.VEC statement use

004_dot_vec : .VEC statement use

Requires: SmartSpice & Smartview

Minimum Versions: SMARTSPICE 3.16.12.R

Example 4 illustrates the AC magnitude response of the 2-pole Chebyshev Low Pass Filter schematic. The example uses the JFET-based LF356 operational amplifier. The Chebyshev magnitude response in db is shown from the magnitude.png waveforms screenshot to change as the poles of the filter are changed.

There are several ways to do this in SPICE, but a common method is to use a form of parametric analysis. In this example, the .ST statement is used to modify the capacitance value of C1 which is increased from 0.8uF to 1.2uF in steps of 0.1uF. The five magnitude responses from these values can be seen in the plot.