Hague David A, Buck John R
Sensors and Sonar Systems Department, Naval Undersea Warfare Center, Newport, Rhode Island 02840, USA.
Department of Electrical and Computer Engineering, University of Massachusetts Dartmouth, Dartmouth, Massachusetts 02747, USA.
J Acoust Soc Am. 2019 Jun;145(6):3741. doi: 10.1121/1.5113581.
This paper experimentally evaluates the Generalized Sinusoidal Frequency Modulated (GSFM) waveform, a generalization of the Sinusoidal Frequency Modulated (SFM) waveform. The Instantaneous Frequency (IF) of the GSFM resembles the time/voltage characteristic of a Linear Frequency Modulated (LFM) chirp waveform. Consequently, the GSFM possesses an Ambiguity Function (AF) that resembles a thumbtack shape. Practical sonar system design must consider two factors beyond the AF. The Spectral Efficiency (SE), defined as the ratio of energy in an operational frequency band to the total waveform energy, is another important metric for waveform design. The Peak-to-Average-Power Ratio (PAPR) quantifies how close the waveform is to constant amplitude. These measures predict a waveform's energy efficiency and ability to be accurately replicated on practical piezoelectric transducers, which have limits on both their bandwidth and maximum transmit power. This paper explores these design considerations for the GSFM waveform and evaluates its performance against a host of other well established waveforms using simulated and experimental acoustic data. The GSFM possesses superior SE, PAPR, and overall energy efficiency when compared to other thumbtack waveforms.
本文通过实验评估了广义正弦频率调制（GSFM）波形，它是正弦频率调制（SFM）波形的一种推广形式。GSFM的瞬时频率（IF）类似于线性频率调制（LFM）啁啾波形的时间/电压特性。因此，GSFM具有类似图钉形状的模糊函数（AF）。实际声纳系统设计必须考虑AF之外的两个因素。频谱效率（SE）定义为工作频带内的能量与总波形能量之比，是波形设计的另一个重要指标。峰均功率比（PAPR）量化了波形与恒定幅度的接近程度。这些指标预测了波形的能量效率以及在实际压电换能器上精确复制的能力，而实际压电换能器在带宽和最大发射功率方面都有局限性。本文探讨了GSFM波形的这些设计考量，并使用模拟和实验声学数据评估了它相对于许多其他成熟波形的性能。与其他图钉形波形相比，GSFM具有更高的SE、PAPR和整体能量效率。
