Stepwise Signal Correction Using Code Mapping for Non-Linearity
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Solution Overview
Problem
Multi-stage stepwise signal modification circuits, such as digital step attenuators and phase shifters, suffer from accuracy errors due to imperfections in stages, leading to signal distortion and non-linearity, which are difficult to correct without redesigning the circuits, especially across varying conditions like frequency and temperature.
Innovation Solution
The solution involves sorting actual values to generate a monotonic listing, mapping input codes to new codes corresponding to these values, and providing mapping functionality to convert input codes into mapped output codes, either by reordering or finding closest actual values to ideal values, thus correcting accuracy errors without redesigning the circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multi-stage stepwise signal modification circuits are used to provide discrete signal modification, then signal control capability is improved, but accuracy errors and non-linearity increase due to stage imperfections
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal code mappings in lookup tables before operation. During runtime, the system simply retrieves pre-computed correction codes based on measured conditions (temperature, frequency), avoiding complex real-time calculations and achieving both accuracy and speed.
Solution Approach 2:
The patent changes parameters by adjusting the control codes based on measured environmental conditions (temperature, frequency). The system measures actual conditions and transforms the standard control codes into corrected codes that compensate for condition-dependent errors, maintaining accuracy across varying parameters.
2Measurement precision
If circuit redesign is performed to correct accuracy errors, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent introduces an intermediary correction circuit between the control signal source and the multi-stage signal modification circuit. This intermediary contains lookup tables and control logic that translate standard control codes into corrected codes, compensating for circuit imperfections without modifying the original signal modification circuitry.
Solution Approach 2:
The patent creates a virtual model of the circuit's error characteristics through characterization data and uses this model to generate correction codes. Instead of physically redesigning the circuit, the system copies the error patterns and applies inverse corrections through software-based code transformation.
3Manufacturing precision
If circuit redesign is performed to correct accuracy errors, then manufacturing precision is improved, but loss of time and productivity decrease
Solution Approach 1:
The patent performs preliminary characterization of the circuit's error behavior once during manufacturing or setup, storing the results in lookup tables. This one-time preliminary action captures all condition-dependent errors, allowing rapid correction during operation without repeated redesign cycles for different conditions.
Solution Approach 2:
The patent enables the same circuit to operate accurately across multiple conditions (temperature, frequency) by dynamically changing the control codes based on measured parameters. This eliminates the need to redesign the circuit for each condition, saving significant development and manufacturing time.
4Device complexity
If standard control codes are used without correction, then device simplicity is maintained, but signal distortion and non-linearity increase
Solution Approach 1:
The patent inserts an intermediary code conversion stage that translates simple standard control codes into corrected codes. This intermediary layer maintains the simplicity of the control interface while eliminating signal distortion by applying condition-based corrections transparently between the control signal and the signal modification circuit.
Data Source
AI summary
Circuits and methods for correction of errors in multi-stage stepwise signal modification circuits. Embodiments of the invention also provide flexibility to correct accuracy errors over a range of conditions, such as differences in signal frequency and/or temperature. A first embodiment includes sorting actual values of a multi-stage stepwise signal modification circuit to generate a monotonic listing of actual values; mapping input codes to a new order of codes corresponding to the sorted actual values; and providing mapping functionality to convert each input code into a mapped output code. A second embodiment includes searching, for each ideal value corresponding to an input code, all actual values of a multi-stage stepwise signal modification circuit for the actual value closest to the ideal value; mapping input codes to a new order of codes corresponding to the closest actual values; and providing mapping functionality to convert each input code into a mapped output code.