Filter variations

001_band-pass_filter : Filter variations

Requires: SmartSpice & Smartview

Minimum Versions: SMARTSPICE 4.6.5.R


The SMARTSPICE Rubberband feature allows you to select and modify model, instance and .PARAM parameters, and interactively watch in SMARTVIEW how the simulation changes in real time. To invoke the Rubberband fuctionality you need to:

  • 1. Start SMARTSPICE in GUI mode, or type the command smartspice.
  • 2. Source the input deck.
  • 3. Press the Rubberband button in the Toolbar.
  • 4. Initial run will be started and SMARTVIEW will be invoked.
  • 5. Nominal waveforms correspondent to the original netlist settings will be displayed in green.
  • 6. Select model, device or global parameters for Rubberbanding.
  • 7. Press the Add Selected button in the Rubberband dialog.
  • 8. Move the Rubberband slider from the Sliders tab. The Rubberbanded waveforms will be displayed in red.

This input deck is a Bandpass filter circuit with .AC and .MEASURE analysis.


  • Resistor model parameter r1[res] to change the filter magnitude.
  • Resistor r2[res] to change the phase and bandpass base frequency.
  • Change parameter ".param fc" to change filter centre frequency.
  • Change ".param q" to change Filter Q factor.

The rubber band dialogue shows the r1[res] parameter variation setup and the waveform 1 shows the initial simulation with waveform 2 showing the effect of variation via the slider on the output characteristic.

The output plot w1 shows first case, and w2 shows second, while w3 shows final result.