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A Unified SPICE Compatible Model for Large and Small Signal Envelope Simulation of Linear Circuits Excited by Modulated Signals . Simon Lineykin and Sam Ben-Yaakov*
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A Unified SPICE Compatible Model for Large and Small Signal Envelope Simulation of Linear Circuits Excited by Modulated Signals Simon Lineykin and Sam Ben-Yaakov* Power Electronics LaboratoryDepartment of Electrical and Computer EngineeringBen-Gurion University of the NegevP. O. Box 653, Beer-Sheva 84105, ISRAEL Phone: +972-8-646-1561, Fax: +972-8-647-2949Email: sby@ee.bgu.ac.il, Website: www.ee.bgu.ac.il/~pel
A Primer to Envelope Simulation • Any analog modulated signal (AM, FM or PM) can be described by the following expression: • The Current in the network excited by u(t):
Phasor Analysis • Inductance
Phasor Analysis Capacitance Resistance
Splitting the Network into Two Cross-Coupled Components - Imaginary and Real
Real Load Component Imaginary Load Component Splitting the Network into Two Cross-Coupled Components - Imaginary and Real
Simulation Alternatives • Cycle-by-cycle (full simulation) • High and low frequencies • Very long simulation • Only transient • AC transfer function -> point-by-point • Envelope simulation (Large Signal -Previous study) • Only low frequency • Only transient • AC transfer function -> point-by-point
Example: Piezoelectric Transformer Driven by FM Signal (SPICE)
Example: Piezoelectric Transformer Driven by FM Signal (SPICE)
Example: Piezoelectric Transformer Driven by FM Signal (SPICE)
Example: Piezoelectric Transformer Driven by FM Signal (SPICE) - Harmonic modulating signal
Example: Piezoelectric Transformer Driven by FM Signal (SPICE)
OrCAD Schematics for Envelope Simulation (Large Signal)
Results of Full and Envelope Transient Simulations The modulating input signal Envelope The Frequency modulated signal Cycle-by-cycle Envelope Cycle-by-cycle Output signal
Objectives of this Study • To extend the envelope simulation method to AC analysis • A method that would not need an analytical derivation • Same model compatible with DC, AC, and Transient analysis types
Proposed Method – Small Signal Analysis Using AC–Simulation • Amplitude modulation phasor The source is linear and suitable for AC analysis – as is
=Ac Small signal =Ac*kp*u(t) Small signal Linear source Linearization of Sources for Angle Modulation • Phase Modulation phasor PM – Nonlinear source
=Ac Small signal =Ac*kp*u(t)dt Small signal Linear source Linearization of Sources for Angle Modulation • Frequency Modulation phasor FM – Nonlinear source
Results: Piezoelectric Transformer Driven by FM signal (AC and Point-by-Point) for Different Carrier Frequencies
Results: Piezoelectric Transformer Driven by FM signal (AC and Point-by-Point) for Different Carrier Frequencies
Frequency Response of the Network (unmodulated input signal) using DC-sweep • DC-sweep in envelope simulation is equivalent to frequency sweep in full simulation • The parameter of DC sweep is a carrier frequency fc • The source for DC sweep:
Example: Frequency Response of Piezoelectric Transformer with Different Resistive Loads
Conclusions • Envelope simulation method was extended to cover all simulation types: Transient, AC, DC. • Method is suitable for any linear circuit. • Method is also suitable for nonlinear circuits that can be linearized for small signal.