Malcolm Lidierth

Correction: Should read: Chebyshev I (not II) and odd-ordered to provide unity gain in the passband (within Apass dB) and odd-ordered to produce no shift in mean (therefore, if I recall, 0dB gain at zero Hz) as documented in wvDecimate. This code was written 10 years ago (so applies to old MATLAB versions) and info on MATLAB's filter implementation may be out-of-date: There's a reference to TMW Technical Solution 1-2YWEQD but that seems no longer to be available.

Corretion: Should read: Chebyshev I (not II) and odd-ordered to provide unity gain in the passband (within Apass dB) and odd-ordered to produce no shift in mean (therefore, if I recall, 0dB gain at zero Hz) as documented in wvDecimate. This code was written 10 years ago (so applies to old MATLAB versions) and info on MATLAB's filter implementation may be out-of-date: There's a reference to TMW Technical Solution 1-2YWEQD but that seems no longer to be available.

OK. The best thing is always to reduce noise at source. That's not always easy in a theatre but the Digitmer HumBug device might be your next best option if collecting more data. It removes 50Hz and harmonics. If you have Spike2 smr files, you can remove 50Hz subtractively using a script in Spike2 written by CED. Drop them an email - they are always very helpful. It won't be as good as the HumBug which uses fast sampling real-time processing. You need an analgue filter to avoid aliasing before sampling....

Elisa Notch filters are pretty horrible things, whether analogue or digital, and introduce all sorts of distortions. You can design one in MATLAB using the standard Mathworks GUIs (fdatool or filterDesigner at the ML prompt) where they are called 'bandstop' filters. Distortion will increase with higher attentuation and narrow notches. Your data collection software provider may provide an option to subtract rather than filter away mains interference (e.g. CED). Better still, hardware to do that is...

Ah. Now resolved, I hope.

Apologies if you have received a dozen or so out-of-date emails. It seems the subscription...

PDF support depends on Apache Batik which ships with MATLAB. There are some issues,...

It's on Github: shadowed on SourceForge website but perhaps not getting accessed...