Solution Approach 2:
The patent replaces the traditional VNA analog measurement system with a digital signal processing approach. Instead of using analog network analyzer components, the invention uses digital sampling, computational algorithms, and software-based phase extraction to achieve phase frequency response measurement, thereby adapting the measurement capability to digital devices.
2Adaptability or versatility
If amplifier or attenuator substitutions are made to accommodate different input signal levels, then the DUT can handle varying signal levels, but the frequency response changes and requires re-measurement
Solution Approach 1:
The patent performs preliminary characterization of the DUT across all configurations before actual measurements. By pre-measuring and storing the frequency response of each configuration, the system avoids the need to re-measure when switching configurations, thereby maintaining measurement precision while accommodating varying signal levels.
Solution Approach 2:
The patent systematically varies the configuration parameters (amplifier gains, attenuator settings) and measures the corresponding frequency responses. By establishing the relationship between configuration parameters and frequency response characteristics, the system can accurately compensate for changes when switching between different input signal level configurations.
3Adaptability or versatility
If multiple test signals with wide frequency range and large dynamic range are generated, then amplitude frequency response can be measured for different configurations, but construction of such generator becomes technically difficult
Solution Approach 1:
The patent divides the frequency range into multiple discrete frequency points rather than attempting to generate a continuous wideband signal. By segmenting the measurement into individual frequency sweeps at different configurations, the system achieves comprehensive coverage without requiring a complex wideband signal generator with large dynamic range capabilities.
4Measurement precision
If phase frequency response measurement is performed for multiple DUT configurations, then complete characterization is achieved, but measurement time becomes excessively long
Solution Approach 1:
The patent performs preliminary measurement of all DUT configurations and stores the results for later use. This pre-characterization approach allows the system to quickly retrieve pre-measured frequency response data when switching between configurations, eliminating the need for repeated measurements and significantly reducing measurement time while maintaining complete characterization.
Data Source
AI summary
A measurement of phase frequency response of a device under test (DUT), wherein the DUT is characterized by a set of switchable configurations, comprises choosing the steps of a particular configuration of the DUT having nominal parameters as a reference configuration, measuring an amplitude frequency response Aref (f) and a phase frequency response ϕref(f) of the reference configuration, processing all configurations of the DUT which are different from the reference configuration, one after another, by measuring an amplitude response A(f) of the configuration being processed, calculating a minimum phase difference response Δϕmin(f); and calculating for each configuration, a phase frequency response ϕ(f) of the respective configuration which is being processed, in accordance with ϕ(f)=ϕref(f)+Δϕmin(f).