Cadence PSPICE SCHEMATIC Instrukcja Użytkownika Pobierz pdf (Strona 20)

Output

10n

Vin

1Vac

0Vdc

Vin

1Vac

0Vdc

10k

Figure 26: Filter formed by a resistor and capacitor.

• Don’t forget the ground symbol for the zero node.

The simulation settings are shown in ﬁgure 27. The Analysis type is AC Sweep/Noise. Make

sure that the AC Sweep Type is Logarithmic by Decade, which should be the default. Frequency

sweeps are almost always logarithmic because this shows low and high frequencies equally

well. Make sure that the range is suitable, based on the Bode frequency that you calculated

above. My entries may not be correct!

Put a voltage marker on Output and run the simulation. You should see a plot of the voltage

as a function of frequency, rising to 1 V at high frequency (yes, it’s a high-pass ﬁlter). The

frequency axis is logarithmic, which means that successive labels have the values 1, 10, 100. . . .

The behaviour of the circuit is clearer if the voltage axis is also logarithmic. There is a

button for this or you can choose Plot > Axis Settings. . . from the menu bar. This makes

the low-frequency part of the plot into a straight line, as in ﬁgure 28 on the following page,

Figure 27: Simulation settings for an AC sweep.

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Cadence PSPICE SCHEMATIC Instrukcja Użytkownika Strona 20