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https://designers-guide.org/forum/YaBB.pl Measurements >> RF Measurements >> Frequency Response using a TDR https://designers-guide.org/forum/YaBB.pl?num=1264206695 Message started by Nicole Mun on Jan 22nd, 2010, 4:31pm |
Title: Frequency Response using a TDR Post by Nicole Mun on Jan 22nd, 2010, 4:31pm Hi folks, I need to measure VSWR and insertion loss at 500Mhz. But I dont have signal generator and power meter. Yet i can get a cable testing TDR with adjustable pulse. Would it be possible to measure insertion loss by adjusting pulse so that it has fundamental frequency near 500Mhz. Thanks for your advice.... |
Title: Re: Frequency Response using a TDR Post by pancho_hideboo on Jan 22nd, 2010, 7:13pm Nicole Mun wrote on Jan 22nd, 2010, 4:31pm:
VSWR is equivalent to |S11|. Insertion Loss is |S21|2. Nicole Mun wrote on Jan 22nd, 2010, 4:31pm:
If you have oscilloscope having TDR function, you can measure VSWR by TDR. Insertion Loss can be measured by TDT. Even if your oscilloscope doesn't have TDR function, you can do TDR by using pulse generator and power divider with oscilloscope. http://en.wikipedia.org/wiki/Time-domain_reflectometer http://en.wikipedia.org/wiki/Time-domain_reflectometry What instruments do you have ? Show me list of all instruments you have. |
Title: Re: Frequency Response using a TDR Post by Nicole Mun on Jan 27th, 2010, 9:09am pancho_hideboo, thanks for your response. I am sorry I did not realize i posted in the wrong area and it was removed to RF measurements appropriately Regarding "What do you mean by "adusting pulse" ?" I have a cable testing TDR riser bond 1205cx http://www.radiodetection.com/servedoc.asp?filename=1205cxaManual.pdf It allows to adjust pulse width and shows dBrL So I was wondering the following.... Since it will be sending a series of pulses, instead of a single pulse. and pulse width is adjustable, I may be able to create something closer to 500Mhz. then would i be able to approximate vswr and insertion loss with a tdr. again thanks for the response. |
Title: Re: Frequency Response using a TDR Post by pancho_hideboo on Feb 4th, 2010, 3:43am Nicole Mun wrote on Jan 27th, 2010, 9:09am:
Nicole Mun wrote on Jan 27th, 2010, 9:09am:
Nicole Mun wrote on Jan 27th, 2010, 9:09am:
Do you understand TDR correctly ? Generally you can not measure frequency characteristics of impedance by TDR. If you want to consider frequency characteristics in TDR, rather control rise time of pulse not period of pulse. Nicole Mun wrote on Jan 27th, 2010, 9:09am:
Again do you understand TDR correctly ? |
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