John, The equations on page 81 of High-Speed Digital System Design, by Stephen H. Hall, Garrett W. Hall, and James A. McCall (John Wiley & Sons, New York, 2000) match up with the equations on page 156 of Foundations for Microwave Engineering, Second Edition, by Robert E. Collin (Mc-Graw-Hill, New York, 1992). They do not appear in the first edition of Collin's book, which I also have in my library. Some electronics books give three or four variants of the same basic equation or parts/material properties in different chapters and appendices--which I find very confusing. So I write books and design documents bass-ackwards. After researching the basics of a topic, I'll write the appendices to document the equations, parts/materials properties, and other information that I expect to use throughout the document. Then I'll write the body of the document. Finally, I finish up by writing the introduction and preface. Thus, by using the reference material from the appendices, I can be sure of being consistent throughout the entire document... Or at least as consistent as one person can be in a project that consumes thousands of hours. My first book, Electronic System Design: Interference and Noise Control Techniques (now out of print), took me about 3,500 hours work spread out over 4 years. My second and third books, Robust Electronic Design Reference Book, Volumes 1 and 2 (coming out in late March, Kluwer Academic Publishers, http://www.wkap.nl/prod/b/1-4020-7739-4 ) consumed some 4,200 hours of my time in 2003 alone. John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu