National Instruments 370753C-01 Manual De Usuario

© National Instruments Corporation

Figure 4-4.  15-Second Impulse Response

tvec = deftimerange(Sys)

deftimerange( )

 computes a regular time vector (in units of seconds) 

that can be used in time-domain simulations to observe the effects of all or 
most of the input system’s dynamics, as indicated by pole and zero location. 

Within 

deftimerange( )

, the poles of the system are obtained using 

poles( )

. For continuous-time systems, the poles are scaled by a factor 

of 1/2

π (to convert from radians) and the time constant (in seconds) is 

obtained as the reciprocal of four times the value of the pole with the 
maximum absolute value (the “fastest” pole). For discrete-time systems, 
the logarithm of the poles is taken and scaled by the sampling interval. The 
sampling interval is automatically used as the step size for the 

tvec

 time 

vector. If all system poles are integrators, the step size defaults to 0.01.