[sci.electronics] odd filter wanted

mcdonald@aries.scs.uiuc.edu (Doug McDonald) (04/30/91)

I'm looking to see if someone sells some reasonable approximation
to an electrical filter network I need. I know perfectly well how to
kludge one together, but is a mess involving several delay lines
(I would use lengths of coax.)


What I need is a filter with a time response that is about 30
nanoseconds wide FWHM and has either a rectangular time response
(or a reasonable trapeziodal approximation) or a Gaussian response.


Anybody have any ideas?

Doug McDonald (mcdonald@aries.scs.uiuc.edu)

whit@milton.u.washington.edu (John Whitmore) (05/01/91)

In article <1991Apr30.003318.12397@ux1.cso.uiuc.edu> mcdonald@aries.scs.uiuc.edu (Doug McDonald) writes:

>What I need is a filter with a time response that is about 30
>nanoseconds wide FWHM and has either a rectangular time response
>(or a reasonable trapeziodal approximation) or a Gaussian response.

	Depending on what bandwidth you want, perhaps you should consider
a multi-tap delay line?  Terminate it correctly, and just sum
over 30 ns worth of taps (with appropriate buffering so your taps
aren't loaded).  The LCB030Z100, from Allen Avionics, is a 100-ohm
delay line with 20 equal-spaced taps, good for 120 MHz bandwidth.

	Allen Avionics 
	(516) 248-8080

Other manufacturers may have something similar (Hey, I just opened the 
EEM and flipped to the delay lines section... and AA was first.).

	Hope this helps.

	John Whitmore