Fig. 5.55.a: Ten-stage crystal band-pass filter
Apart from time-domain simulation, Alecsis simulator also performs the frequency domain simulation. Following examples illustrate this feature.
Implementation of the frequency domain simulation implies extensions of the AleC++ language. Command ac specifies frequency domain simulation. Independent sources vac (voltage) and cac (current) provide excitation. Since AleC++ is extension of the C++, values are treated as objects. In this manner, for frequency domain simulation, they have been added new properties: amp (amplitude), phase (phase), real (real part) and imag (imaginary part), with output->phase specifying the phase of the output .
As a simulation example for passive circuits, a ten stage crystal band-pass filter shown in figure 5.55.a has been simulated. Obtained amplitude characteristic is shown in figure 5.55.b.
As an example for simulation of active circuits, a simple one-stage MOS amplifier has been simulated. Figure 5.56.b shows the simulation results for variations of the supply voltage.
Fig. 5.55.a: Ten-stage crystal band-pass filter
Fig. 5.55.b: Amplitude characteristic
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Fig. 5.56.a: Simple MOS amplifier |
Fig. 5.56.b: Amplitude characteristic for supply variation |
vac Vin;
mosfet m1;
Vin(input1, 0) {amp=1mV; phase=0rad;};
m1(d, g, s, 0) {model=my_nmos; l=2u; w=6u; };...
plot{node d->amp;}
ac {fscale = 2; fstart = 1; fstop = 100G; fnum = 100;}