Activity for Buenos
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Buenos modified a comment on discussion Open Discussion
The component (connectors, chips) vendors provide their models with 2k-8k samples. I have no way of resampling them before inserting htem into QUCS. So the software has to support existing model files we obtain on the market.
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The component vendors provide their models with 2k-8k samples. I have no way of resampling them before inserting htem into QUCS. So the software has to support existing model files we obtain on the market.
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If I try to import anything larger than maybe 60MBytes S-parameter file, the simulator crashes with an error. For professional simulations in digital electronics, we need to chain together multiple S-par files that are 32 ports each, having maybe 4000 samples, that is more than 500MBytes. If we insert 4 Spar files, each being 600MBytes, that is 2.4GBytes. Typical error message: line 500880: memory exhausted checker error, found 6 options checker error, option s' occurred 2x checker error, options'...
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Hello. Normally we would run TDR si sims on S-parameter models. That would require a convolution-based transient solver, that QUCS does not have. I tried to run an S-par sim, then use formulas to produce a TDR plot, but I think I have some bugs in my calculations. If you can make formulas correctly, including FFT, then you might be able to do TDR in QUCS, in S-par sim model, not in transient sim. This is my template that includes TDR computation from Spar: https://www.buenos.extra.hu/download/Ch...
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Hello. Normally we would run TDR si sims on S-parameter models. That would require a convolution-based transient solver, that QUCS does not have. I tried to run an S-par sim, then use formulas to produce a TDR plot, but I think I have some bugs in my calculations. If you can make formulas correctly, including FFT, then you might be able to do TDR in QUCS, in S-par sim model, not in transient sim.
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"see the thread above." Above where? I have the same problem, cannot simulate with 36port Spar models.
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I have noticed that the FEXT crosstalk seems to be proportional to the rise time in the simulation results. If we look at a FEXT s-parameter curve in another simulator, we can notice that FEXT linearly increases with the knee frequency (f=0.35/trise), but only up to fmax=0.5/t_pd. bove that it goes up and down periodically, and lingers around -60...-20dB. On a 5" trace that limit is 0.5GHz. TNT MMTL still gives me linearly increasing FEXT as I keep changing the rise time parameter in the range of...
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This doesnt work, even though the documentation lists it as an existing feature: M[:,3] Vector consisting of 3rd column of matrix M checker error, no appropriate function for `M[range('?','?'),3]' found
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If I expand my vector into a matrix like this m3=[zaza;nh] where nh is a 39x40 matrix of zeroes, then I am able to multiply it by a matrix like the identity matrix or my reversal matrix like m4=m3*ID. But then I need to get a vector from the resulting matrix. The online manual claims that I can get a row or a column out of a matrix like this m5=m4[1,:] , but then I get an error. I am using the released 0.19 windows binary. So, several existing features dont work: - matrix by vector multiplication...
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MAtrix multiplication syntax issue
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This was resolved with ASCO support. 1. None of the equation blocks can contain more than 4000 characters. This might be problematic for manually entering large matrices, or vector reversal. Split the thing into multiple equation blocks. 2. ASCO.exe needed an code update. It might not be released yet.
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I can reverse about 200 elements like this without freezing: v2=[v1[5],v1[4],v1[3],v1[2],v1[1],v1[0],] If I do 7 of these then the simulation takes 5minutes. An optimizer simulation takes over 24 hours. I also tried to create a reversal matrix like this, that is a 90degree rotated identity matrix: rev=[0,0,1;0,1,0;1,0,0] at the size of 40x40. Then r5=[rev*r[160:199],revr[120:159],revr[80:119],revr[40:79],revr[0:39]] returns a simulation error "no appropriate function found..."
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I can reverse about 200 elements like this without freezing: v2=[v1[5],v1[4],v1[3],v1[2],v1[1],v1[0],] If I do 7 of these then the simulation takes 5minutes. An optimizer simulation takes over 24 hours. I also tried to create a rotation matrix like this: rot=[0,0,1;0,1,0;1,0,0] at the size of 40x40. Then r5=[rev*r[160:199],revr[120:159],revr[80:119],revr[40:79],revr[0:39]] returns a simulation error "no appropriate function found..."
