Variable Attenuator Calibration via Internal and External Signal Paths
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Solution Overview
Problem
Existing signal generation apparatuses face challenges in obtaining accurate correction values for variable attenuators due to the influence of non-linearity in semiconductor components on the signal path, especially when the gain of the signal generation unit is significantly changed.
Innovation Solution
A signal generation apparatus with a switch that routes the signal through internal and external paths to calculate step error values for variable attenuators, using the internal path for attenuators less affected by impedance changes and the external path for those greatly affected, allowing for precise correction value calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the gain of the signal generation unit is greatly changed to obtain correction values, then the correction range is improved, but the non-linearity of semiconductor components increases and measurement accuracy deteriorates
Solution Approach 1:
The patent divides the correction process into two independent paths: an internal path for attenuators less affected by impedance changes and an external path for those greatly affected. This segmentation allows each path to be optimized independently, enabling accurate correction across the full gain range without being limited by semiconductor non-linearity in a single measurement path.
Solution Approach 2:
The patent introduces a switch as an intermediary component that routes the signal through different paths (internal or external) depending on the attenuator's characteristics. This intermediary enables the system to bypass the semiconductor component non-linearity issue by selecting the appropriate measurement path, thereby maintaining high correction accuracy across the full adaptation range.
2Device complexity
If a single measurement path is used for all variable attenuators, then the device complexity is reduced, but the measurement accuracy deteriorates due to impedance changes affecting different attenuators differently
Solution Approach 1:
The patent implements a dynamic measurement system where the switch can route signals through different paths based on the specific attenuator being measured. This dynamic configuration allows the system to adapt the measurement path to match the attenuator's impedance characteristics, ensuring high accuracy without requiring a completely complex fixed multi-path structure.
Solution Approach 2:
The patent applies different measurement approaches (internal vs. external path) to different variable attenuators based on their individual characteristics. Rather than using a uniform measurement method for all attenuators, the system tailors the measurement path to each attenuator's impedance properties, thereby achieving high precision while maintaining reasonable system complexity.
Data Source
AI summary
A signal generation unit 2, a DA converter 3, variable attenuators 40, 42, 44, and 46, a measurement unit 6 that detects a level of the signal attenuated by the variable attenuators 40, 42, 44, and 46 and passed through one or more semiconductor components, a switch 48 that switches between an Internal path through which the signal attenuated by the variable attenuator 40, 42, 44, and 46 is transmitted to the measurement unit 6 and an External path through which the signal attenuated by the variable attenuator 40, 42, 44, and 46 is output from an output terminal 10, and a control unit 7 that obtains a correction value of an attenuation amount of the variable attenuators 40, 42, and 44 with the Internal path and obtains a correction value of an attenuation amount of the variable attenuator 46 with the External path.