CIC Decimation Filter with PLL-Controlled Variable Rate
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Solution Overview
Problem
Existing decimation filters are not capable of dynamically adjusting their decimation rates in response to varying sample rates over time, which limits their effectiveness in applications requiring different decimation rates at different times.
Innovation Solution
A system and method utilizing a cascade integrator comb (CIC) decimation filter with a digital phase lock loop to control the decimation rate, allowing for real-time or near-real-time adjustments of the decimation rate based on changing sample rate conditions, achieved through a controller that provides a decimation rate adjustment signal to the filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed decimation rate is used in the decimation filter, then the filter structure is simple and stable, but the filter cannot adapt to varying sample rates over time
Solution Approach 1:
The decimation filter employs a variable decimation rate mechanism where the decimation factor can be dynamically adjusted based on the sample rate of the input digital signal. The filter structure includes a decimation module that responds to control signals from a digital phase lock loop, enabling the system to adapt to different sample rates by changing the decimation rate in real-time rather than being fixed
Solution Approach 2:
The invention changes the operational parameter of the decimation filter by allowing the decimation rate to vary. The digital phase lock loop generates control signals that adjust the decimation rate parameter based on detected sample rate conditions, enabling the filter to maintain optimal performance across different operating conditions without requiring a completely different filter structure
2Adaptability or versatility
If the decimation rate is adjusted dynamically, then the filter can match changing sample rates, but the control system complexity increases
Solution Approach 1:
The system implements a feedback mechanism through a digital phase lock loop that continuously monitors the sample rate of the input signal and generates appropriate control signals to adjust the decimation rate. This closed-loop control ensures that the decimation filter adapts automatically to changing sample rates without requiring complex external control logic
Solution Approach 2:
The digital phase lock loop serves multiple functions: it detects the sample rate of the input signal, generates control signals for the decimation module, and potentially provides other synchronization functions. This multi-functionality reduces the need for separate dedicated control circuits, thereby limiting the increase in overall system complexity
Data Source
AI summary
A system includes a decimation module having an adjustable decimation rate and a filter module responsive to the decimation module. A digital phase lock loop is operable to control a decimation rate of the decimation module. The decimation module is a cascade integrator comb decimation module.