Digital-to-Analog Converter Signal Calibration Mechanism
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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, necessitating effective calibration mechanisms to improve conversion results.
Innovation Solution
A digital-to-analog conversion apparatus with a signal calibration mechanism, comprising a conversion circuit, an echo transmission circuit, an echo calibration circuit, and a calibration parameter calculation circuit, which performs down-sampling, pseudo noise feeding, and offset table updates to calibrate the echo canceling mechanism without an additional pseudo noise source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital-to-analog conversion is performed using current sources, then conversion functionality is achieved, but errors are generated due to current source offsets
Solution Approach 1:
The patent performs preliminary calibration by generating calibration signals through the conversion circuit, capturing echo signals through the transmission path, and calculating compensation parameters before actual signal conversion. This preliminary action characterizes the transmission path and current source offsets, enabling error compensation during normal operation.
Solution Approach 2:
The patent implements a feedback mechanism where echo signals returning through the transmission path are captured and used to calculate compensation parameters. These parameters are then applied to correct subsequent conversion signals, creating a closed-loop system that continuously reduces errors from current source offsets and transmission path mismatches.
2Object-generated harmful factors
If echo calibration is performed to reduce transmission path mismatch, then echo signals are reduced, but additional calibration circuits and processing are required
Solution Approach 1:
The patent makes the conversion circuit serve multiple functions: it performs both normal digital-to-analog conversion and generates calibration signals for echo calibration. The same conversion circuit is used to generate both signal feeding for normal operation and calibration signal feeding for characterization, eliminating the need for separate calibration hardware.
Solution Approach 2:
The system performs self-calibration by using its own conversion circuit and transmission path to generate and capture calibration signals. The echo calibration circuit uses the system's existing components (conversion circuit, transmission path, echo signal capture) to characterize and compensate for its own mismatches, reducing the need for external calibration equipment.
3Device complexity
If down-sampling is performed on echo path to generate lower frequency echo signal, then processing complexity is reduced, but frequency transformation is required
Solution Approach 1:
The patent changes the frequency parameter of the echo signal by performing down-sampling, transforming the high-frequency echo signal into a lower-frequency signal. This parameter change reduces the processing requirements and allows the use of lower-speed, less complex processing circuits while maintaining calibration accuracy.
Data Source
AI summary
The present disclosure discloses a digital-to-analog conversion apparatus having a signal calibration mechanism. A conversion circuit performs digital-to-analog conversion on a digital signal to generate an output analog signal. An echo transmission circuit performs down-sampling on an echo path that the output analog signal passes through to generate an echo signal. Selected data and non-selected data included in N input parts of the input digital signal are treated as a pseudo-noise input and a signal input by N calibration circuits in an echo calibration circuit so as to be mapped by codeword offset tables and processed by groups of response coefficients to generate N calibration parts of a calibration signal. A calibration parameter calculation circuit generates offsets according to the echo signal, converges the response coefficients according to an error signal and pseudo noise transmission path information and updates the codeword offset tables accordingly.