### Where To Find This Example

#### AWR Version 13

#### AWR Version 12

This example is not available for AWR Version 12 or earlier.

### Design Notes

**Time and Frequency Domain Comparison**

This project demonstrates the ability to check how passive frequency domain models in a design will behave in the time domain.

**Overview**

Before simulating in the time domain it is often useful to check and see how the passive frequency domain models in a design will behave in the time domain. In AWRDE this comparison is very simple and involves duplicating the small signal frequency domain test bench and then using a special simulation option. **Note that this technique only works with passive frequency domain models and that the simulations must use the APLAC simulator**. The Linear > PASSIVE measurement can be used to confirm the passivity of the circuit. To compare active frequency domain models (e.g. s-parameters of a transistor) it is necessary to use time domain simulation and nonlinear measurements. Please contact AWR Support for additional detail.

**Filter Schematic**

Contains a passive filter design with MLIN models and an s-parameter file.

**Filter_TD Schematic**

Contains the same passive filter as the Filter Schematic but uses the Free Text=NETLIST_TD APLAC Simulation Option. The Free Text option is set by right clicking on the Filter_TD Schematic > Options > APLAC Sim. Click the Show Secondary button and scroll down to the Miscellaneous Options Category. The NETLIST_TD option causes models to be mapped to the time domain (even though the simulation is performed in the frequency domain).

**Passivity Graph**

Uses the PASSIVE Measurement to confirm that the Filter Schematic is passive.

**SParam Graph**

Compares S(2,1) and S(1,1) from the Filter Schematic (blue) and the time domain representation of the Filter Schematic (red).

**SModel Graph**

Uses the SModel Measurement to compare the Filter schematic to the time domain representation of the Filter Schematic. The -100 dB match is an almost perfect match. Read the SModel help doc for more details.