Yep I have a similar problem - this is what I do:
(I presume your sawtooth is in an array?)
If your sawtooth samples is N, make a new array with n+1 samples
copy the original to the new array right shift it one place. Add an
empty element to the begining of the original array - then subtract the
two arrays. This gives the difference between successive samples, the
falling edge should show up quite clearly. Then do a max value of the
difference array - take a value 50% down on this and produce a new
boolean array with a zero value if less than 50% and a value of one if
greater than 50%. You *should* get a pulse waveform whose peaks coincide
with the falling edge (you may have to watch the sign of the difference
array).
I do this to measure the frequency of a rounded squ
are wave with DC
shift - works for me!
Good hunting!
In article <37394641.2467@stud.fh-regensburg.de>, juergen.dachs@stud.fh-
regensburg.de writes
>Hi all,
>I recently encountered the following problem:
>I have a sawtooth waveform sampled from an oscilloscope and I need to
>detect the falling edge of the sawtooth signal.
>I first thought of using the "peak detect" function, but this fails
>since there is some jitter on the signal and sometimes an even larger
>peak after the falling edge, which "peak detect" will find.
>
>Any mathmathical interessed LV's around, who know how to find the
>falling edge of a sawtooth, in spite of jitter and later peaks ?
>
> Thx
> Jürgen
>
>
>Jürgen Dachs
>Infineon Technologies
>
>email: Juergen.dachs@infineon.com
--
Pete Barnes
