Keysight ADS rise time andfall time simulation
I am measuring the rise time and fall time each time manually whenever I am changing the values of L and C. Is there any way that I can calculate the LC values for desired rise time and fall time given a specific input signal with specific rise time and fall time.
is there any automatic way that it optimize the values of LC according to some desired RT/FT value.
I have seen optimize module of ADS but there is no option of calculating the RT/FT directly from ADS simulation.
1.
An important factor easily overlooked is input impedance. Maybe known and visible in the form of a resistor, or it may be unknown and invisible as coming through a component, IC, power source, etc.
Some amount ought to be included in calculations.
2.
By itself a series inductor slows transitions. Likewise the capacitor to ground. When both are put together they tend to introduce resonant behavior. Thus the oscillations (ringing) as shown in your scope trace. It complicates a formula.
If the incoming square wave matches the resonant frequency, then the inductor slows the leading transition. The capacitor charges and blocks current, causing output to return to zero at about the right moment to coincide with the next transition. It's a handy method to obtain sine wave output.
A circuit simulator is ideal to investigate this behavior.
You're doing a Transient simulation and no optimization can be done in such simulations.
Why because time domain response of ANY circuit has a Transient regime until the circuit settle down to continuous regime.But desired RT/RF ratio will be where ?
Therefore it's not possible to do optimization in Transient simulation.Instead, LTI system must be well settled down and this is possible with only and only Harmonic Balance/PSS techniques.
You can do a optimization in time domain within HB analysis..I don't know how to write Measurement Equations ( I have never done) but if it's possible to do, it will be only and only with HB/PSS techniues.
Really? That's surprising because optimization circuit parameters in transient simulation is e.g. well possible in PSpice. More generally, it's possible with any circuit simulator that allows batch runs and measurements in transient simulation, using an external control application.
Technically, you need to understand that the LC filter Q needs to be controlled to tune the waveform. This can be done either by utilizing a resistive source or load or a resistor in the filter.
Another approach is to refer to a known low pass filter prototype, e.g. Bessel/Gauss for no-overshoot response.
I don't know how and which time point could be used for an optimization ? For instance, let's consider that problem as a sample, how and at which time slot will be used ?
Or let's establish a similar problem. Imagine a RLC network and you would optimize C value that would give max./desired voltage across it while it's been driven a constant current.. How you can optimize ? At which point of transient regime..
I do personally not know..
You need measurements e.g. for rise time and overshoot and performance criteria related to it.