trig_cross :
A trigger generator for an xreal-typed signal’s crossing events.

The trig_cross primitive generates an xbit-typed trigger out when an xreal-typed signal in has the (N+k*P)-th event crossing a given threshold after a specified delay, where k is 0, 1, 2, and so on. The threshold, triggering count N, period P, and delay are defined by the parameters threshold, times, period, and delay, respectively. When the parameter times is less than or equal to 0, the primitive triggers out whenever in crosses the threshold after the delay. The parameter direction specifies whether the primitive detects the rising events only (+1), falling events only (-1), or both (0).

The xbit-typed trigger out can be used as an input to the measurement primitives to measure the time instants, delays, periods, etc. of the triggering events. The trigger signal is initialized to X and changes to 1 when the first event occurs. The trigger output out then toggles to a different value (0 or 1) whenever a subsequent event occurs.

Input/Output Terminals

Name	I/O	Type	Description
out	output	xbit	output trigger
in	input	xreal	input signal

Parameters

Name	Type	Default	Unit	Description
threshold	real	0.0	None	threshold level
direction	integer	0	None	crossing direction
delay	real	0.0	seconds	triggering delay
times	integer	0	None	triggering count
period	integer	0	None	triggering period