### Where To Find This Example

#### AWR Version 13

#### AWR Version 12

### Design Notes

**Filter s21 vs f-fo script.emp**

Whereas Microwave Office plots frequency f as the x-axis, in some applications, like filters, it may be required to plot a response as a function of f/fo on the x-axis. This project plots S21 as a function of normalized frequency f/fo by using output equations for a simple behavioral filter.

**Overview**

In order to plot S21 with a modified x-axis of f/fo, this project calculates f/fo x-axis points with output equations. Output equation pulls out the S21 data from the graph, pulls the simulation frequencies using the swpvals variable, sets fo=7GHz, and calculates f/fo. The graph "S21 vs norm f" uses an output equation to plot the S21 against the new x-axis.

**Output Equations**

The variable _FREQ makes the simulation frequency available as a variable withing Microwave Office. In the output equations _FREQ is divided by the chosen center frequency for the example, fo, in order to generate the normalized frequency "fnew" for the new x-axis. The S-parameter data is captured into a variable by the equation statement S21 = Schematic 1: DB(|S[2,1]|).

**Graph on New X-Axis**

The graph "S21 vs norm f" plots S21 on the "fnew" axis of f/fo. The measurement uses an output equation result