Use this component to model a linear voltage-controlled voltage source system by specifying only its frequency response, using a dataset of frequency and gain values.

The Value tab in this component's properties dialog box contains the following:

  Parameter   Description
Data is in Magnitude, Phase format

Select if you want the data triplets in the Data Set table to specify Frequency, Magnitude, Phase.

Select the Magnitude units and Phase units from their drop-down lists.
Data is in Real, Imaginary format Select if you want the data triplets in the Data Set table to specify Frequency, Real, Imaginary.
Data Set

Enter the frequency response Data Set in this box as a set of triplets, observing the following:

  • The frequency value data must be increasing.
  • The three values in each set must be separated by commas and each triplet must be enclosed in round brackets ().
  • You may continue entering triplets on new lines.
  • You may optionally include the + character at the start of a line (this provides compatibility with data copied from netlists).

Below are some examples:


(1hz, 0, 0)(100hz, -3, -30)(1k, -60,-90)
Or
+(7.1856161442629572e-003,-2.6898268451516408e+001,8.7408111189598031e+001)
+(7.2238027778448975e-003,-2.6852139445187749e+001,8.7394682771649656e+001)
+(5.8627499123103019e+002,-7.1321612855946114e+001,-8.9984428926657671e+001)
+(5.8947568929612930e+002,-7.1367650199523553e+001,-8.9984509480742716e+001)
+(5.9267638736122842e+002,-7.1413932853066413e+001,-8.9984590895581846e+001)
+(5.9587708542632754e+002,-7.1460463444853644e+001,-8.9984673185045423e+001)
+(5.9907778349142654e+002,-7.1507244645631289e+001,-8.9984756363303461e+001)
+(6.0227848155652566e+002,-7.1554279169532393e+001,-8.9984840444833736e+001)
+(6.0547917962162478e+002,-7.1601569775021844e+001,-8.9984925444430147e+001)

You can use Multisim's standard number format. Refer to the Multisim SPICE Reference section for information.

During simulation, Multisim uses interpolation to determine the missing values. The magnitude is log-interpolated while the phase is linearly interpolated. Values outside of the frequency range specified in the Data Set are taken to be those of the nearest specified frequency.
Group delay (sec) Reduces the slope of the phase.
Custom accuracy

In a time domain simulation, the Frequency Table Function component uses impulse response and a convolution technique to process the input. The impulse response is obtained from the sampled frequency response (using an inverse Fourier Transform).

Two parameters control the sampling: the maximum frequency sampled and the frequency sampling resolution. By default, Multisim automatically chooses these parameters based on both the simulation settings (TSTOP and TMAX) and the frequency response characteristics (smallest dataset frequency difference and maximum dataset frequency).

Due to computational constraints, the following restriction exists:

Frequency Resolution > 2*Maximum Frequency / 65536

If the above constraint is not met, then the Frequency resolution is set to:

2*Maximum Frequency / 65536.

In addition, to prevent an unncessary truncation in accuracy, the following restriction exists:

Frequency Resolution < 2*Maximum Frequency / 512

If the above constraint is not met, then the Frequency resolution is set to:

2*Maximum Frequency / 512.

Multisim also makes a conservative adjustment to any specified Frequency resolution value such that the ratio of 2*Maximum Frequency and Frequency Resolution is a power of 2.

The sampling values which are actually used to calculate the impulse response are reported in the Simulation Error Log/Audit Trail.

Refer to the Simulation Error Log/Audit Trail section for more information.