Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
The ADS OscPort model for HB analysis is based on the Nyquist stability test critetion, which is described in "Microwave Transistor Amplifiers, Analysis and Design, 2nd Ed, G. Gonzalez", chapter 5, section 2. The idea is measuring the close-loop gain and phase to determine the oscillating condition and frequency.
The following is my opinion about OscPort usage, please comment
For a low frequency osc, the feedback path is clear. The Oscport should be inserted in the circuit in the feedback path pointed in the direction of the oscillator's gain. For example, in a common emitter/source osc circuit, the OscPort should be put in series with the base/gate of the transistor and pointing toward the transistor.
For a microwave osc, the feedback might be achieved by parasitic parameters of the transistors. The osc could be treated as a two port negative resistance model (see Gonzalez book ch5.3). The OscPort should be put between the transistor and the resonant network. Its direction does not really matter, based on my experiment, there is no difference in simulation results and time.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
