1. Your company have been asked to design an attenuator which interfaces between a television receiver and a high gain aerial. Unfortunately the aerial has been designed incorrectly with the right gain, but the wrong characteristic impedance.
Through experimentation with an asymmetric attenuator using a 0 - 0.75K? potentiometer set to 43% and a variable resistor set to 136.8? (shown below), the required attenuation was achieved (AC is connected to the aerial, BD is connected to the receiver).
a. Determine the image impedance seen at AC
b. Determine the image impedance seen at BD
c. Assuming the receiver is impedance matched with that seen at AC and is connected across BD with AC as the input; determine the insertion loss and attenuation.
d. The aerial will be re-designed to have the same impedance as the receiver.Design a fixed single stage symmetrical attenuator to provide the same amount of attenuation.
e. Verify the attenuation of your symmetrical design matches that of the asymmetric experiment by constructing and analysing the attenuators on Multisim (or something similar).
2. It has been measured that the voltage supplied is:
v = 325.27sin(ωt) + 128.42sin(3ωt + 65°) + 77.22sin(5ωt - 30°) Volts
when connected to the circuit shown below.
Assuming the frequency is 50Hz, and the capacitor C is tuned to produce resonance at the third harmonic, determine:
a. The value of the capacitor
b. An expression for the currentsupplied to the circuit in the Fourier form
c. The RMS value of the voltage and current supplied
d. Using the applications package Multisim (or something similar), construct the circuit and explain how your simulation matches the voltage specified.
e. Using the instruments available in the simulation package (e.g. a multimeter set to AC Volts), estimate the RMS voltage and current for the circuit and compare it to the values determined in part c.