kudjung
Member level 4
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Dear All,
I just wonder whether we can have any method that roughly measure PCB impedance value or look at impedance discontinuty if we only have a high speed oscilloscope but not the TDR.
I use to try emulating the TDR using a 25 MHz signal generator and a scope but that work for a very long cable.
As i understand we will need a very short pulse to look at PCB impedance.
I just read through some of the very fast pulse generation method and found some topic about SRD(step recovery diode) which can generate pulse in ps range.
Anyone has any experience with this SRD or any thinking whether this method will work in trying to look at impedance discontinuty or measuring PCB impedance value. If we just generate the pulse using SRD and then look at reflected signal using a high speed oscilloscope.
Thanks for any suggestion.
Kudjung
I just wonder whether we can have any method that roughly measure PCB impedance value or look at impedance discontinuty if we only have a high speed oscilloscope but not the TDR.
I use to try emulating the TDR using a 25 MHz signal generator and a scope but that work for a very long cable.
As i understand we will need a very short pulse to look at PCB impedance.
I just read through some of the very fast pulse generation method and found some topic about SRD(step recovery diode) which can generate pulse in ps range.
Anyone has any experience with this SRD or any thinking whether this method will work in trying to look at impedance discontinuty or measuring PCB impedance value. If we just generate the pulse using SRD and then look at reflected signal using a high speed oscilloscope.
Thanks for any suggestion.
Kudjung