Author Topic: Agilent 34905A noob question  (Read 1030 times)

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Offline buton

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Agilent 34905A noob question
« on: March 10, 2013, 01:32:07 am »
Hi guys

Maybe you could help me with this...

i bought this

to expand the inputs on my oscilloscope on a test procedure....

unfortunately  when i hook the signal i am measuring to the agilent mux and i see it on my scope, it seems that it adds and offset and also some deformation... i think i it is due to the fact that my scope input is 1 Mohm and the mux says somethign about 50 Ohm... if that is the case how do i fix it?



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Re: Agilent 34905A noob question
« Reply #1 on: March 10, 2013, 01:40:38 am »
The only way to get decent signal integrity (SI) with that thing is to go 50 ohm: terminate the signals from the mux in 50 ohm at your scope, using (in order of decreasing SI) the internal termination if present, a feed-through 50 ohm terminator, or a BNC tee with 50 ohm terminator. You will also need to feed the mux from a 50 ohm source, for example a 50 ohm signal generator, an active probe designed for 50 ohm inputs, or a restive divider probe as for example described by Howard Johnson or Doug Smith. Neither of these options are very nice for general-purpose low-frequency probing (eg. power supplies, audio).

Offline KJDS

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Re: Agilent 34905A noob question
« Reply #2 on: March 10, 2013, 02:20:57 am »
What sort of signals are you probing, and does your scope have 50ohm input capability?

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