6.1. Simulating the IF filter in LTSpice In this part of the homework, you will simulate the IF filter of the NorCal40A radio using LTSpice. The filter architecture is given

below. 750.1 pF HOHOH 750.1 pF 790 pF HOHT 丰 Q1. Draw the equivalent circuit diagram, as simplified as possible, and explain how this works as a band-pass filter. Q2. Simulate the filter from 4-6 MHz using a 50 2 impedance at the output (scope) and a 50 2 generator at the input. Note that the crystals are modeled by a series RLC circuit in parallel with a capacitor Cp (Fig. 5.13 in your textbook) with the following parameters: L-20 mH, C-52.5 fF, R=5 2 and Cp 100 pF. (Do not simulate the simplified ladder circuit from the previous question.) Attach a plot of the output across the frequency range 4-6 MHz. Q3. What is the simulated pass-band bandwidth and the frequency at which the filter has minimal loss? Pass-band bandwidth: Frequency of minimum loss: Q4. How does the filter response change if the capacitors that are connected to the generator and scope change from 750.1 pF to 400 pF and the capacitors to ground change from 790 pF to 460 pF? Attach a plot if helpful. Q5. Change the capacitors back to their original values. How does the filter response change if the frequency of the edge crystals increases by 5% and the frequency of the middle crystals decreases by 5%? Attach a plot if helpful.