Theory and Low-Power Design of Moving Accumulative Sign Filter

A novel down-sampling filter named moving accumulative sign filter (MASF) is proposed for low-power down-sampling of large-scale binary and ternary data. Besides, the MASF has greatly circuit realization advantages than state-of-the-art cascaded-integrator-comb (CIC) filter, especially in the area of low-power design. The theory of MASF is proposed and introduced comprehensively, including the algorithm model, transfer function, and frequency response characteristics. The pipeline voting architecture is applied to the implementation of the MASF to improve the speed of data processing, which simplifies the circuit structure and reduce the power consumption. The MASF circuits of general application based on pipeline voting are designed for binary and ternary signals only using D flip-flop and logic gates. The area and power consumption of MASF are reduced by 86% and 88% compared with CIC filter under the same conditions on FPGA. What's more, a hardware-friendly pooling algorithm named polar-pooling is proposed based on MASF for binary and ternary feature maps, which greatly reduces the time and space complexity of pooling. Compared with max-pooling and average-pooling, the processing time of polar-pooling is reduced by more than 75% for a $200\times 200$ binary image. The two-stage MASF circuit for ternary signal processing is implemented at 40-nm CMOS process, compared with state-of-the-arts cascade-of-integrators filter which cascading two integrators, the normalized power consumption of proposed two-stage MASF circuit has 67% reduction and the area has 75% reduction.