Joe Joseph Gray wrote: >> Did you use a resistive splitter or just a tee to split the signal? >> > > Just a tee. I have tees and terminators at each input of the 5315A as well. > > You need to use a resistive splitter and not a tee to control reflections. If you don't have one, make one using 3 resistors mounted in ametal box with a coax connector for each arm/port of the splitter This will work reasonably well if your signal risetimes aren't too short ahnd the component leads arent excessively long. If the 2 cables attached to the tee have the same length you are attempting to drive a 25 ohm load from the source attached to the other arm of the the tee. If the cable delays are mismatched the impedance seen at the tee will be more complex. > I guess I could try using the multiple outputs on the back of the > Spectracom 8140, but that would introduce another variable -- the > outputs may not be exactly in phase. Also, isn't a pulse or square > wave better for doing TI measurements? What the heck. I may try that > just to see what happens :-) > > You may as well just do it to see what happens, but don't expect much better performance. >> Either estimate it (use a circuit simulator) from the input impedance (R >> and C) and the signal transition times or find a TDR (expensive) to >> measure it. >> > > Well, actually I can borrow a TDR. I'll have to read up on how to > measure reflection coefficient with it. The only time I ever used a > TDR was many years ago, in the Air Force. > > Joe Gray > KA5ZEC > It is instructive to vary the TDR transition time and watch the amplitude of any reflections reduce as the risetime increases.
Bruce _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
