Fits~ Overview –Overlay

Model Type（模型类型）：列表框显示了FIR Fit Plots子选项卡上选择的当前模型类型。
Model Parameters and Limits/Confidence（模型参数和限制/置信度）：显示的参数量取决于设置的模型类型。在每个单元格中显示了参数值和上下限（或置信区间）。与该输入—输出组相对应的拟合统计在每个单元格表的底行显示。
此窗口提供的一些其他选项：
Parameter Constraints（参数约束）：通过适当地更改上下限值，对参数设置约束。你可以将模型参数Freeze（冻结）为当前值，并使用右键单击菜单选项将模型的所有参数冻结为当前值。你还可以冻结给定单元格中的所有参数。冻结参数将以淡蓝色背景颜色突出显示。
你可以使用Unfreeze（解冻）和Unfreeze all（解冻所有）同时取消冻结参数或所有约束参数。包含有冻结模型限制的单元格变灰。你还可以选择使用FIR Fit的结果重新初始化单元格中的所有模型参数。右键单击选项Freeze Model（冻结模型），Unfreeze Model（解冻模型），Unfreeze all（解冻所有）和Reinitialize Model From FIR Fit（从FIR中重新初始化模型）仅在PAR Fit设置模式中可用。在拟合PAR模型后，只有右键菜单选项中的Freeze Parameter（冻结参数）可用。再次单击FIR Fit将重新激活其他右键单击选项。

Overlay（层叠）
比较FIR fit的阶跃响应，从模型简化得到的参数模型，以及Overlay（层叠）窗口上辨识的参数模型。
Overlay（层叠）窗口由阶跃响应曲线矩阵组成，在图表下方有一个图例表。单击单元格可获得与该单元格中的输入—输出关系对应的拟合统计数据和整体输出拟合统计。增益参数也显示在此表中。

层叠窗口字段
Scaling（缩放）：包括 Unit（单位）和 Normalized（归一化）缩放选项。
使用 Unit（单位）缩放时，每个模型阶跃响应对应于输入中的单位阶跃变化，并且每个单元被缩放以独立地跨越所绘制阶跃响应的整个范围。
使用 Normalized（归一化）缩放时，每个模型阶跃响应对应于正常变化的阶跃变化值。同一列中的所有单元格具有相同的比例，并且它将根据列上最大正负增益按比例进行缩放。

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**Model Type: **The list box displays the current type of model selected on the FIR Fit Plots subtab.
Model Parameters and Limits/Confidence: The number of parameters displayed depends on the set model type. Parameter values and the high and low limits (or confidence bounds) are shown in each cell. The Fit Stat corresponding to that input-output pair is shown in the bottom row of each cell table.
Some of the other options available in this window:
**Parameter Constraints: **Place constraints on parameters by changing the appropriate low and high values. You can Freeze a model parameter to its current value and also freeze all the parameters of a model to their current values by using the right-click menu options. You can also freeze all parameters within a given cell. Frozen parameters will be highlighted by light blue background color.
You can unfreeze parameters or all constrained parameters at the same time using Unfreeze and Unfreeze all. The cells containing limits of a frozen model are grayed out. You can also choose to reinitialize all the model parameters in the cell with results from the FIR Fit. Right click options Freeze Model, Unfreeze Model, Unfreeze all, and Reinitialize Model From FIR Fit are only available in the PAR Fit setup mode. After fitting PAR Model, only right click menu option Freeze Parameter is available. Clicking on FIR Fit again will reactivate the other right click options.
Overlay
Compare the step responses of the FIR fit, the parametric model resulting from a model reduction, and the identified parametric model on the Overlay window.
The Overlay window consists of a matrix of step response plots with a legend table below the plots. Click on a cell and obtain the Fit Stats corresponding to the input-output relationship in that cell and the overall output Fit Stat. The Gain parameter is also shown in this table.
Overlay Window Fields
Scaling：Options include Unit and Normalized scaling.
With **Unit scaling, each model step response corresponds to a unit step change in the input and each cell is scaled to span the entire range of the plotted step responses independently.
With Normalized **scaling, each model step response corresponds to a step change value of Normal change. All the cells in the same column have the same scale and it will scaled for the largest positive and negative gains over the column.

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2016.10.20