The present syntax supported by the .measure command in WRspice is a super set of the previous syntax cases, which are shown below. These should all work in the present system.
Form 1 is straightforward; the interval starts (trig) or ends (targ) at value. Value must be within the simulation range of the scale variable (e.g., time in transient analysis).
The same effect can be achieved with:
trig|targ variable [val=]value [td=delay] [cross=crosses] [rise=rises] [fall=falls] [minx=min_delta]
Form 2 allows the interval boundaries to be referenced to times when a variable crosses a threshold. The variable can be any vector whose value is available during simulation. The value is a constant which is used to measure crossing events. The val= which precedes the value is optional. At least one of the rise/fall/cross fields should be set. Their values are integers which represent the variable crossing the threshold a number of times. The rise indicates the variable rising through the threshold, fall indicates the variable decreasing from above to below the threshold, and cross indicates rises + falls. If given, the minx value sets the minimum time delta between the crossing events, those that occur too soon are ignored. This can be used to suppress false triggering from ringing or noise. The interval boundary is set when the specified number of transitions is reached.
If the delay is specified, transition counting starts after the specified delay.
This indicates that the interval begins at the second time v(2) rises above 2.5V after 0.1ns.
trig|targ when expr1=expr2 [td=delay] [cross=crosses] [rise=rises] [fall=falls] [minx=min_delta]
The third form is similar to the second form, except that crossings are defined when expr1 = expr2. These are expressions, which must be enclosed in parentheses if they contain white space or commas. A rise is defined as expr1 going from less than to greater than expr2.