Accelerometry design filter and outline

Hi, would like to ask 2 vinculated questions:

1) Need to know wich is the right design for an accelerometry filter

I have desing one myself, (attending several researches):

Fs = 100; % Sampling Frequency

• Fstop1 = 2; % First Stopband Frequency
• Fpass1 = 3; % First Passband Frequency
• Fpass2 = 7; % Second Passband Frequency
• Fstop2 = 8; % Second Stopband Frequency
• Astop1 = 60; % First Stopband Attenuation (dB)
• Apass = 1; % Passband Ripple (dB)
• Astop2 = 80; % Second Stopband Attenuation (dB)
• match = 'stopband'; % Band to match exactly

Is this right?

2) The result can be seen in ths plot:

I have already smoothed the data, but as you can see, there are still many peaks. Is there anyway to outline better those peaks

Thank you

[Star Strider]

Consider decreasing ‘Fpass2’ and ‘Fstop2’ since they are obviously not filtering out the high-frequency noise.

To design the filter a bit more scientifically, calculate the fft of the time-domain signal first, then use that information to determine the optimal filter passband and stopband frequencies. (Since the signal may have a d-c offset, subtract the mean of the signal first, before claculating the fft, to show the other peaks more clearly.)

[Julio Martín]

Thank you, it's fine!

[Julio Martín]

Does not appear accept button, do you know why?

[Star Strider]

The Accept button does not appear because I posted it as a Comment, not an Answer. I have now posted it as an Answer, so it can now be accepted.

Thank you!

.

Answer 1

[Star Strider]

Consider decreasing ‘Fpass2’ and ‘Fstop2’ since they are obviously not filtering out the high-frequency noise.

To design the filter a bit more scientifically, calculate the fft of the time-domain signal first, then use that information to determine the optimal filter passband and stopband frequencies. (Since the signal may have a d-c offset, subtract the mean of the signal first, before claculating the fft, to show the other peaks more clearly.)

[Julio Martín]

Thanks!

[Star Strider]

As always, my pleasure!

Thank you!

.