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Vector reversal function
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FFT should have correct independent variable
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Update: I have implemented the lossy diff TLINE using Eq controlled RF device. This works well, although it is hard to add one more instance to the same schematic, as it would require the user to rewrite 16 very long equations. My template has 4 instances in it. http://buenos.extra.hu/download/Channelsim_template_prj.zip It would be nice to have a hard component implementing it.
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Optimizer crashes with error referencing source code
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If it is a global parameter, then teh equation inside a subcircuit should be able to use "F". But it cannot, it complains with error that F is unrecognized. So the same RF part can take "F" in its equation when the part is on the top level sch, but when i place it inside a subckt it throws a simulation error. I tried 2 ways: a) use it as "F" inside the subckt. b) use "FREQUENCY" variable inside the subckt and make it a parameter that is assigned F on the top level. Both ways it failed to simulate....
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I created a modified version of this that demonstrates the bugs. the subcircuit models inability to take freq, and the tline models inability to take equations or freq dependent equations. buenos.extra.hu/download/tline-errors-demo.zip updated file on ftp at 2021-07-09-2:18pm
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If it is a global parameter, then teh equation inside a subcircuit should be able to use "F". But it cannot, it complains with error that F is unrecognized. So the same RF part can take "F" in its equation when the part is on the top level sch, but when i place it inside a subckt it throws a simulation error. I tried 2 ways: a) use it as "F" inside the subckt. b) use "FREQUENCY" variable inside the subckt and make it a parameter that is assigned F on the top level. Both ways it failed to simulate....
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If it is a global parameter, then teh equation inside a subcircuit should be able to use "F". But it cannot, it complains with error that F is unrecognized. I tried 2 ways: a) use it as "F" inside the subckt. b) use "FREQUENCY" variable inside the subckt and make it a parameter that is assigned F on the top level. Both ways it failed to simulate. Last night I spent few hours in developing a third way: use the equ defined RF component to implement both the freq dependent loss and the TLINE delay,...
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I created a modified version of this that demonstrates the bugs. the subcircuit models inability to take freq, and the tline models inability to take equations or freq dependent equations. buenos.extra.hu/download/tline-errors-demo.zip
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Please release V20 windows binary with the features already there
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Update: I was able to model lossy TLINES, by connecting a diff tline with zero loss, in series with an equation controlled RF device that creates the freq dependent loss. This has 2 issues: 1. This combo cannot be placed into a QUCS subcircuit, because QUCS refuses to pass the frequency parameter into the subcircuit and throws an error. 2. Leaving the combo on the top level schematic makes it hard to manage when trying to add more tlines to or to change the structure to match an actual design. Here...
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I'm having the same issue. It only works when I have one instance of the subcircuit in the main schematics page, while it crashes when I have 2,3,4 or more instances. I need several instances, it can even go up to 24 instances in some cases, but 4 is minimum for my design, each with different parameter values.
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I'm having the same issue. It only works when I have one instance of the subcircuit in the main schematics page, while it crashes when I have 2,3,4 or more instances. I need several instances, it can even go up to 24 instances in some cases, but 4 is minimum for my design.
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How to model frequency dependent losses of a coupled transmission line? I cannot use the microstrip Tlines because by design has striplines, so I have to use the "coupled transmission line" symbol. But that one has loss related parameters as Ao and Ae. If I type in "20 dB" then the S-parameter simulation completes fine, but the line loss is 20dB at all frequencies. On a real tline the loss gets stronger over frequency. I tried to use equation to create the loss(f) function, but the Tline symbol refuses...
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I could almost use the "coupled transmission lines", but I have to feed a function into its Ao and Ae parameters, to make the loss frequency dependent. But then it does not simulate anything, the S-parameter simulation results are "nan / nan" in list view, and displays negative infinity line on graph. If I type in "20 dB" to Ao then it works, but I need it to vary over frequency, so it has to work with a function. I tried with the following equations: Ao= LOSSFACT for the tline parameter Equations:...
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Actually, you don't need to make the loss tangent (DF, dissipation factor) itself frequency dependent, even Keysight ADS does not do it, I think. If DF is a constant, even then the insertion loss profile (S21) of the transmission line will still be declining over frequency, which is what a real Tline looks like. That is what I need, but on differential (coupled) and stripline (not microstrip). http://d2xunoxnk3vwmv.cloudfront.net/uploads/loss-tangent-loss.jpg
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Need lossy stripline diffpair transmission line
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Display bugs and undo crash
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