Recent content by kvtb

Hi, thanks for your replies. Very interesting discussion. When I plot sin(2*pi*(-10*exp(-2t)+4t)), I get exactly what I want/expected. But... elibj123, how did you get to this: -10*exp(-2t)+4t ? When I calculate [f(x)*x]' I get something else, namely...

I'm trying to do something very simple... I'd like to have a sine function, where the frequency is controlled by a separate frequency function Something like this: g(t) = sin(2*pi*f(t)*t) Assume that f(t) = 20*exp(-2*t)+4 I would expect a sine wave that starts at 24 Hz and then...

Hi, the trig signal is a +5V pulse, duration is 2 msBTW, in mean while, I've tried to 'measure' a transfer function (as function of Vb and Vc) and tried to fit an equation on top of it. I'll post results later.

dlgoff, turin, thanks for your replies. let me try to explain the circuit in the link I've given, using another link; http://mitglied.multimania.de/raf909/rimshot.htm the three op-amps and surrounding capacitors and resistors are sine wave generators, these generate a sine wave (at three...

turin, cabraham, thanks for your replies. I think my question was perhaps not clear or incomplete: turin: The schematic is just a small part of a larger schematic to illustrate my question, that's why there's no ground. If you interested, please take a look at transistor Q65 in cell J8 of...

Hi, as mentioned in my previous thread, I'm currently busy with a 'small' project of translating an analog device (synthesizer, based on schematics) into a digital (software) version. I know 'nothing' about EE, I'm a Computer Science guy, so hopefully this question is not too easy :-) This...

@uart and The Electrician. As a non-EE I'm quite impressed by your analysis of the schematics. I'll try to perform a manual z-tranform based on the transfer functions you've supplied. Thank you.

hello uart, I'm currently using qucs (http://qucs.sourceforge.net), but I'm considering re-simulating the same circuit in GNUcap just to be sure the software is not an issue here. I indeed think that the circuit I'm simulating is the same I've posted here. Because just by looking at the...

gentlemen, your hints brought me back on the right track. it could be a lucky shot, but found that a small change to the transfer function would give a perfect fit: H(s) = \frac{s^2 + a s}{s^2 + \omega_0/Q s + \omega_0^2} a new term has been added to the numerator: a s The...

Dear berkeman, thanks for your reply, the original circuit can be found here: http://hardware.freepage.de/cgi-bin/feets/freepage_ext/339483x434877d/rewrite/raf909/rimshot.htm or here: http://www.kolumbus.fi/janne.husu/specs/909va.gif (in j9/j10)

Hi, I'm currently busy with a 'small' project of translating an analog device (synthesizer, based on schematics) into a digital counterpart. What I do is basically simulate the device using a SPICE model. Then I look at the outputs, and see if can fit some equation on it. Based on the...