

Quiz 2  Communication Systems
Given the following RF circuits, ideal and nonideal amplifier parameters, calculate the solutions to the problems
presented in this communication systems course quiz.
1. Using the above values (watts) calculate the input signal to noise ratio (Si / Ni) in dB.
2. Calculate the following parameters using the given values above:
a) Find the input signal (Si) in dBm
b) Fine the input noise (Ni) in dBm
c) Using parts a and b calculations in dBm, determine the input signal to noise ratio (Si / Ni)
3. If the amplifier was an ideal amplifier, that being the noise power was equal to zero (Np = 0) determine the following:
a) Using the input signal and input noise in watts, calculate the output signal (So) and output noise (No) in watts
b) Now calculate the output signal to noise ratio in dB (So / No = ?)
c) Calculate the amp power gain (Ap) in dB
d) Using the input signal and input noise in dBm, calculate the output signal and output noise in dBm
e) Using your answer in part d, calculate the output signal to noise ratio (So / No = ?)
4. Using the non ideal amplifier configuration where the amplifier noise power is (Np = 6 x 10^{12}) find
the output noise, output signal to noise ratio, and the noise figure of the non ideal amp in decibels (dB). Note,
the Np is the noise power added by the amplifier.
Solutions:
Engineering key words: RF, radio frequency, dBm, decibel, NF, noise figure, microwave amplifier, noise power,
internal noise, resonance, signal to noise, input and output characteristics, calculation, simulation, power,
gain, amp, ideal, nonideal, comm system, watts, dB conversion, dB to dBm, specs.
