Dima, I have the CSA version of that scope and I have to admit this whole = discussion started after I made a side by side comparison between the = CSA8200 and the N5230A on channel measurements.=20 What do you think the possibility of an impulse response option on the = CSA8200? And yes, I agree that power distribution or anything deviated that much = from nominal 50 ohm impedance will be a different beast.=20 -----Original Message----- From: dmitry.a.smolyansky@xxxxxxxxxxxxxx [mailto:dmitry.a.smolyansky@xxxxxxxxxxxxxx] Sent: Tuesday, November 07, 2006 10:22 AM To: Chris Cheng Cc: si-list@xxxxxxxxxxxxx Subject: RE: [SI-LIST] Re: A question for the instrument guys on TDR and TDT BTW, it is not precisely "40/60 dB range." Look at the new Tektronix DSA8200 datasheet, it shows -70 dB at DC and decreases to -40 dB at 50 Ghz (http://www.tek.com/site/ps/85-17654/pdfs/85W_17654.pdf). Granted, an RF burst would provide a flatter dynamic range, but this is still pretty impressive for serial data S-parameter measurements (probably not for PDB characterization though). Thanks, =20 Dima Smolyansky Product Marketing Manager Tektronix, Inc. P.O. Box 500, MS 39-111 Beaverton, OR 97077-0001 503-627-7180 503-627-2260 (fax) -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Chris Cheng Sent: Monday, November 06, 2006 8:08 PM Cc: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: A question for the instrument guys on TDR and TDT I sure would like to see the VNA that can do real system channel =3D measurements at 100db after fixture and cabling. On the other hand, even at 40/60db range, a sampling scope may be good = =3D enough for a channel measurement up to a few GHz. Not a bad alternative. -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Istvan Novak Sent: Monday, November 06, 2006 7:50 PM To: Chris Cheng Cc: istvan.novak@xxxxxxx; si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: A question for the instrument guys on TDR and TDT The 'why not' is an interesting question, and you may get several=3D20 different answers, dependent on priorities. My answer is that a scope is OK for low=3D20 dynamic range or low-frequency measurements, in those applications it is cheaper than=3D20 VNA and works fine. On the other hand, VNAs can achieve 100+ dB dynamic range=3D20 easily; to get that in a scope, the effective number of bits would need to = be=3D20 16+, not available today on fast scopes.=3D20 If milliohms need to be measured, VNA is hard to beat. For tens and hundreds of milliohms or higher, scope would be acceptable. Regards, Istvan Chris Cheng wrote: >I would agree. However, the question is not whether the scope is =3D capable =3D3D >of doing it but why not ? The controls are almost there (for the =3D3D >TDR/TDT) and de-embedding is a simple step of shifting the reference = =3D =3D3D >plane or simple post processing FIR filter (something advance sampling =3D =3D3D >scope can already do). A $40K+ VNA vs. a free firmware upgrade on the = =3D =3D3D >sample scope. Which one will you choose !? > >-----Original Message----- >From: Istvan Novak [mailto:istvan.novak@xxxxxxxxxxx] >Sent: Monday, November 06, 2006 5:31 PM >To: Chris Cheng >Cc: si-list@xxxxxxxxxxxxx >Subject: Re: [SI-LIST] A question for the instrument guys on TDR and = =3D TDT > > >Chris, > >The answer is yes (as long as the network is 'sufficiently' linear). = =3D =3D3D20 >The finite rise time >shows up as filtering, what happens in all simulations or =3D measurements=3D3D20 >anyway, >even if we neglect the effect of risetime. If you need the impedance = =3D of =3D3D > >a power >distribution network, the quantization of the receiving instrument =3D will=3D3D20 >set the noise floor. > >Regards, > >Istvan Novak >SUN Microsystems > >Chris Cheng wrote: > > =3D20 > >>I can understand the merit of a step response and direct read out of = =3D =3D3D >> =3D20 >> >=3D3D3D > =3D20 > >>impedance profile. >>Will it be easy to also include a mode with a sharp pulse instead of = =3D =3D3D >> =3D20 >> >=3D3D3D > =3D20 > >>step for an impulse response ? If you have a circuit to generate a =3D 35ps =3D3D >> =3D20 >> >=3D3D3D > =3D20 > >>step, can you use it to generate a 35ps pulse also ? I think there are =3D =3D3D >> =3D20 >> >=3D3D3D > =3D20 > >>steps you can do to convert one to the other but a direct impulse =3D =3D3D3D >>response is just too good to pass up. >>Network analyzer on the cheap. >>Thanks in advanced, >>Chris >> >> >>=3D3D20 >> >> =3D20 >> > > =3D20 > ------------------------------------------------------------------ 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 FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: =3D20 //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 =3D20 ------------------------------------------------------------------ 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 FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: =20 //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 =20 ------------------------------------------------------------------ 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 FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ 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