Thanks for clarification. In this case standard 10:1 passive probe or active probe should be used. 10:1 probe has typically 10-20 pF input capacitance. If the amplifier can work with this load, there's nothing against this solution. Proper ground connection is of course necessary, as discussed before.My designed amplifier can support load of 10k Ohm, but 1k Ohm is little difficult
Typical resistive probe doesn't use source side termination, it's relying on good load termination in oscilloscope to keep reflections small. I've used original Tektronix as well as self elaborated resitive probes for GHz bandwidth with good results.Or you can use a passive probe with built in divider.
FvM talked about 950 Ohms / 50 Ohms divider.
This solution results in
* a 1000 Ohms load to the signal (usually no problem to drive. Causes just minor modifications)
* a 47.5 Ohms source impedance ( 950 Ohms || 50 Ohms) for properly driving the cable.
* the voltage to be divided 39:1 (HF, properly terminated)
(50 Ohms of the resistor divider in parallel to the 50 Ohms characteristic impedance)
True.Typical resistive probe doesn't use source side termination, it's relying on good load termination in oscilloscope to keep reflections small. I've used original Tektronix as well as self elaborated resitive probes for GHz bandwidth with good results.
SorryKlaus the last post has by mistake submitted before I finish it, please you can refer to it back. Yes you are right, I am testing now with pulse and sine wave, sure the square wave has more bandwidth depending on its fundamental frequency and also on the rising and falling edge speed.Hi,
10MHz sinewave. This is completely different to the scope pictures of post#1.
If you consider a signal speed (acble) of about 200 million meters / s then 10MHz give a wavelength of 20m.
1MHz about 200m.
Since the characteristc impedance of a cable gets full effect when 1 fullwave "is in the cable", this means you need a 20m cable.
For sure the charactereistc impedance also has impact on shrter cables. But is relevant from 10% or 20% of wavelength.
Bot do not match your new requirements.
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10MHz sinewave is a completely different task than 10MHz square wave because of all the overtones.
Klaus
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