Touchstone File

A Touchstone file was originally a proprietary file format for the eponymous frequency-domain linear circuit simulator [ [http://www.microwaves101.com/encyclopedia/historyCAD.cfm#touchstone History of EEsof and Touchstone at Microwaves 101] ] from EEsof, launched in 1984. The simulator itself has long since been superseded [It was replaced by [http://eesof.tm.agilent.com/products/e8881a-new.html E8881 ADS Linear Simulator] ] , but its file format lives on. A Touchstone file (also known as an SnP file) is an ASCII text file used for documenting the n-port network parameter data and noise data of linear active devices, passive filters, passive devices, or interconnect networks. An example of the S-parameter section is here. Touchstone file format later became a de facto industry-standard file format not only for circuit simulators but also for measurement equipment (e.g. vector network analyzers, or VNAs), then later still an EIA standard (part of the [http://www.eda.org/ibis/ IBIS (I/O Buffer Information Specification)] project). Version 1.1 [ [http://www.eda.org/pub/ibis/connector/touchstone_spec11.pdf EIA IBIS Touchstone Spec 1.1] ] is current and an enhanced version (2.0) [ [http://www.vhdl.org/pub/ibis/adhoc/interconnect/ Folder with EIA IBIS Touchstone Spec 2 Drafts] ] is under review. Several enhancements to the file format, which allow additional description of the non-linearity of the component, have been proposed [ [http://eesof.tm.agilent.com/products/e8854a-new.html E8854A RF System Models] from Agilent EEsof EDA] under the P2D and S2D nomenclature.

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Trademark Notice

Touchstone is a registered trademark of Agilent Technologies, Inc.