Bandpass filter for WaveForms oscilloscope with Analog Discovery 2

[Hiroki Tamakoshi]

I'm using Analog Discovery 2 and WaveForms 3.7.5 on macOS 10.13.

It works perfectly as expected, and I want to cut the fluctuation below than 0.1Hz and the power supply noise(50Hz).

Is it possible to add a bandpass filter to pass between 0.1 and 50Hz to the oscilloscope?

[attila]

Hi @Hiroki Tamakoshi

See the Scope/ Add Channel/ Math/ Filter

[Hiroki Tamakoshi]

11 hours ago, attila said:

Hi @Hiroki Tamakoshi

See the Scope/ Add Channel/ Math/ Filter

Thank you attila! This is exactly what I wanted to do. I couldn't set the lowest frequency lower than 1Hz, but it works for me currently.

Just one more question: the filtered result dips deeply at the early phase as the attached image shows. I want to avoid this phenomenon. Is it possible?

[attila]

Hi @Hiroki Tamakoshi

Could you save and post the workspace to see the raw captured data?

[Hiroki Tamakoshi]

Hi,

Here's the workspace I saved.

with best regards,

default.dwf3work

[attila]

Hi @Hiroki Tamakoshi

I don't think we can do anything about the leading data in time domain. It looks like the filter needs significant amount of data for initialization.
You could eventually use only the second, stabilized part of the time data.
On the other hand the frequency response looks perfect for the whole data range.
BTW: WF v3.7.22 lets you set filter frequency lower than 1Hz: https://forum.digilentinc.com/topic/8908-waveforms-beta-download/