Viterbi algorithm (VA) on time frequency (TF) distribution is a highly performed instantaneous frequency (IF) estimator. However, inaccurate IFs may be tracked due to switch problem in VA when signal components are overlapped on the TF plane. In order to address the problem, this paper first assumes the IF linearity in the overlapped TF regions should not change much, then, a new penalty function describing the variation of IF linearity based on the linear least square fitting technique is developed, and finally, a novel algorithm composed of two IF estimates is introduced. In the first coarse IF estimation, original VA is applied to determine the TF overlapped regions. In the second fine IF estimation, a modified VA employing the new penalty function is applied in the overlapped regions, while the original VA still functions in the non-overlapped regions. Simulations indicate the proposed algorithm can effectively suppress the switch problem and thus can achieve accuracy improvement especially for non-monotonous IF curves compared to other VA-based estimators.

中文翻译：

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基于维特比算法的重叠多分量信号中频估计

时频 (TF) 分布上的维特比算法 (VA) 是一种高性能的瞬时频率 (IF) 估计器。然而，当信号分量在 TF 平面上重叠时，由于 VA 中的开关问题，可能会跟踪不准确的 IF。为了解决这个问题，本文首先假设重叠TF区域中的中频线性度变化不大，然后，基于线性最小二乘拟合技术开发了描述中频线性度变化的新惩罚函数，最后，介绍了一种由两个 IF 估计组成的新算法。在第一次粗略的 IF 估计中，应用原始 VA 来确定 TF 重叠区域。在第二个精细 IF 估计中，在重叠区域中应用了采用新惩罚函数的修改后的 VA，而原始 VA 仍然在非重叠区域中起作用。仿真表明，与其他基于 VA 的估计器相比，所提出的算法可以有效地抑制开关问题，因此可以实现精度提高，尤其是对于非单调 IF 曲线。