One thing I noticed about third party 1 MOhm passive probes faster than 100 MHz
is that besides the compensation adjustment, they include (or should include) a
whole set of transient response adjustments. During tests with my 2440, the
response of the general purpose replacements probes I bought for it was
indistinguishable from the 50 ohm terminated response.
Of course calibrating the probe and oscilloscope combination is not trivial
since it requires a flat level pulse generator with a fast enough transition
time and a coaxial attachment to the probe.
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On 28 Feb 2014 16:02:46 -0800, you wrote:
Yes, it does matter if you want to take advantage of the maximum bandwidth.
Tek passive probes over about 200 MHz are designed for a specific series of scope. The intermediate time constants in the compensation network have elements that are tuned to compensate for the parasitic elements in the scope attenuator system. These are mostly associated with the physical construction of the attenuator, including the relays, and elements on the hybrid circuit. The tend to be very consistent from scope to scope of the same model, but because different designs are used in different models, they change considerably between models.
These effects minimize the overshoot and "wrinkles" in the first 2 ns of the rising edge and flat top. Minor differences will only result in a "bump" where it is not suppose to be. Larger differences will result in considerable overshoot or slow "bleedup" on the front corner of the pulse. (for instance, don't consider using the P6139A on a 2465 - there us a huge difference)
If you don't care about the high frequency performance, then any probe will work assuming the LF comp range is sufficient. But if this is the case, why did you spend the extra money on a 2465B?
- Steve
David Hess