I want some information abt ALL pass filter circuit.Can u suggets me any link or any book wherre i can hav sufficient information about it

xcept http://en.wikipedia.org/wiki/All-pass_filter.

 

Here is the Wikipedia reference - http://en.wikipedia.org/wiki/All-pass_filter. If the phase shift is not a concern, then a conductor, like a wire, will pass all frequencies.

 

Try this active filter application note. There is a section near the end of the document that covers All-pass filters.

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