![]() ![]() My QUCS schematic source files here: qucs-schematic. So what is wrong here? Should i add 50Ohm at the end or maybe decoupling capacitors. I want to build a simple circuit with S-parameters box as a starting point for further matching. Frequency sweep range the same as in datasheet (100Mhz to 26GHz) My idea was that if i see smith chart of a raw device, it must be something like datasheet:īut it is not. So here it is:Īnd build Smith-chart for it. Actually it is modified last example of line matching to 300 Ohm at **broken link removed** tutorial. So i decided stop searching for spice equivalent scheme of NE3210S01 and use simple S-parameters file NE3210S01v1_2-18_2_10.S2P.Īfter adding two-port S-parameters box to QUCS i found some unknown Vref voltage pin, and connected it to ground. 5, is needed at a later stage of the Verilog-A model development process. In the case of the RnonLin model this is held in le RnonLin:dat 2. But i read somewhere that S-parameter files can be successfully used for many simulations, representing device as a "black box" with known input and output. Saving the model symbol causes Qucs to automatically generate the C++ code for the new symbol. Fortunately i've found this tutorial: **broken link removed** (A Qucs Tutorial for RF Transmission Lines) Very good tutorial.Īlso i found information about using SPICE model of some transistor in QUCS: reports/14.Bah-Transistor_simulating_report.pdf. QUCS is very good program, although it is not so obvious how things can be done because need to add some equations. NE3210S01v1_2-18_2_10.S2P - ! Vds = 2 V Id = 10 mA <- (i think need use this file, looks like typical safe biased operation). NE3210S01v1_2-18_0_-2p5.S2P - Vds = 0 V Vgs = -2.5 V (device is turned off, but some negative DC bias on gate?) My first confusion is why there are three sets of S-parameters? I downloaded S-parameters files for NE3210S01 from this webpage: Models are provided by device makers, distributors or web sites like this one. Indeed device models have to be added manually to the devices in the circuit schematic, when invoking ngspice via KiCad or QUCS-S, except for some basic devices with integrated models. Many of these xes are now included in the latest CVS code and will eventually form part of the next Qucs release. ![]() Go to examples Examples For an easy start have a look at the QucsStudio example projects. release of Qucs 0.0.8 there has been considerable activity centred around nding and correcting a number of bugs in the Qucs digital simulation code. View Examples For an easy start have a look at the QucsStudio example projects. A growing community is supporting digital, analog or mixed-signal design flows. Screenshots Get a first impression about QucsStudios feature set in our screenshot and video galery. Device models are available by the Open Source PDKs from Google/Skywater, Google/GF, or IHP. KiCad integrates ngspice internally, but may also provide external ngspice with netlists for simulation.Īnother GUI to ngspice is XSCHEM, especially useful for IC design work (see ). You may watch several simulation examples (including oscillators) here. KiCad may be used as a schematic entry tool for ngspice, especially for discrete or PCB-based electronics. When talking about open source tools, here are some: AD and Qorvo aren't remotely in the software and EDA business, so their decision to keep them closed is even more puzzling, but I guess the instinct of hardware companies is guard everything. LTspice is kind of an advertisement for AD's chips. QucsStudio was taken closed-source by Qucs' original author, and he's not commented on his intentions in this decision.īig companies typically open-source software when it's not part of their strategic business value, and offers community engagement benefits and good press. The recently-released QSpice (sponsored by Qorvo) also closed-source. LTspice (sponsored by Analog Devices) is closed-source. SPICE predates copyleft licensing, so software that was once open has disappeared into proprietary versions. It's nice that there are several free-as-in-beer options available, but a good lesson in the consequences of permissive open-source licenses. ![]() It's a shame that circuit simulators, especially those derived from SPICE, have tended toward closed-source. ![]()
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