Note: In SPICE, the command that performs an AC Analysis has the following form: For Linear, is the total number of points spaced evenly from the start to the stop frequency.Ĭontrols the y-axis scaling on the output graph. For Decade/Octave, is the number of points per decade/octave. Its interpretation depends on the Sweep Type. Indicates how the analysis frequency is swept. It must be greater or equal to the starting frequency. It must be greater than zero.Įnding frequency of the frequency sweep.

Starting frequency of the frequency sweep. Table 1 describes the Frequency Parameters tab in detail. The additional settings in the Value tab are used for other analyses or for simulating with the instruments. In this exercise you will use the default values, 1V and 0°, respectively.

If you want to perform the analysis with specific values for magnitude and phase, double-click the input source, Vin, go to the Value tab and enter values for AC Analysis Magnitude and AC Analysis Phase. The circuit will attenuate frequencies greater that 500 Hz. Experiment with different values to see the circuit’s behavior.

Stop the simulation and change the frequency of the AC_VOLTAGE source, Vin.

Open the Oscilloscope front panel and run the simulation.

Open circuit file butterworth_filter.ms11 located in the Downloads section.

You will use AC Analysis to determine its frequency response.Ĭomplete the following steps to configure and run an AC Analysis: This is a fourth-order Butterworth low-pass filter with a cutoff frequency of 500 Hz and a passband gain of 10 (20 dB) this circuit was taken from. Digital components are treated as large resistances to ground.Ĭonsider the circuit shown in Figure 1.

AC circuit response is calculated as a function of frequency.Īssumptions: The analysis is applied to an analog circuit, small-signal.

If the Function Generator is set to a square or triangular waveform, it will automatically switch internally to a sinusoidal waveform.

All input sources are considered to be sinusoidal, their frequency is ignored.

Nonlinear components are represented by linear AC small-signal models, derived from the DC operating point solution.

AC sources, capacitors, and inductors are represented by their AC models.

Multisim constructs this matrix using the following approach:

A complex matrix, containing both real and imaginary components is created.DC operating Point Analysis is performed to obtain the small-signal models.Multisim performs AC Analysis using the following process: The result of an AC Analysis is displayed in two parts: gain versus frequency and phase versus frequency. Then, the equivalent circuit is analyzed from a start to a stop frequency. In AC Analysis, the DC operating point is first calculated to obtain linear, small-signal models for all nonlinear components. AC Analysis is used to calculate the small-signal response of a circuit.

Bode plots multisim