Offset-Free Sinc Interpolator With Periodic Integrator Reset
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Solution Overview
Problem
Sinc interpolators face issues with offset errors due to word retention and quantization errors, especially in higher-order filters, which can lead to distorted outputs and data loss when trying to reset integrators during operation.
Innovation Solution
An offset-free sinc interpolator design that includes differentiators, integrators, and coefficient multipliers, where integrators are reset periodically before each input cycle, minimizing offset and quantization errors by using different sampling frequencies and resetting delay elements to zero.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If integrators are continuously operated to maintain signal processing, then signal processing continuity is improved, but offset errors accumulate due to word retention
Solution Approach 1:
The patent applies periodic resetting of integrators at specific intervals (every N input samples) to eliminate offset errors while maintaining overall signal processing continuity. This periodic action prevents error accumulation without requiring continuous interruption of the signal processing chain.
Solution Approach 2:
The patent performs preliminary resetting of integrators before offset errors can significantly accumulate and distort the output signal. By proactively resetting at predetermined intervals, the system prevents error buildup rather than correcting it after the fact.
2Measurement precision
If integrators are reset during operation to minimize offset errors, then offset error accumulation is reduced, but data loss occurs and output distortion increases
Solution Approach 1:
The patent implements periodic resetting at carefully chosen intervals (every N input samples) that align with the signal processing cycle, ensuring that resetting occurs at optimal moments that minimize data loss and output distortion while still effectively reducing offset errors.
Solution Approach 2:
The patent changes the operating parameters of the integrators by resetting their initial conditions periodically, allowing them to maintain accurate operation over extended periods without suffering from cumulative offset errors, thereby preventing data loss and distortion.
3Measurement precision
If higher order interpolators are used to improve interpolation accuracy, then interpolation precision is improved, but output distortion increases due to offset and quantization errors
Solution Approach 1:
The patent applies periodic resetting to higher order interpolators to prevent offset and quantization errors from accumulating and causing output distortion, thereby maintaining the high interpolation accuracy that higher order filters provide without suffering from error accumulation.
Solution Approach 2:
The patent modifies the operational parameters of higher order interpolators by implementing periodic resets, which eliminates the harmful effect of error accumulation while preserving the enhanced interpolation accuracy that higher order filters provide.
4Reliability
If sampling rate is increased through interpolation to improve signal reconstruction, then signal quality is improved, but quantization errors increase due to discrete value assignments
Solution Approach 1:
The patent changes the initial condition parameters of the integrators periodically, which helps to minimize quantization errors that arise during high-rate sampling and interpolation, thereby maintaining signal reconstruction quality without excessive quantization distortion.
Data Source
AI summary
An offset free sinc interpolating filter includes differentiators operating at a first sampling frequency, integrators operating at a second sampling frequency and one or more coefficient multipliers. The coefficient multipliers multiply a received value with a constant coefficient value to generate an output value. The differentiators, integrators and coefficient multipliers can be operatively coupled to each other, either directly or through other components such as adders and delay elements, or by a combination of the two. In operation, an input signal is provided to the sinc interpolating filter at the first sampling frequency. The input signal is processed by the differentiators, integrators and coefficient multipliers to generate an output signal at the second sampling frequency. Once the output signal is generated, the integrators are reset before the next input cycle begins.