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I am new to uSimmics 5.8 and am very impressed with its capabilities. Schematic entry is very intuitive.
As an exercise, I am migrating a 3-band high-Q multicoupler design from MWO linear simulator to uSimmics. The MWO design uses multiple schematics, sub-circuits, global variables, mils for units, and ran for hours to optimize.
I soon realized that to use variables, I could only use default m for units. Adding mm, for instance, after a variable name gave an “Operation expected” error message for the space between name and mm. To get around that, and to use mils as units, I declared a constant “mils” in an equation, with the value of 2.54E-05 (meters per mil). Each variable that I declared was of the form name = 1234*mils.
In MWO, each of the three bandpass filters is a separate schematic. Each pole of each filter is another schematic, with a fair amount of detail per resonator. There is an overall multicoupler schematic.
I have realized that in uSimmics, variables are local only. Every subcircuit would require its own local variables, which is not ideal for a multicoupler comprising three 12-pole bandpass filters that must all be tuned together. For this, MWO has a Global Definitions tab at the same level as a schematic. Any declaration in Global Definitions is visible to every schematic. To get around this, I am building the entire multicoupler on a single schematic sheet. uSimmics has been very responsive and completely stable. I am very impressed.
In MWO there is a simulate button and optimize button. It appears that the circuit structure determines whether an optimization is initiates. I need to learn more before I try any complex optimizations.
As I continue my exercise, I continue to be amazed. As uSimmics (QucsStudio) matures, it is becoming quite a competitor to the likes of Microwave Office. Thank you and keep up the great work!
Bill N4ES
Thanks for the praise! I’m glad that you like it.
The unit “mil” can be used after numbers like all other units, too. So, “10 mil” works, but “var1 mil” does not. Usually, I recommend to define a variable with unit, e.g. “var1=10 mil”, and not separate the number from the unit.
Indeed, there are no global variables in uSimmics. The usual way is to define subcircuit parameters instead. Please read the section “Working with Subcircuits” in the program help (F1 key) to see how this is done.
Concerning optimizations, yes, it is performed if (and only if) an optimization component is placed into the schematic. This can be disabled if it should not be used anymore. (right-click on it and choose “Deactivate/Activate”)
Good luck!
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