nonstationary filter的用法和样例：
例句
- A reassignment method for nonstationary time-frequency joint analysis is introduced.
介绍了非平稳信号时频联合分析中的重排方法。 - Based on the features of existing structure, the nonstationary random process model of resistance for existing structure is proposed.
根据服役结构的特点，提出了服役结构抗力的非平稳随机过程模型。
