### sparameter to TDR

Hi ,Can any one please suggest how do I convert my sparameter data to TDRI have a sparameter file generated for a diff pair using Hyperlynx.is it possible to get the TDR matrix with Hyperlynx .ThanksRoopesh

roopesh.badala
6 years 10 months 22 days

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Answered byorphanou
6 years 10 months 21 days

A typical 20Ghz measurement with some intuitive interpolation schemes will be a good enough resolution for a good TDR. The main issue is how passive your s-parameter data is and that you might have less and more difficult control of adjusting. If your channel is not too long though you might get away with it..... -----

Answered bygoswamisurjendra
6 years 10 months 21 days

Hi Roopesh,Although Pat and Gert have answered the question already I would like toadd my two pence.While converting the s-parameter data to TDR, the s-parameter max frequencyand the frequency resolution decides the TDR output quality.In case your TDR data max frequency is not high enough then the time domainTDR data may not be what you desire.The situation is analogous to a situation in which you have a TDR data witha pulse having a higher rise time and consequently harmonics at higherfrequency have lower amplitude. Such a input waveform would give us a TDRplot with a lower discontinuity resolution.To decide on the max frequency required in the s-param file for the desiredaccuracy we have the rise time to max frequency equation known to all.RegardsSurjendraOn Thu, Mar 6, 2014 at 6:12 PM, Roopesh Badalawrote:> Hi ,> Can any one please suggest how do I convert my sparameter data to TDR>> I have a sparameter file generated for a diff pair using Hyperlynx.>> is it possible to get the TDR matrix with Hyperlynx .>>> Thanks>> Roopesh>>>

Answered byal
6 years 10 months 21 days

Our DesignCon2014 paper co-authored with Anritsu addresses the sampling, interpolation, and S-parameter work flow issues for improving time domain transforms from S-parameters.A copy of the paper is on our website in papers section, ?Managing S-parameters for 10-32Gbpsec Time-Domain Simulation?The focus of the paper is to establish the correct harmonic sampling interval, use Fstart consistent with measurement length, validate calibration, and then pass the measurement through a workflow that tests for passivity/causality and other properties related to the DUT structure, such as reciprocity and symmetry. The workflow and a rational compact model representation is being done with Simbeor.- AlProducts for the Signal Integrity PractitionerAlfred P. NevesChief TechnologistOffice: 503-679-2429www.wildrivertech.comOn Mar 7, 2014, at 11:24 AM, Antonis Orphanouwrote:> > A typical 20Ghz measurement with some intuitive interpolation schemes will be > a good enough resolution for a good TDR. The main issue is how passive your > s-parameter data is and that you might have less and more difficult control > of adjusting. If your channel is not too long though you might get away with > it..... > > > > -----

Answered byorphanou
6 years 10 months 22 days

I like the old-school way to convert s-parameter data to TDR (although more laborious..!) (1). Solve for Z_input as a function of the input reflection coefficient s11(2). Multiply in frequency domain with a step pulse (3). Do an iFFTMatlab is ideal for that type of scriptingPossible issues with step response impedance: passivity of your s-parameter matrix-----

Answered byPatrick_Carrier
6 years 10 months 22 days

You can also view the TDR impedance plot of an S-parameter directly in the Touchstone Viewer in HyperLynx.--Pat-----

Answered byGert.Havermann
6 years 10 months 22 days

Isn't Hyperlynx capable of doing time domain simulation? Just take a voltage Step source, add a resistor for internal Resistance, apply it to the S-Parameters and look at the reflections.BRGert