TDR Analysis of Board Level Crosstalk

Location: $HPEESOF_DIR/examples/RF_Board/TDRcrosstalk_prj

Objective

This project shows several time-domain step and pulse response simulations. These simulations illustrate how signals are coupled from one transmission line to another, as well as how much a pulse waveform is degraded due to impedance mismatches. These set-ups also model time-domain reflectometry (TDR).

Setup

1. "LinearStepResp_Simple" is just a simulation of two transmission lines of different impedances, which cause reflections and distortion in the transmitted waveform.
2. "LinearStepResp_test" does a swept-frequency simulation to model the step response of an 8-coupled transmission line structure with two bends and different impedances to generate mismatches. The frequency-domain data is converted to the time-domain in the data display, using the ts() function.
3. "LinearPulseResp_test" uses the LinearPulseResp instrument, which does a swept-frequency simulation to model the pulse response of the same transmission line structure.
4. "ConvStepResp_test" does the same simulation as LinearStep_Resp_test, except that it uses the Transient simulator, which will use convolution if distributed elements are included on the schematic.
5. "ConvPulseResp_test" does the same simulation as LinearPulseResp_test, except that it uses the Transient simulator, which will use convolution if distributed elements are included on the schematic.
   

Analysis

Figure 1: Result from a transient analysis of an 8-coupled transmission line structure.