Why does longer probe cable reduces bandwidth

[00135599]

Why does longer probe cable reduces bandwidth of the probe? Does it mean the higher frequencies won't be transmitted? Is the reduction applied always only on higher frequencies? Why? What's the physic of this?

 

[OLIVE2222]

It's due to the cable capacitance who is proportional to the length.

nice info here:
http://circuitslab.case.edu/manuals/Probe_Fundamentals-_Tektronix.pdf

 

[00135599]

It's due to the cable capacitance who is proportional to the length.

nice info here:
http://circuitslab.case.edu/manuals/Probe_Fundamentals-_Tektronix.pdf

I was reading this document, when found the note about reducing bandwidth of the probe with longer cable. I will continue reading, then, and try to find explanation later in the text. Thanks.

 

[Arouse1973]

It's due to the cable capacitance who is proportional to the length.

nice info here:
http://circuitslab.case.edu/manuals/Probe_Fundamentals-_Tektronix.pdf

If its distributed capacitance then within reason how does this matter versus length?
Adam

 

[Merlin3189]

I think this is why you use a x10 probe on the end of the cable. Then you can adjust the serial capacitor to match the cable (& input) parallel capacitance.
Without a probe with serial capacitor, there is only parallel capacitance, which attenuates signals proportional to frequency and this effect is worse the longer the cable.

 

[Arouse1973]

Yes and its series capacitor. And this is the reason x1 probe has lower bandwidth because you have shorted out the capacitor at the tip.
Adam