In this lab, we will finish the RLC band-pass filter on page 2 of Lab 6 and plot results with the Matlab script lab7.m. Additional instructions will be given in the lab session, but the main objective is to plot the gain versus frequency (analytical and measured) for several inductor values. We will study the "frequency response" more thoroughly in ELEC 226, 320, and 350.

Please go through the following steps during lab. We will use only the 10 mH inductor in the RLC circuit.

1. Measure the DC resistance, r, of the 10 mH inductor (using the ohmmeter).
2. Use the Matlab script to plot the analytical frequency response (amplitude gain versus frequency) of the RLC circuit. Plot the frequency response with r=0 and with your measured value.
   • What is the advantage of displaying the gain in dB on a Bode plot?
   • Try changing the semilogx to plot to use a linear scale along the frequency axis. What is the advantage of the logarithmic frequency scale?
3. Simulate the RLC circuit in PSpice and plot the output voltage versus frequency, with r=0 and with your measured value. Do the PSpice results agree with the Matlab plots? Try to display the PSpice amplitude gain in dB.
4. Build the RLC circuit with 10 mH inductor and measure the input and output voltage amplitudes at about 10 different frequencies.
   • Explain the variation in input voltage amplitude in terms of the Thevenin equivalent circuit of the source.
   • Enter your measured frequencies and amplitudes into the Matlab script and compare the measured gain with the analytical gain. Do they match? Is it necessary to include the inductor resistance (r) to get a good match?
   • Measure the resonant frequency of your circuit and compare with the analytical value and the PSpice result.
5. Derive the analytical frequency response for the low-pass and high-pass RC circuits in Figure 1 of Lab 6. Develop Matlab scripts to plot the frequency response for each circuit.
6. Derive the analytical frequency response for the practical differentiator in Figure 6 of Lab 4, then develop a Matlab script to plot the frequency response. Compare with the frequency response of the ideal differentiator in Figure 4. Over what frequency range does the practical differentiator behave like the ideal differentiator? Over what frequency range does the practical differentiator behave like an inverting amplifier?

No lab report is required, but please discuss your results with the lab instructors. You do not have to print the plots, but show them on the monitor as you discuss the results. Thank you.