That's a bit unusual actually... normally there would be a control for threshold or other trigger options like delay, window length, pulse selection and so on for more advanced scopes.ENV1 wrote:The 'Modular' variant of s(M)exoscope has a third input (plus the trigger-option 'External') for just that purpose.aciddose wrote:...you'd need a separate "sync input" on the scope which would come from the raw unfiltered root frequency waveform such as a sub oscillator.
For some reason the external trigger signal needs to be rather high-amplitude (otherwise the scope wont trigger/refresh) but once everything is dialled in right it pretty much does what youd expect.
There may be others that have this functionality but im not aware of any.
In the general case it's a "zero crossing detector" which triggers where you have a postive-going (or negative-going) impulse that crosses the threshold voltage. That's normally adjustable with a knob labelled trigger "level" or similar.
People often complain about some of these tools being "too complicated" so I'd be surprised if s(M)exoscope doesn't have the trigger level control somewhere there.