## Schmidt trigger

Scope and XITE Development

Original topic on PlanetZ: https://forums.scopeusers.com/viewtopic.php?t=27530

#### Schmidt trigger

Posted: Tue May 26, 2009 5:55 am
by eric
Is there such a device in the SDK?
I am anxiously waiting for the postman to bring me the SDK paperwork from Ralf...
in the meantime -
I want to take the beat frequency between 2 oscillators (at low frequency), feed through a Schmidt trigger to trigger an envelope. Can it be done or is the Schmidt trigger redundant?
Eric.

#### Re: Schmidt trigger

Posted: Tue May 26, 2009 6:13 am
by Neutron
all that is is a gate which is triggered at a higher level than it releases, (it has hysteresis)
are you trying to have the beat frequency actually turn the envelope on and off? why would you do that

#### Re: Schmidt trigger

Posted: Tue May 26, 2009 6:35 am
by eric

> Neutron wrote:all that is is a gate which is triggered at a higher level than it releases, (it has hysteresis)
> are you trying to have the beat frequency actually turn the envelope on and off? why would you do that

Yes I want to turn the envelope on and off with the resulting square wave produced by the Schmidt trigger. The beat from the 2 oscs would pass through a low-pass filter then be squared up by the Schmidt. Does an envelope generator require fast leading/trailing edges or could you feed it the waveform from the low-pass filter and let it trigger when the level is high/low enough? (In an electronic circuit, this wouldn't be repeatable or predictable enough.) In emulation maybe you can't connect an audio source to a trigger destination.
As for why - why not?
Eric.

#### Re: Schmidt trigger

Posted: Tue May 26, 2009 6:40 am
by Neutron
you have to change the resulting signal to a "gate" i believe it would work without anything else, that stuff usually works on zero crossing.
or you can just use an envelope follower set to very fast attack and decay, on a low enough frequency it will just turn on and off and you can adjust the threshold.

#### Re: Schmidt trigger

Posted: Tue May 26, 2009 5:29 pm
by eric
Thanks.
I guess it will all become clear when SDK arrives.
Eric.