#Qucs simulation tutorial windows#

2ģ 2 Frequency Response of a Simple Transmission Line Circuit The frequency response gives a lot of insight into a circuit s behavior. If we simulate this design, we will see that a 1 m line introduces a 5 ns delay, as corresponds to a propagation velocity of 0.66c. The equivalent length is inserted into the length property of the transmission line component. For instance, to model a lossless RG-58 coaxial line, we need a velocity factor of To achieve this, we may insert an equation item into our schematic sheet and add some equations to it: Now, if we wanted to change the physical length of the line, we would change truel. While there are other kinds of transmission line in Qucs, we will try to include an arbitrary propagation factor. It follows that Qucs is assuming that the transmission line uses air as the dielectric. After the box is inserted, we may navigate the waveform with the cursors to locate the time instant when the step is detected at the output t = Since the line length is 1 m, it follows that the propagation velocity along the line is V p = 1/ = m/s.

If everything worked ok, we should see something like: The marker on the graph is inserted with or through the insert menu. Suffix V means voltage and suffix t means time-domain data. The prefix of these signals corresponds to the node name. 1Ģ We will select the traces named V1.Vt and V2.Vt. In any case, we get an empty results page where we will insert a Cartesian plot from the diagrams palette. The simulation is started with or through the menu. These will be named V1 and V2, corresponding to the input and output port of the transmission line, respectively. Finally, we will attach markers to the nodes that we will like to watch. The most important point is the final time and the time step or, as in the figure, the number of time points where the response will be computed. In this case, a transient simulation with the parameters adjusted as shown. When setting the line length do not write m for the unit of length, as m is considered mili! After placing the load resistor, we only have to insert a simulation.

We choose the generic transmission line component for the transmission line. Hence, we have set the pulse width to 1 ms, which is several orders of magnitude longer than our simulation will last. In this case, we want to investigate the response to a step function. Next, adjust the parameters of the source as depicted in the figure. This will be our first circuit, which will be built step by step: To start, go to the sources tab and select a Voltage Pulse source.

#Qucs simulation tutorial windows#

The windows qucs runs the tutorial completely with the results showing up in the 'Tabular’ as is shown in the tutorial.Īnyone have an idea of what’s wrong with linux compiled qucs-s 0.23 in displaying results.1 A Qucs Tutorial for RF Transmission Lines Pere Palà-Schönwälder February Simple Transmission Line in the Time Domain Let s start with a simple circuit composed of a voltage generator, a transmission line and a load. I have also set up qucs 0.19 – windows version into wine on my linux pc. That again solved the schematic but displayed no results giving the same dialogue as above. If I enter a name such as “divider” and click that to the right side, it still has no value associated with “divider” voltage.Īdditionally, I tried the qucs 0…23 AppImage package. Post simulation dialogue says:Ĭircuit: * qucs 0.0.23 /home/tom/.qucs/examples_prj/dc-1.schīut on the results page, after selecing “Tabular”, a table opens but there are no results shown for selection as is presented in the tutorial. In setting up the initial tutorial schematic (voltage divider), all goes well. I have compiled qucs-s 0.23 on opensuse leap 15.3. If there are any qucs (electrical circuit analyzer) experts viewing, here is my problem.