TinyTapeout - Decimation Filter
Motivation
The rapid advancement of digital signal processing requires efficient and reliable ways of converting analog signals into high-quality digital data. Decimation filters, are essential for down sampling signals while maintaining their integrity and are crucial in analog-to-digital converters (ADCs).
Objective
Design a decimation filter for the ADC designed in ECE 628 utilizing incremental Delta-Sigma modulation. Utilizing Tiny Tapeout platform for tapeout make the manufacturing process cost-effective and accessible.
Design Execution and Testing
Incremental ΔΣ Modulation ADC:
Utilizes two integrators (accumulators), with its output synchronized to a reset signal to align with the incremental ADC’s operation.
Free-running ΔΣ Modulation ADC:
Utilizes a cascade-integrator comb (CIC) filter, consisting of two integrator parts (accumulators) and two comb parts (differentiators). The integrators’ output is passed through a comb filter, where the output is calculated as the difference between the delayed and current values.
Test Waveforms:
Final Design
Cells: 772 (excluding decoupling capacitors and filler cells)
Flip-flops: 89
Tiles: 1x1
Challenges
Making design synthesizable for ASIC implementation.
- Ensuring all variables were set to zero at the beginning of simulation (initial blocks are non-synthesizable)
Using OSS CAD Suite, binary software distribution for several open-source software used in digital logic design.
- Local hardening dependency errors when running tools for RTL synthesis
Ensuring documentation and design variables are correctly implemented to have a successful submission to Tiny Tapeout.
Design was successfully submitted to the Tiny Tapeout TT09 run.
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