Higher-Order CIC Filter Correction for Variable Sampling Intervals
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Solution Overview
Problem
CIC filters are limited to constant sampling interval lengths, which restricts their application in variable sampling interval scenarios, such as in communication protocols for automotive sensor interfaces, where higher-order filters are needed for improved resolution but cannot be efficiently used due to fixed sampling constraints.
Innovation Solution
A device with a CIC filter of nth order, featuring a series of integrators and correction calculators, allows for the correction of integration errors by transmitting stored signal values in response to control signals, enabling the use of higher-order filters with variable sampling intervals by interrupting integration and managing memory overflow through separate memory and counter mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CIC filters of higher order are used to improve resolution, then measurement precision is improved, but the filter can only be used with constant sampling interval lengths, reducing adaptability
Solution Approach 1:
The patent implements dynamic control of the CIC filter by introducing a control signal that can interrupt the integration process at integrators. This allows the filter to adapt to variable sampling interval lengths while maintaining higher-order configurations, resolving the contradiction between using higher-order filters for improved resolution and the need for adaptability to variable sampling intervals.
2Adaptability or versatility
If CIC filters are adapted for variable sampling interval lengths, then adaptability is improved, but integration errors occur that require correction mechanisms
Solution Approach 1:
The patent employs feedback mechanisms through correction calculators that receive control signals and generate correction values based on stored signal values from integrators. These correction values are fed back to correct integration errors, maintaining reliability and accuracy while enabling adaptability to variable sampling intervals.
Solution Approach 2:
The patent stores signal values in the memories of integrators before variable sampling intervals occur. This preliminary storage allows correction calculators to retrieve these values and compute appropriate corrections in advance or in real-time, preventing integration errors from propagating and maintaining accuracy during variable sampling operations.
3Adaptability or versatility
If memories of integrators are deleted to enable variable sampling, then adaptability is improved, but signal values are lost that could be used for correction
Solution Approach 1:
The patent extracts the necessary signal values from integrator memories at appropriate moments before variable sampling intervals begin. These extracted values are transferred to correction calculators or other storage locations where they can be used for error correction without being lost when the integrator memories are deleted to enable variable sampling flexibility.
Data Source
AI summary
A device for signal processing includes a signal input, a control input, and a CIC filter of an nth order for filtering the input signal. The CIC filter includes n integrators, which are disposed one behind the other and include a memory in each case, and n is greater than one. For each of n−1 first integrators, the device includes an associated correction calculator for correcting an integration error using at least one signal value stored in the memory of the respective first integrator. The device transmits these stored signal values in response to the control signal to the associated correction calculators and to delete the memory of the remaining last integrator. Either the memories of the n−1 first integrators are also deleted, or the device includes a further correction calculator and the signal values are transmitted in response to the control signal also to the further correction calculator.