AC coupling cut off frequency in Oscilloscope

engr_joni_ee · Apr 12, 2022

Hi,

I am wondering what is the cut off frequency of AC coupling in this Oscilloscope PicoScope 5444D and 5444D MSO 4-channel, 200 MHz.

KlausST · Apr 12, 2022

Hi,

just switch it to "AC", input a Dc voltage and watch the step response.
Measure tau (= until 63% of DC voltage)

fc = 1/(2 * pi * tau)

Klaus

crutschow · Apr 12, 2022

KlausST said:
just switch it to "AC", input a Dc voltage and watch the step response.
Measure tau (= until 63% of DC voltage)

For determining the low-frequency cutoff you would measure when the step input drops to 37% of the peak value to get tau (time-constant).

KlausST · Apr 12, 2022

Hi,

~~63% rising, 37% falling .. where is the difference?~~

Oh yes, it´s a high pass. For sure. You are right.

Klaus

FvM · Apr 12, 2022

My Agilent/Keysight 6000 has 3.5 Hz high pass corner. Unfortunately Picoscope manual and datasheet don't specify.

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