.Measure Commands - Fall 2013

The .Measure commands, popularized by HSPICE, are now available in Micro-Cap11. .Measure commands are a set of tools that, like performance functions, make measurements on curves generated by the analyses. .Measure commands are similar to those used in other simulators. Their inclusion in Micro-Cap is intended to make it easier for users familiar with them. Many of the functions used in the .measure commands are also available as Performance functions. .Measure statements can be easily built using the Build command within the text dialog box. This convenient dialog box lets you fill in the blanks and it creates the .Measure statement for you. You can see .measure variables by 1) Plotting them in the analysis. Values are computed at the end of the analysis and then plotted as straight lines. 2) Viewing them in the Scope Menu / Measurements window. 3) Printing them in analysis text as in Delay1= [dly1] where dly1 would be a defined result variable from a .measure command. Don't forget to check the Formula option in the Text dialog box when creating the text. Note that there are a group of .measure functions stored in the measure.lib and these are available to any circuit. Users may add to these as needed. Note also that .measure functions are extensible. Unlike Performance functions, they can be extended and new ones invented as needed. Here are some examples of the .Measure command: .MEASURE TRAN SUM1 AVG V(1)*2 FROM=0 TO=1000N This example computes the average of the expression V(1)*2 from 0 to 1000n in transient analysis and assigns the value to SUM1. .MEASURE TRAN IN1 INTEG V(V1)*I(V1) FROM=200n TO=1000N This computes the integral of the expression V(V1)*I(V1) from 200n to 1000n in transient analysis and assigns the value to IN1. .MEASURE TRAN BIG MAX V(OUT)/2 FROM=1E-7 TO=1E-6 This computes the largest value of the expression V(OUT)/2 from 1e-7 to 1e-6 in transient analysis and assigns the value to BIG. .MEASURE TRAN SMALL MIN V(IN1) FROM=1E-3 TO=1E-2 This computes the smallest value of the expression V(IN1) from 1e-3 to 1e-2 in transient analysis and assigns the value to SMALL. .MEASURE TRAN PP1 PP V(OUT) FROM=0 TO=5U This computes the peak-to-peak value of the expression V(OUT) from 0 to 5u in transient analysis and assigns the value to PP1. .MEASURE TRAN RR1 RMS V(IN) FROM=0 TO=5U This computes the RMS value of the expression V(IN) from 0 to 5u in transient analysis and assigns the value to RR1. .MEASURE AC DD1 DERIV V(out) AT=1e6 This computes the derivative of the expression V(OUT) at F=1E6 in AC analysis and assigns the value to DD1. .MEASURE TRAN DERA DERIV V(A) WHEN V(A)=V(B) CROSS=3 This assigns the value of the time derivative of the expression V(A) to DERA when V(A)=V(B) for the third time in transient analysis. Well, you get the idea. Micro-Cap 11 adds to the basic idea of .measure commands by allowing the use of extensible libraries of these functions and by automatically displaying many of then in a Measurements window.