按窗函数缩放
- 更新时间2025-07-30
- 阅读时长5分钟
在时域信号上和输出窗常量上使用缩放窗，用于后续分析。通过连线数据至信号输入输入端可确定要使用的多态实例，也可手动选择实例。
对加窗时域信号进行缩放，计算加窗波形的功率或幅值时，所有窗都能提供窗精度限制之内的电平。该VI也可返回所选窗的重要窗常量。使用计算功率谱的VI（例如，功率及频率估计VI）时，需用下列常量。
定义等式
所有不带缩放的余弦窗，其定义如下列等式所示。
，n是X中元素的数量，m是窗系数数组a[]中元素的数量。
对于该VI，上述等式除以相干增益(cg)，得到如下等式。
各类型窗的系数和窗参数
以下列出了针对不同类型的窗可在该VI中使用的a系数和窗参数。每种类型的窗都有下列窗参数：
- 相干增益(cg)
- 等效噪声带宽(enbw)
- 6dB带宽(6dB BW)
| 矩形 | |
|---|---|
| a[]为空，因为没有加任何窗。 | cg = 1 |
| 窗方程为yi = xi | enbw = 1 |
| 6dB BW = 1.21 | |
| Hanning | |
| a0 = 0.5 | cg = 0.5 |
| a1 = 0.5 | enbw = 1.5 |
| 6dB BW = 2.0 | |
| Blackman-Harris | |
| a0 = 0.42323 | cg = 0.42323 |
| a1 = 0.49755 | enbw = 1.708538 |
| a2 = 0.07922 | 6dB BW = 2.27 |
| Exact Blackman | |
| a0 = 0.42659071367153911200 | cg = 0.42659071367 |
| a1 = 0.49656061908856408100 | enbw = 1.693699 |
| a2 = 0.07684866723989682010 | 6dB BW = 2.25 |
| Blackman | |
| a0 = 0.42 | cg = 0.42 |
| a1 = 0.5 | enbw = 1.726757 |
| a2 = 0.08 | 6dB BW = 2.3 |
| Flat Top | |
| a0 = 0.215578948 | cg = 0.215578948 |
| a1 = 0.41663158 | enbw = 3.770246506303 |
| a2 = 0.277263158 | 6dB BW = 4.58 |
| a3 = 0.083578947 | |
| a4 = 0.006947368 | |
| 4阶Blackman-Harris | |
| a0 = 0.35875 | cg = 0.35875 |
| a1 = 0.48829 | enbw = 2.004353 |
| a2 = 0.14128 | 6dB BW = 2.67 |
| a3 = 0.01168 | |
| 7阶Blackman-Harris | |
| a0 = 0.27105140069342415 | cg = 0.27105140069342415 |
| a1 = 0.43329793923448606 | enbw = 2.631905 |
| a2 = 0.21812299954311062 | 6dB BW = 3.5 |
| a3 = 0.065925446388030898 | |
| a4 = 0.010811742098372268 | |
| a5 = 7.7658482522509342E-4 | |
| a6 = 1.3887217350903198E-5 | |
| Low Sidelobe | |
| a0 = 0.323215218 | cg = 0.323215218 |
| a1 = 0.471492057 | enbw = 2.215350782519 |
| a2 = 0.17553428 | 6dB BW = 2.95 |
| a3 = 0.028497078 | |
| a4 = 0.001261367 | |