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In this tutorial, you will
The EWB bode plotter is useful in checking the frequency response of filters. Figure 19-1 shows the bode plotter icon connected to an RC low-pass filter. The bode plotter requires that an ac source be set at an arbitrary frequency and amplitude be connected to the circuit input. The filter input is connected to the IN terminal and the filter output is connected to the OUT terminal of the bode plotter. The two common terminals are connected to ground, as shown.  Figure 19-1 The EWB bode plotter connected to an RC low-pass filter like the one in textbook Figure 19-5. Example 19-1 Solution The magnitude response curve is displayed on the expanded bode plotter in Figure 19-2 on a logarithmic scale. To measure the critical frequency, move the vertical cursor from the left side of the screen to a point where the dB reading is as close to –3 dB as possible. The approximate critical frequency is read as 32.359 kHz in this case.  Figure 19-2 Simulation Connect the filter in Figure 19-1 and measure the critical frequency. Example 19-2  Figure 19-3 Solution The bode plotter in Figure 19-4 shows the cursor positioned at –2.923 dB, which is as close to –3 dB as the simulation allows in this case. The critical frequency displayed by the bode plotter is 10.471 kHz.  Figure 19-4 Simulation Connect the high-pass filter in Figure 19-3 and measure the critical frequency. Example 19-3  Figure 19-5 Solution The bode plotter in Figure 19-6 shows the response curve and the cursor indicates a center frequency of 7.943 kHz.  Figure 19-6 Simulation Connect the bandpass filter in Figure 19-5 and measure the critical frequency. EWB MultiSIM Exercises
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