I seem to remember on the old board that during a discussion about enveloping that there was a rule of thumb statement about the hi pass filter setting. I can't remember if it was said the filter should be less than Fmax, equal to Fmax or greater than Fmax. Can anyone fill in my blanks?

dj

The low frequency cutoff of the pre-demodulation high pass or bandpass filter should be greater than the maximum frequency of the intended envelope spectrum. If you use a bandpass filter on the input, its bandwidth should generally be at least 4 times the intended maximum frequency of the output envelope spectrum. For real world applications, neither of these is usually a problem.

This message has been edited. Last edited by: Duncan Carter,

If you are using the Microlog series data collector from SKF, the lower end of the filter band does not have to be greater that your Fmax setting.