DAC Echo Calibration Using Odd-Even Offset Mapping
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Solution Overview
Problem
Digital-to-analog conversion apparatuses face errors due to current source offsets and echo generation from transmission path mismatches, requiring effective calibration mechanisms to improve conversion results.
Innovation Solution
A digital-to-analog conversion apparatus with a signal calibration mechanism, comprising a digital-to-analog conversion circuit, an echo transmission circuit, an echo calibration circuit, and a calibration parameter calculation circuit, which operates at a second frequency half of the first frequency to perform down-sampling, mapping, and coefficient convergence for echo cancellation and offset correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a digital-to-analog conversion apparatus is used to convert digital signals to analog signals, then signal conversion functionality is provided, but errors are generated due to offsets of current sources and echoes are generated due to transmission path mismatch
Solution Approach 1:
The patent applies preliminary action by performing calibration operations before actual signal conversion. The calibration module pre-calibrates the current sources and transmission paths by storing calibration data that compensates for offsets and mismatches, ensuring accurate conversion without requiring real-time correction during signal processing
Solution Approach 2:
The patent implements feedback mechanisms where the calibration module continuously monitors conversion errors and echoes, then adjusts the calibration data accordingly. This closed-loop feedback system reduces current source offsets and transmission path mismatches by using error signals to update compensation parameters, thereby improving both conversion accuracy and signal quality
2Measurement precision
If calibration mechanisms are added to reduce errors and echoes, then conversion accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges the calibration functionality with the existing digital-to-analog conversion circuitry by integrating the calibration module into the signal processing path. This allows calibration operations to share hardware resources with normal conversion operations, reducing overall device complexity while maintaining conversion accuracy
Solution Approach 2:
The calibration module is designed to perform multiple functions: it calibrates current sources, compensates for transmission path mismatches, and generates correction signals for both differential and single-ended output modes. This multi-functional approach reduces the need for separate calibration circuits, thereby limiting the increase in device complexity
Data Source
AI summary
The present invention discloses a digital-to-analog conversion apparatus having signal calibration mechanism. A DAC circuit includes conversion circuits to generate an output analog signal and an echo-canceling analog signal. An echo transmission circuit performs signal processing on an echo path to generate an echo signal. An echo calibration circuit includes odd and even calibration circuits to perform mapping according to offset tables and perform processing according to response coefficients on odd and even input parts of an input digital signal to generate odd and even calibration parts of an echo-canceling calibration signal. A calibration parameter calculation circuit generates offsets according to an error signal between the echo signal and the echo-canceling calibration signal and path information related to the echo calibration circuit. The echo calibration circuit makes the coefficients converge according to the error signal and pseudo noise transmission path information, and updates the offset tables according to the offset.