Area/Energy-Efficient Gammatone Filters Based on Stochastic Computation
Area/Energy-Efficient Gammatone Filters Based on Stochastic Computation
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DOI：
10.1109/tvlsi.2017.2687404
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发表时间：
2017-04
影响因子：
2.8
通讯作者：
N. Onizawa;S. Koshita;S. Sakamoto;M. Abe;M. Kawamata;T. Hanyu
中科院分区：
文献类型：
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作者：
N. Onizawa;S. Koshita;S. Sakamoto;M. Abe;M. Kawamata;T. Hanyu
本文介绍了基于随机计算的面积/能量有效的gammatone滤波器。γ音滤波器很好地表达了人类听觉外围机制的性能，具有改进先进语音通信系统的潜力，特别是听力辅助设备和噪声鲁棒性语音识别系统。使用随机计算，数字滤波器中使用的功耗和面积饥饿的乘法器被一个简单的逻辑门所取代，从而实现了面积高效的硬件。然而，随机伽马色调滤波器的直接实现方式在计算中遭受显著低的精度，这由于滤波器增益的小值而导致低动态范围（最大与最小幅度的比率）。为了提高计算精度，提出了增益平衡技术，将原始增益表示为在二阶部分引入的多个较大增益的乘积。此外，提出了动态缩放技术，仅在随机域上放大小值，以减少所需的随机比特数，同时保持计算精度。性能比较，建议的随机伽玛滤波器的设计和评估台湾半导体制造公司（TSMC）65纳米CMOS工艺。其结果是，所提出的滤波器实现了90.7%的面积减少和91.8%的能量减少相比，在相同的采样频率和可比的动态范围与定点伽玛滤波器。
This paper introduces area/energy-efficient gammatone filters based on stochastic computation. The gammatone filter well expresses the performance of human auditory peripheral mechanism and has a potential of improving advanced speech communications systems, especially hearing assisting devices and noise robust speech-recognition systems. Using stochastic computation, a power-and-area hungry multiplier used in a digital filter is replaced by a simple logic gate, leading to area-efficient hardware. However, a straightforward implementation of the stochastic gammatone filter suffers from significantly low accuracy in computation, which results in a low dynamic range (a ratio of the maximum to minimum magnitude) due to a small value of a filter gain. To improve the computation accuracy, gain-balancing techniques are presented that represent the original gain as the product of multiple larger gains introduced at the second-order sections. In addition, dynamic scaling techniques are proposed that scales up small values only on stochastic domain in order to reduce the number of stochastic bits required while maintaining the computation accuracy. For performance comparisons, the proposed stochastic gammatone filters are designed and evaluated on taiwan semiconductor manufacturing company (TSMC) 65-nm CMOS technology. As a result, the proposed filter achieves an area reduction of 90.7% and an energy reduction of 91.8% in comparison with a fixed-point gammatone filter at the same sampling frequency and a comparable dynamic range.