Do you need the rise and fall times to be adjustable or just shorter
(faster) than some value? If the latter, I would recommend looking at logic
gates to "square up" your signal. 74AC or 74AHC series should easily be
able to deliver <2ns rise/fall times. You may want to use schmitt trigger
versions, too. There are probably even more modern ones that can do even
better. What is your load for this signal? Any capacitance in the load will
make this more challenging and may require paralleling of several gates to
have sufficient drive.


On Thu, Jul 4, 2013 at 1:41 PM, Yigit Turgut <y.turgut@gmail.com> wrote:

> Hi collective brain,
>
> I want to generate a pulse/square signal with a few nanoseconds of
> rise/fall times. I did this with various PIC's and with FPGA's and I got
> around 2ns of rise/fall times which is good but I need to make it simpler
> (cheaper).
>
> Now I am trying to implement the same with completely analog components ;
>
>  width ; adjustable between 2ns-10ns
>  frequency ; adjustable between 1Hz-200Hz
>  amplitude ; adjustable between 5V-12V
>
> I know there are some defacto ways to do this but I feel rusty on the
> analog side and would appreciate the guidance of analog experts here. I
> know you are out there, don't hide!
>
> Yigit
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