Schmitt trigger


    Dec 11 2007 | 12:21 am
    Hello i'm trying to implement a Schmitt trigger (http://en.wikipedia.org/wiki/Schmitt_trigger) in the signal domain. It's quite easy to make with non signal objects but i'd like some help doing it with signals.
    I know that the Schmitt trigger is implemented in the 2threshattack~ object but i'd like to know how to construct it with standard objects.
    Thanks,
    John.

    • Dec 11 2007 | 1:17 am
      Hi John
      To gate the amplitude envelop, I'd say a peakamp based solution works nicely, but that obviously is making this solution max based as well, so maybe it's not quite what your after.
      max v2;
    • Dec 11 2007 | 4:39 am
      Hi John,
      thresh~ will fit the bill, and comes with Max.
      Peter McCulloch
    • Dec 11 2007 | 4:56 am
      Thanks Peter,
      I've been trying to brush up on my signal domain chops and had managed to completely overlook the thresh~ object.
      Hi Sebastian,
      Thanks for that but not really what i was after, hope things are good for you.
      John.
    • Dec 11 2007 | 5:38 am
      Also, thresh~ can be pretty interesting for gated amp env. effects
      when paired with slide~ or rampsmooth~.
      Peter McCulloch
    • Dec 11 2007 | 9:40 am
      On 11 Dec 2007, at 04:56, Leafcutter John wrote:
      >
      > Thanks Peter,
      >
      > I've been trying to brush up on my signal domain chops and had
      > managed to completely overlook the thresh~ object.
      hi john,
      here is yet another solution using only standard objects.
      i did this years ago for a project, before thresh~ came to live.
      it's simplicity doesn't reflect the time it took me to come up with
      this solution...
      -volker.
    • Dec 11 2007 | 3:44 pm
      That's a lovely elegant bit of patching volker and it's just the kind of thing i was hoping to see so thanks for sharing it.
      There is a slight issue with it however. If the input changes abruptly from below to above the trigger say from 0-1 (as the output from phasor~ connected to >=~ object might) your abstraction will not trigger. I played about with introducing a one vector delay between the different sides of the signal input to the >=~ and =~ side to go from 0-1 and conversely having a delay in the
      Best to all,
      John.
    • Dec 13 2007 | 6:52 pm
      A co-worker inquired as to the meaning of serendipity this morning.
      I come in here looking for info on Forester2, without finding it.
      Then I clicked this post out of curiosity, and the CutterJohn hiself is behind the curtain.
      Very glad to see it's being worked on.
    • Dec 14 2007 | 2:25 pm
      >
      > There is a slight issue with it however. If the input changes
      > abruptly from below to above the trigger say from 0-1 (as the
      > output from phasor~ connected to >=~ object might) your abstraction
      > will not trigger.
      ah ja. you're right. [sah~] doesn't get retriggered.
      originally this was intended for envelope-signals, i.e. heavily
      lowpassed signals without sharp edges.
      thats probably why the flaw never occred to me.
      havn't used it since [thresh~] came along anyway.
      so we might better let it rest in peace...
      volker.
    • May 28 2010 | 4:52 pm
      Did you ever try to use Schmitt trigger (2threshattack~) and/or bonk~ in an envelope follower. Wouldn't they help in detecting noteOff in the case of reverberant sounds?
      thanks,
      Fabio