From: Daniel, Erik S. (Daniel.Erik@mayo.edu)
Date: Thu May 11 2000 - 05:14:34 PDT
> Second, yes thanks for giving me a chance to pick up on the
> subject of
> TDR. As you explain there are two primary methods one using
> two opposing pulses
> and the other using a single pulse to drive each line in turn and
> calculating the
> resultant differential impedance.
Can you provide more information on how exactly your instrument measures the
single-ended responses and subsequently computes the odd and even mode
impedances? Specifically, when you pulse line 1 and observe its response,
what is done with line 2? Is it grounded? Open? Terminated in 50 Ohms?
If it is terminated, is the voltage at this terminal sampled as well as the
voltage on line 1? What mathematics is then used to compute even and odd
impedances? It seems that with this type of measurement it is still
critical to ensure that identical pulse delay and pulse shape is used to
stimulate each of the lines independently -- what steps are taken to ensure
this is the case?
> There are advantages and disadvantages to both methods but we have
> done extensive testing on thousands of coupons and correlated
> results from
> both types of systems. We find the answers from both methods
> correlate well.
Could you post measurements to this list that illustrate this point?
Erik Daniel, Ph.D. Mayo Foundation
Voice: (507) 284-1634 Guggenheim 1011B
Fax: (507) 284-9171 200 First Street SW
E-mail: firstname.lastname@example.org Rochester, MN 55905
**** To unsubscribe from si-list or si-list-digest: send e-mail to
email@example.com. In the BODY of message put: UNSUBSCRIBE
si-list or UNSUBSCRIBE si-list-digest, for more help, put HELP.
si-list archives are accessible at http://www.qsl.net/wb6tpu
This archive was generated by hypermail 2b29 : Wed Nov 22 2000 - 10:50:17 PST