Equations for twisted-pair (was Re: Zo)
** Virus Warning Message (on gemini2.ieee.org) Found virus TROJ_NAVIDAD.E in file Emanuel.exe The file is deleted. If you have questions, contact virus-ad...@ieee.org * Hi! Robert: I'm very interested in the emperical equations that you have for twisted-pair. Do you mind sharing this with me ? Thanks in advance Perry Qu Robert Macy wrote: Did you find out what you need? Somewhere around here I have the equations that closely approximate twisted pair for 26 Awg and 28 Awg wire from DC to 10MHz. They were derived from empirical modeling. You can make various approximations to simplify their use. That includes impedance, loss per length vs frequency, etc. I don't think they take into account being close to conductors, like a shield, or crosstalk between pairs, because that's another analysis, but they're *extremely* useful for predicting attenuation versus frequency for analyzing the expected performance one will get from DSL modems. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: William D'Orazio dora...@cae.ca To: EMC Posting (E-mail) emc-p...@majordomo.ieee.org Date: Thursday, January 11, 2001 7:20 AM Subject: Zo Does anybody know the characteristic impedance of a twisted pair? Thanks in advance, ...OLE_Obj... William D'Orazio CAE Electronics Ltd. Electrical System Designer Phone: (514) 341-2000 (X4555) Fax: (514)340-5552 Email: dora...@cae.ca ** Virus Warning Message (on gemini2.ieee.org) Emanuel.exe is removed from here because it contains a virus. *
Equations for twisted-pair (was Re: Zo)
** Virus Warning Message (on gemini2.ieee.org) Found virus TROJ_NAVIDAD.E in file Emanuel.exe The file is deleted. If you have questions, contact virus-ad...@ieee.org * Hi! Robert: I'm very interested in the emperical equations that you have for twisted-pair. Do you mind sharing this with me ? Thanks in advance Perry Qu Robert Macy wrote: Did you find out what you need? Somewhere around here I have the equations that closely approximate twisted pair for 26 Awg and 28 Awg wire from DC to 10MHz. They were derived from empirical modeling. You can make various approximations to simplify their use. That includes impedance, loss per length vs frequency, etc. I don't think they take into account being close to conductors, like a shield, or crosstalk between pairs, because that's another analysis, but they're *extremely* useful for predicting attenuation versus frequency for analyzing the expected performance one will get from DSL modems. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: William D'Orazio dora...@cae.ca To: EMC Posting (E-mail) emc-p...@majordomo.ieee.org Date: Thursday, January 11, 2001 7:20 AM Subject: Zo Does anybody know the characteristic impedance of a twisted pair? Thanks in advance, ...OLE_Obj... William D'Orazio CAE Electronics Ltd. Electrical System Designer Phone: (514) 341-2000 (X4555) Fax: (514)340-5552 Email: dora...@cae.ca ** Virus Warning Message (on gemini2.ieee.org) Emanuel.exe is removed from here because it contains a virus. *
Re: Zo
Did you find out what you need? Somewhere around here I have the equations that closely approximate twisted pair for 26 Awg and 28 Awg wire from DC to 10MHz. They were derived from empirical modeling. You can make various approximations to simplify their use. That includes impedance, loss per length vs frequency, etc. I don't think they take into account being close to conductors, like a shield, or crosstalk between pairs, because that's another analysis, but they're *extremely* useful for predicting attenuation versus frequency for analyzing the expected performance one will get from DSL modems. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: William D'Orazio dora...@cae.ca To: EMC Posting (E-mail) emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, January 11, 2001 7:20 AM Subject: Zo Does anybody know the characteristic impedance of a twisted pair? Thanks in advance, ...OLE_Obj... William D'Orazio CAE Electronics Ltd. Electrical System Designer Phone: (514) 341-2000 (X4555) Fax: (514)340-5552 Email: dora...@cae.ca --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Zo
E1 cable, which is 26 AWG, is 120 0hms and T1 is 100 ohms. Impedance will vary depending on things such as; shielding, wire gauge, twists/ft, etc. Bill Fleury -Original Message- From: William D'Orazio [mailto:dora...@cae.ca] Sent: Thursday, January 11, 2001 8:49 AM To: EMC Posting (E-mail) Subject: Zo Does anybody know the characteristic impedance of a twisted pair? Thanks in advance, ...OLE_Obj... William D'Orazio CAE Electronics Ltd. Electrical System Designer Phone: (514) 341-2000 (X4555) Fax: (514)340-5552 Email: dora...@cae.ca --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Zo
If you don't have a network analyzer, you can a good handle on the impedance using a signal generator, scope and a resistor. Make sure the electrical length of the cable is much larger (10X) than the rise time of the generator. Load one end with 100 ohms or so and connect the generator and scope at the other end. If the impedance is more or less than the resistor value, you will see reflections from the resistor. Change the resistor value until the reflections are minimized and that is the impedance. Richard Woods -- From: David Spencer [SMTP:dspen...