Sawtooth wave generation

Help
Cousteau
2011-11-23
2012-12-15
  • Cousteau
    Cousteau
    2011-11-23

    Hi. I'm trying to get a sawtooth waveform generator, which doesn't seem to exist in Qucs (at least in 0.0.15).
    I've tried to achieve this by creating an equation that defines tri=time%1, and then putting a voltage source of value tri, but a transient simulation shows that the source has a constant 0 V. However the value of tri varies according to the formula, giving a pretty sawtooth shape (which apparently I cannot use).
    Right now I'm experimenting with a square wave and an integrator, which gives me a triangular wave (symmetric or asymmetric)… Any idea of how could I get a sawtooth waveform generator?

    PS: I have previously posted a topic to the forum but has been marked as spam (maybe because of the imageshack pic I used?)

     
  • brassneck
    brassneck
    2011-11-27

    Hi cousteau

    I'm not sure if I can help, but I posted a question over a year ago about using the simulation time variable in simulations. If I understand your post correctly, it looks like you're using the time variable to generate the sawtooth.

    Could you paste the file, or provide a link, so that I can look at what you've done? Maybe we can help each other.

    Thanks

    Brian

     
  • HomuZorow
    HomuZorow
    2012-01-11

    Hi cousteau

    Why don't you use "Rectangle Voltage source" ?
    For example, set the values as follwings:
    TH=1ms
    TL=1ns
    Tr=1ms
    Tf=1ns.

    Thanks

     
  • Cousteau
    Cousteau
    2012-01-13

    homuzo:  Thanks!  I didn't think of using the rise and fall times for converting a square wave on a triangular one.  Good idea!