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Dynamic AC Current Source: AC_I

Symbol

Summary

AC_I is a versatile AC current source that encapsulates the functionality of many AC current sources into a single AC current source. A variety of signal types may be generated with this source, including sinusoid, piecewise linear, pulse, saw, square, and triangle signals. In addition,you can specify what to use for frequency, how to calculate bandwidth/number of harmonics, the tone number, and how to sweep voltage.

This source combines the functionality of the following current sources: ACCS, ACCS2, ACCSN, ACCSNS, ACCSS, I_PLS, I_PWL, I_SAW, I_SQR, and I_TRI.

Parameters

Name Description Unit Type Default
ID Current source ID   I1
Signal Signal type   Sinusoid
SpecType Specify type   Use doc freqs
SpecBW Specify bandwidth   Use doc # harms
Sweep Current sweep type (only used when Signal=Sinusoid)    
Tone Tone number for the signal   1
DCVal DC value (used for DC analysis) Current 0 A
*Hint Hint   Auto
*NSamp Over sample factor   1

* indicates a secondary parameter

Parameter Details

Signal. Specifies the signal type as "Sinusoid", "PWL", "Pulse", "Saw", "Square" or "Triangle".

SpecType. Specifies whether to use the document frequencies or specify a frequency or time period. Choices are "Use doc freqs", "Specify freq", "Specify period", "Trans only (Freq)", or "Trans only (Period)". The Trans only settings can only be used with transient simulators.

SpecBW. Specifies whether to use the number of harmonics in the document settings or to specify the number of harmonics or minimum time resolution. Choices are "Use doc # harms", "Specify # harms" and "Min time res".

Sweep. Specifies whether power is swept. Choices are "None", "Vector", "Linear", "Linear (# pts)", "Log (Dec)" and "Log (Oct)".

Tone. Tone number for the signal.

DCVal. DC current value used for DC analysis.

Hint. If the type of signal is known (large signal or small signal), the solvers can take advantage of this hint to help solve the problem in the most efficient way. Choices are "Auto", "Large signal" and "Small signal".

NSamp. Oversample factor. This sets the oversampling factor at the specified tone. Specify a value of zero to indicate that this parameter does not override the value specified for the Tone X Over Sample in the project or document harmonic balance settings. (Choose Options > Default Circuit Options and click the AWR Sim tab.) This only applies when the Tone parameter is set to 1, 2, or 3 for the element. An error is issued if this parameter is set to zero for a source with Tone equal to 4 or more.

Dynamic Parameters

Name Description Unit Type Default
Mag AC current magnitude Current 1000 mA
Ang AC current angle Angle 0 Deg
Freq Frequency for tone N Frequency 1 GHz
Period Period Time 1 ns
NHarm Maximum number of harmonics for this tone   5
MinRes Minimum time resolution Time 1 ns
IStart AC current start Current 0 mA
IStop AC current stop Current 5000 mA
IStep AC current step Current 1000 mA
NumPts Number of swept current points   2
Offset Waveform offset (does not affect DC) Current 0 mA
WINDOW Window type    
TIME Time vector Time {0,0.5,1} ns
CURRENT Current vector Current {1000,1000,1000} mA
HI High current level Current 500 mA
LO Low current level Current -500 mA
TD Time delay Time 0 ns
TW Pulse width Time 0 ns
TR Rise time Time 0 ns
TF Fall time Time 0 ns

Dynamic parameters are parameters whose existence depends on the settings of the static parameters. The following is a list all of possible parameters that may display for the AC_I depending on the settings of the static parameters Signal, SpecType, SpecBW and Sweep.

Dynamic Parameter Details

Mag. Displays when Signal is "Sinusoid" and Sweep is "None" or "Vector". If Sweep is "None", only a single current value is specified. If Sweep is "Vector", each value represents a value in the current sweep.

Ang. Displays when Signal is "Sinusoid". Represents the relative angle of excitation. If Sweep is "None", only a single angle value is specified. If Sweep is "Vector", each value represents the angles of each value in the current sweep.

Freq. Displays when SpecType is "Specify freq". Allows you to specify a single source frequency directly on the port instead of having to use the document or project frequencies.

Period. Displays when SpecType is "Specify period". Allows you to specify the time period of the source signal directly on the port instead of having to use the document or project frequencies.

NHarm. Displays when SpecBW is "Specify # harms". Allows you to specify the number of harmonics to use directly on the port instead of having to use the document or project setting. Specify a value of zero to indicate that this parameter does not override the value specified for the Tone X Harmonics in the project or document harmonic balance settings. (Choose Options > Default Circuit Options and click the AWR Sim tab.) This only applies when the Tone parameter is set to 1, 2, or 3 for the element. An error is issued if this parameter is set to zero for a source with Tone equal to 4 or more.

MinRes. Displays when SpecBW is "Min time res". Allows you to specify the time resolution directly on the port instead of having to use the document or project Tone X Harmonics setting.

IStart, IStop. Displays when Signal is "Sinusoid" and Sweep is "Linear", "Linear (# pts)", "Log (Dec)" or "Log (Oct)". Allows you to specify the start and stop current values in a current sweep.

IStep. Displays when Signal is "Sinusoid" and Sweep is "Linear". Allows you to specify the current step value of a current sweep.

NumPts. Displays when Signal is "Sinusoid" and Sweep is "Linear (# pts)", "Log (Dec)", or "Log (Oct)". Allows you to specify the number of points in a current sweep. When Sweep is "Log (Dec)" and "Log (Oct)", this represents the number of points per decade and octave, respectively.

Offset. Displays when Signal is "Sinusoid". Allows you to specify a DC current offset for the sinusoid that DOES NOT affect DC analysis.

WINDOW. Displays when Signal is set to anything except "Sinusoid". Allows you to specify a data window type that is applied to the source signal. Choices include "NONE", "DEFAULT", "TRIANG", "HANN", "HAMM", and "BLACK".

TIME and CURRENT. Displays when Signal is "PWL". See I_PWL for details on these parameters.

HI and LO. Displays when Signal is "Pulse", "Saw", "Square", or "Triangle". Represents the high and low current values of the signal.

TD. Displays when Signal is "Pulse", "Saw", "Square", or "Triangle". Represents the time delay of the signal.

TW. Displays when Signal is "Pulse". Represents the pulse width in time units.

TR. Displays when Signal is "Pulse" or "Square". Represents the rise time.

TF.Displays when Signal is "Pulse", "Saw", or "Square". Represents the fall time.

NOTES: Cadence® AWR ® simulators add some series resistance to this element during simulation. This may affect results if injecting current into a large resistance. To change the value of the resistance, choose Options > Default Circuit Options to display the Circuit Options dialog box, then click the AWR Sim tab and under Convergence Aids specify the Series source resistance.

If a sinusoidal nonlinear source like this one has the parameter Ang=0 and is ideally terminated, then a nonlinear measurement (for example, Pcomp or Vcomp) made at the fundamental output of that source has an angle of -90deg. This discrepancy is consistent with the definition of the sine wave sources (as in SPICE), and the Fourier-based harmonic component measurements. To avoid confusion, always measure or calculate the gain, and plot its angle.

Layout

This element does not have an assigned layout cell. You can assign artwork cells to any element. See “Assigning Artwork Cells to Layout of Schematic Elements” for details.

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