Please see attached filter output display using LTspice, with AD8616 opamps. The filter is a pair of cascaded 8th order butterworth bessel bandpass filters, total 30dB gain. (Need very strong rejection out of band) Unfortunately, even with minimal delay filters, delay *is* happening with a 16th order filter.
So...the question is this: With this filter/gain stage ahead of a AD8307 (yes, gain has been accounted for in output) what will the impact be when detecting a very short signal burst of, let's say duration 60ms? 100ms?
By T = 200ms, the filter has reached almost full magnitude. Does this mean that for any signals bursts under approximately 125ms, will not be seen at all by the AD8307 ? Or are they just delayed and will not reach the output (and be of significant amplitude) for a time period > approximately 125ms?
Thanks for your help !!