Problem 1:

The tuner for an FM radio requires an RLC series resonance band-pass filter with a resonance (central) frequency of 100 MHz (frequency of the FM station) and a bandwidth of 2 MHz. The aim here is to design a filter capable of passing the signals from the FM broadcast radio while rejecting the interfering signals from amateur radios and Military aircraft radios. The usual frequency bands reserved for the use of amateur radio is around 50 MHz and the frequency bands reserved for the use of Military aircraft radio is around 200 MHz.

a.) Calculate the:

i. magnification factor Q of the filter

ii. required value of inductance L

iii. required value of capacitance C

iv. required value of resistance R

v. cut-off frequencies

vi. Prove that the interfering signal originated from amateur radio at 50 MHz is reduced by at least 95%.

vii. Prove that the interfering signal originated from military aircraft radio at 200 MHz is reduced by at least 95%.

b.) Use Multisim to simulate your design and provide the complete circuit diagram of the filter (Please use screenshot).

c.) Provide the gain magnitude plot of your filter at the resonance frequency, the cut-off frequencies, the amateur radio frequency of 50 MHz, and the military aircraft radio frequency of 200 MHz. (Please use screenshot).

Problem 2:

Assuming that you have an ac power source of 10V (60Hz). Design a silicon based filtered full-wave bridge rectifier circuit that gives dc voltage output Vdc, varying at most ±5%. (If required use first diode approximation in your calculations.)

a.) Calculate the required value of resistance R b.) Calculate the required value of capacitance C

c.) Provide the complete circuit diagram of the rectifier circuit (including the values of R and C)

d.) Use Multisim to simulate the waveforms at the:

i. input and output of the transformer (use colour coding and labels),

ii. input and output of the rectifier (use colour coding and labels), for confirming that the requirements have been met

iii. Measure the average output dc voltage by using a multimeter. (Please use screenshot).

Problem 3:

Assume that you are working in America at a company that designs, tests, manufactures and markets various electronic instruments including dc power supply. The standard line voltage and frequency in America is 120V and 60 Hz, respectively. Your first assignment is to design an electrically isolated filtered Silicon based power supply that can produce dc output voltages of 9V±10% and -9V±10% with a maximum load current of 100mA. The voltages are to be switch selectable across one set of output terminals and the ripple voltage must not exceed 0.25V rms. Please use second diode approximation in your calculations.

a.) Calculate the:

i. required value of the load resistance RL
ii. required value of the capacitor C in order to fulfil the requirements of the circuit.

b.) Provide the complete circuit diagram of your design including the values of the each component, explain and justify your reasoning regarding your circuit design and values of the components used.

NB: You will need to use the mains as an input to your power supply and a transformer with one input and one output to the full-wave bridge rectifier. It is also preferable to use a surge resistance of 1Ω at the unfiltered output of the circuit in order to prevent too much current flow through the circuit. In order to simplify your calculations please neglect the effect of the 1Ω surge resistance.