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1st post, and I’m new to Qucs studio (long term user of ADS and MWOffice).
I’m trying to setup the optimiser to optimise a filter. I need equations as I understand it , to define the goals. Being a filter I have S(2,1) and S(1,1) goals in-band and S(2,1) goals out of band.
The syntax for evaluating the goals over a specific range of the sweep frequencies is not discussed in the documentation, but there are several examples online of users setting up such goals. But, having borrowed some of their equations, I get an error:
Error in ‘Eqn1’: Operation expected in equation “max(dB(S[2,1]),4500e6:4600e6)”.
How am I meant to do this correctly – maybe there is a blindingly obvious typo I can’t see through, or perhaps the method has become deprecated etc. Surely there is a right way to do this sort of thing?
Many thanks for any guidance.
Seems that max() does not support a range selection.
max(range(dB(S[2,1]),45e6,60e6))
seems to work.
Thank-you – that seems to work OK, and it shows a different way of working the ranges from examples online.
I have a functioning optimiser now.
Perhaps the documentation could be clear about this very common requirement?
Happy to hear that.
You mean there is a QucsStudio example that is not working?
>Perhaps the documentation could be clear about this very common requirement?
What improvement do you suggest?
The F1 help page “Mathematical Functions” gives the definitions
max(x) – maximum of all values in xs
range(f,x1,x2) – y values of f whose x values lie between x1 and x2It should be clear, that max() has only one parameter.
To be clear, the examples are from other posts online, not official examples.
I think its a mistake to assume that because documentation is complete that it is adequate.
It would assist users to discuss this common task in the section on the optimiser rather then them have to find it in a long list of other functions and have to realise its relevance. I would expect most users want to restrict the frequency range of their goals. The way QUCS Studio does this is different to ADS and other similar packages, so a helping hand may be in order.
Another issue with the optimiser in QUCS Studio is that it conducts its business in private. ADS and MWO both show the intermediate steps which can help to understand how to hone the goals to get what the designer wants. The optimiser can also be interrupted and variables tuned or their range restricted if the optimiser wanders off into the weeds.
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