Noise Simulation

Understanding LTspice : Noise Simulation

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Noise Simulation Analysis

Ltspice can perform frequency domain noise simulation analysis which takes into account shot, thermal and flicker (1/f) noise. The resulting noise density (in units of volts per square root hertz) can then be plotted to aid in circuit analysis and understanding. These noise calculations are performed at each frequency step and can be plotted in probe.

The two types of noise are:

  • Output for noise on the outputs and
  • Input for noise on the input source.
  • Type of Sweep (same as for AC analysis)
  • Number of points… (same as for AC analysis)
  • Start Frequency (same as for AC analysis)
  • Stop Frequency (same as for AC analysis)

In order to set up up a simulation click on the “Simulate” menu and followed by “Edit simulation Command“. Otherwise you can right click on the existing simulation command below and select the noise tab from the pop up menu. In the pop up window you need to provide the values, See the below figureNoise Simulation

    • Type of sweep – Decade
    • Number of point per decade – 100
    • Start Frequency – 100 Hz
    • Stop frequency – 40Meg
    • Input source – Vin_source
    • Output – V(Vout)

Then click OK. To run the simulation click Simulate –> Run or right click and select Run.




Now move your cursor to the output node and clicking on it. You will see the nose frequencies plotted in the simulation window. Refer the below image.Noise Simulation

Hope this article helped you in understanding LTspice better. Do write your comments and suggestions. Happy reading …

 

 




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