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arXiv · 2507.00755

LearnAFE: Circuit-Algorithm Co-design Framework for Learnable Audio Analog Front-End

Jinhai Hu·Zhongyi Zhang·Cong Sheng Leow·Wang Ling Goh·Yuan Gao
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Abstract

This paper presents a circuit-algorithm co-design framework for learnable analog front-end (AFE) in audio signal classification. Designing AFE and backend classifiers separately is a common practice but non-ideal, as shown in this paper. Instead, this paper proposes a joint optimization of the backend classifier with the AFE's transfer function to achieve system-level optimum. More specifically, the transfer function parameters of an analog bandpass filter (BPF) bank are tuned in a signal-to-noise ratio (SNR)-aware training loop for the classifier. Using a co-design loss function LBPF, this work shows superior optimization of both the filter bank and the classifier. Implemented in open-source SKY130 130nm CMOS process, the optimized design achieved 90.5%-94.2% accuracy for 10-keyword classification task across a wide range of input signal SNR from 5 dB to 20 dB, with only 22k classifier parameters. Compared to conventional approach, the proposed audio AFE achieves 8.7% and 12.9% reduction in power and capacitor area respectively.

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Jinhai Hu, Zhongyi Zhang, Cong Sheng Leow, Wang Ling Goh, Yuan Gao. 2025-07-01. LearnAFE: Circuit-Algorithm Co-design Framework for Learnable Audio Analog Front-End. https://doi.org/10.1109/tcsi.2025.3578606

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