@oresis.com] Sent: Thursday, January 11, 2001 12:42 PM To: 'William D'Orazio'; EMC Posting (E-mail) Subject: RE: Zo Hi William, This is a dynamic quantity dependent on the size of the wire, number of twists, and frequency range of interest. You can get a lot of good information from the web pages of various twisted pair cable manufacturers. The normal impedance for twisted pair sold as CAT 3 and CAT 5 (and others) is 100 ohms for a given frequency range, 1-16 MHz for CAT3 and 1-100MHz for CAT5. There are others available (E1 telephony @ 120 ohms.) New flavors of twisted pair are extending the frequency range up to 350MHz. If you have access to a network analyzer, you can probably characterize a given twist/inch of xxASG wire for your frequency range of interest. Hope this helps, Dave Spencer Oresis Communications -Original Message- From: William D'Orazio [mailto:dora...@cae.ca] Sent: Thursday, January 11, 2001 6:49 AM To: EMC Posting (E-mail) Subject: Zo Does anybody know the characteristic impedance of a twisted pair? Thanks in advance, ...OLE_Obj... William D'Orazio CAE Electronics Ltd. Electrical System Designer Phone: (514) 341-2000 (X4555) Fax: (514)340-5552 Email: dora...@cae.ca --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Zo
Hi William, This is a dynamic quantity dependent on the size of the wire, number of twists, and frequency range of interest. You can get a lot of good information from the web pages of various twisted pair cable manufacturers. The normal impedance for twisted pair sold as CAT 3 and CAT 5 (and others) is 100 ohms for a given frequency range, 1-16 MHz for CAT3 and 1-100MHz for CAT5. There are others available (E1 telephony @ 120 ohms.) New flavors of twisted pair are extending the frequency range up to 350MHz. If you have access to a network analyzer, you can probably characterize a given twist/inch of xxASG wire for your frequency range of interest. Hope this helps, Dave Spencer Oresis Communications -Original Message- From: William D'Orazio [mailto:dora...@cae.ca] Sent: Thursday, January 11, 2001 6:49 AM To: EMC Posting (E-mail) Subject: Zo Does anybody know the characteristic impedance of a twisted pair? Thanks in advance, ...OLE_Obj... William D'Orazio CAE Electronics Ltd. Electrical System Designer Phone: (514) 341-2000 (X4555) Fax: (514)340-5552 Email: dora...@cae.ca --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Zo
Zo= eta(free space)/ (pi * sqrt(epsilon effective) * inversecosh (D/d) where epsilon effective is = 1 + (.25 + 0.0004 theta^2)*(epsilon of insulation-1.) use 0.001 instead of 0.0004 for soft insulation theta= inversetan( twists per length * pi * D) D= diameter of coductor + insulator d = diameter of conductor I am attaching a Powerpoint file that should help twistedpairzo.ppt Vicente RodrÃguez, Ph.D., E.I.T. RF/Electromagnetics Engineer ETS-Lindgren (an ESCO Company) P.O.Box 80589, Austin TX 78708-0589 phone 512.835.4684 x648 fax 512.835.4729 vicente.rodrig...@emctest.com http://www.emctest.com http://home.austintx.com/~vicenter -Original Message- From: William D'Orazio [SMTP:dora...@cae.ca] Sent: Thursday, January 11, 2001 8:49 AM To: EMC Posting (E-mail) Subject: Zo Does anybody know the characteristic impedance of a twisted pair? Thanks in advance, ...OLE_Obj... William D'Orazio CAE Electronics Ltd. Electrical System Designer Phone: (514) 341-2000 (X4555) Fax: (514)340-5552 Email: dora...@cae.ca --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org twistedpairzo.ppt Description: MS-Powerpoint presentation
Re: Zo
The old style B insulated wire used for telephone drops and similar lamp cord when twisted always made good balanced feedline for antennas with an impedance somewhere around 70 ohms. This assumes conductors in the range 16-18ga. a.w.g. with rubber insulation. Ralph Cameron EMC Consulting and Suppression of Consumer Electronic Equipment (After sale) - Original Message - From: William D'Orazio dora...@cae.ca To: EMC Posting (E-mail) emc-p...@majordomo.ieee.org Sent: Thursday, January 11, 2001 9:49 AM Subject: Zo Does anybody know the characteristic impedance of a twisted pair? Thanks in advance, ...OLE_Obj... William D'Orazio CAE Electronics Ltd. Electrical System Designer Phone: (514) 341-2000 (X4555) Fax: (514)340-5552 Email: dora...@cae.ca --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Zo
William, If you want to calculate the impedance, the equation for a lossless line is simply Z = sqrt(l/c) where l = per unit length inductance c = per unit length capacitance. For lossy line, it gets more complex: Z = sqrt((r+jwl)/(g+jwc)) where unit length parameters are r = resistance (series, as a function of frequency) w = radian frequency g = conductance (line to line) DB -- From: wo...@sensormatic.com[SMTP:wo...@sensormatic.com] Reply To: wo...@sensormatic.com Sent: Thursday, January 11, 2001 8:25 AM To: emc-p...@majordomo.ieee.org Subject: RE: Zo My experience is that it is in the order of 75-150 ohms and depends upon the material, lay and shielding, if any. Increased lay and shielding will reduce the impedance. Richard Woods -- From: William D'Orazio [SMTP:dora...@cae.ca] Sent: Thursday, January 11, 2001 9:49 AM To: EMC Posting (E-mail) Subject: Zo Does anybody know the characteristic impedance of a twisted pair? Thanks in advance, ...OLE_Obj... William D'Orazio CAE Electronics Ltd. Electrical System Designer Phone: (514) 341-2000 (X4555) Fax: (514)340-5552 Email: dora...@cae.ca --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Zo
My experience is that it is in the order of 75-150 ohms and depends upon the material, lay and shielding, if any. Increased lay and shielding will reduce the impedance. Richard Woods -- From: William D'Orazio [SMTP:dora...@cae.ca] Sent: Thursday, January 11, 2001 9:49 AM To: EMC Posting (E-mail) Subject: Zo Does anybody know the characteristic impedance of a twisted pair? Thanks in advance, ...OLE_Obj... William D'Orazio CAE Electronics Ltd. Electrical System Designer Phone: (514) 341-2000 (X4555) Fax: (514)340-5552 Email: dora...@cae.ca --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
