This file contains a number of SDD (Symbolically-Defined Device) examples.
These devices allow users to quickly, easily and reliably add custom
nonlinear models to the circuit and RF system simulator in the
Advanced Design System.
* Users define port voltages and currents as functions of other voltages and currents.
* No C-coding or compilation is required.
* Derivatives are generated automatically by the simulator.
SDD_cap is a simple, voltage-dependent capacitor model.
SDD_cap2 is a similar voltage-dependent capacitor model, that behaves identically.
Test_SDD_cap simulates the capacitance versus bias voltage.
* No need to learn how to "load the matrix".
* One set of equations is used for all analysis types, including DC, AC, S-parameter, harmonic balance, and Circuit Envelope.
Cubic is a simple, third-order nonlinear "resistor" implemented with an SDD. The I-V curve as well as the current spectrum and time-domain waveform are simulated.
SDD_Diode is a diode modeled with an SDD. This model can be used to model a varactor diode, also.
TestDiode simulates the bias-dependent capacitance of the SDD_Diode.
selfHeatingDiode.dsn shows how to include a diode's self-heating in its model.
Test_selfHeatingDiode.dsn performs a DC simulation to get the I-V curve which includes the effect of the junction temperature.
NonlinearAmp is an ideal amplifier modeled with a two-port SDD. The user can set input and output resistances, small-signal gain, and saturated output voltage.
TestAmp simulates the DC input-output voltage characteristic as well as the compression characteristic of the NonlinearAmp.
IdealMixer simulates an ideal mixer (really a voltage multiplier) with a three port SDD.
RemCC is an example of a controlling current used in an SDD. The voltage at the output of an SDD is a function of the current in a voltage source. A voltage is generated that is equal to the instantaneous power dissipated in a resistor.
Sine simulates an SDD implementation of an ideal VCO. An FM signal is applied to the control voltage input, and the time-domain signal and spectrum are plotted.
VCObd is a block diagram of a VCO, but it is not simulated.
WeightLPF is an example that shows how to define several weighting functions. These functions allow the user to define equations with derivatives and more complicated expressions.
RecConv shows a pulse driving a low-pass filter, implemented via a polynomial. Recursive convolution, which handles frequency responses with polynomials more efficiently in the time domain, is used in the simulation.
GumPoon implements a Gummel-Poon BJT model via an SDD.
GumPoon_DCtest simulates the DC I-V curves of the device.
GilCellMix is a Gilbert cell mixer implemented with the SDD Gummel-Poon model (although the biasing resistors have not been optimized so the mixer does not have good conversion gain.)
MixHBTest is a simple harmonic balance simulation of the Gilbert cell mixer.
SDD_cap is a simple, voltage-dependent capacitor model. SDD_cap2 is a similar voltage-dependent capacitor model, that behaves identically. Test_SDD_cap simulates the capacitance versus bias voltage.