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Design+                                                        Approximate signed multipliers design approach




            Table 1. Circuit‑level simulations results
            Multipliers                          Power (µW)         Delay (ps)       PDP (fj)         Transistor
            Exact Arasteh et al. 31              20.6               291              6.01             1,585
            Proposed in Ahmadinejad et al. 34    7.6                252              1.92             1,232
            Proposed in Sabetzadeh et al. 40     8.7                215              1.88             1,132
            Proposed in Ahmadinejad and Moaiyeri 41  9.5            216              2.07             1,210
            Proposed in Pei et al. 42            16.8               293              4.9              1,728
            Proposed in Kumar et al. 43          15.9               228              3.64             1,680
            Proposed in Esposito et al. 44       11.8               272              3.21             1,564
            Proposed in Waris et al. 45          16                 273              4.38             1,574
            Proposed in Strollo et al. 46        18.1               322              5.85             2,072
            Proposed in Fang et al. 47           14.9               289              4.32             1,820
            Proposed in Baraati et al. 48        10.2               215              2.2              1,216
            PASM
             Ignoring carries                    7.8                191              1.48             1,122
             Using Ha and Lee 33                 5.6                152              0.85             1,028
             Using Ahmadinejad et al. 34         6.9                148              1.02             1,098
             Using Yang et al. 35                7.1                148              1.5              1,060
            Abbreviation: PASM: Performance-optimized approximate signed multiplier.

            Table 2. Accuracy analysis results of the proposed multipliers

            Multipliers                        NMED (×10 )       MRED (×10 )       IPA‑MRED (×10 )      NoEB
                                                       ‑4
                                                                         ‑2
                                                                                              ‑4
            Proposed in Ahmadinejad et al. 34  18                0.8               1.6                  6.1
            Proposed in Sabetzadeh et al. 40   17                3.5               3.1                  9
            Proposed in Ahmadinejad and Moaiyeri 41  40          4.4               4.1                  6.2
            Proposed in Pei et al. 42          7.2               1.8               0.9                  10
            Proposed in Kumar et al. 43        4.2               0.7               1.2                  10.4
            Proposed in Esposito et al. 44     120               4.8               5.2                  5.1
            Proposed in Waris et al. 45        52                7.5               8.4                  7.2
            Proposed in Strollo et al. 46      4                 2.2               1.1                  6.9
            Proposed in Fang et al. 47         6                 0.4               0.9                  6.1
            Proposed in Baraati et al. 48      57                1.5               2.4                  8.1
            PASM
             Ignoring carries                  43                5.3               0.8                  7.9
             Using Ha and Lee 33               45                5.7               0.6                  7.8
             Using Ahmadinejad et al. 34       17                2.3               0.4                  9.9
             Using Yang et al. 35              22                4.1               0.5                  8.1
            Abbreviations: IPA-MRED: Input probability-aware mean relative error distance; MRED: Mean relative error distance; NMED: Normalized mean error
            distance; NoEB: Number of effective bits; PASM: Performance-optimized approximate signed multiplier.

            (MSSIM).  The results of this assessment, including the   4.4. NN applications
                    39
            average PSNR and MSSIM values for the image sharpening   This section examines the effectiveness of the proposed
            application, are presented in  Table 3. As shown, the   multiplier in NN applications, specifically through the
            approximate multiplier designed using the proposed   implementation of a multilayer perceptron (MLP) for
            approach outperforms previously developed approximate   the MNIST dataset and GNet for the SVHN dataset. The
            multipliers.                                       MLP consists of 784 inputs (representing image pixels),


            Volume 1 Issue 1 (2024)                         5                                doi: 10.36922/dp.3882
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