Multi-functional Packaged Antennas for Next

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Transcript Multi-functional Packaged Antennas for Next

Practice Problems
P1.17: An FM radio receiver has an input resistance of 75 Ohm. The input signal provided by a distant
transmitter is 5 µV rms, and the receiver supplies 5 V rms to an 8 Ω loudspeaker. Calculate the
power gain of the receiver.
P1.33: An amplifier has a voltage gain of 30 dB, and a current gain of 70 dB. What is the power gain in dB?
If the input resistance is 100 KΩ, what is the load resistance?
P1.63: A differential amplifier has vo (t) = A1v1(t) – A2v2(t), If A1 = 1000, and A2 = 999, determine the CMRR.
P1.17: 9.375 x 1E12
P1.33: GdB = 50, RL = 1 KΩ
P1.63: CMRR = 60 dB
Answer: -20 dB and CMRR = 114 dB
Chapter 2: The Operational Amplifier (Op Amp)
The Operational Amplifier continued
Summing Point Constraint:
This concept refers to the fact that under
negative feedback conditions:
(i) The differential input voltage will be zero in ideal
op-amps (or very close to it in non-ideal ones)
as the gain is ideally infinite
(ii) The input current will also be zero as there is no
voltage and the resistance is very high (ideally
The Operational Amplifier continued
Note here that the resistor
R2 provides the negative
feedback to the input of the
op-amp. This means that,
as the i/p voltage increases,
the negative o/p voltage
also increases, and tends to
reduce the input to the opamp by feedback, to
provide a finite gain.