GROL Amplifier and Oscillator Circuits 4

Question 1

Neutralization of an RF amplifier stage is performed to:

Accepted Answer

Cancel unwanted feedback caused by the transistor's internal collector-base capacitance

Answer

Increase the amplifier's output power level

Answer

Reduce the noise figure of the amplifier

Answer

Improve the DC bias stability of the stage

Question 2

The 3 dB bandwidth of a single-tuned RF amplifier stage is determined by:

Accepted Answer

The ratio of resonant frequency to the circuit Q factor

Answer

The transistor's current gain and supply voltage

Answer

The total capacitance in the tuned circuit alone

Answer

The number of turns on the interstage RF transformer

Question 3

Intermodulation distortion (IMD) products are generated when:

Accepted Answer

Two or more signals pass through a nonlinear device, producing spurious sum and difference frequencies

Answer

A single signal is amplified in a perfectly linear amplifier

Answer

The output stage is driven to its supply rail voltage

Answer

An amplifier is biased in Class A mode

Question 4

Automatic Gain Control (AGC) in a communications receiver is used to:

Accepted Answer

Keep the receiver's audio output relatively constant despite varying received signal strength

Answer

Increase the transmitter power output during weak signal conditions

Answer

Switch between AM and FM demodulation automatically

Answer

Prevent overloading of the antenna tuner

Question 5

Why is the noise figure of a receiver's first RF amplifier stage especially critical?

Accepted Answer

Noise introduced in the first stage is amplified by all subsequent stages, directly limiting receiver sensitivity

Answer

It determines the maximum output power of the entire receiver

Answer

It sets the receiver's operating frequency range

Answer

It determines the selectivity of the IF filter

Question 6

The dynamic range of a receiver is defined as the difference between:

Accepted Answer

The strongest signal that can be received without distortion and the weakest detectable signal (noise floor)

Answer

The maximum and minimum allowable supply voltages

Answer

The highest and lowest frequencies the receiver can tune

Answer

The input and output impedances of the receiver

Question 7

A cascode amplifier configuration uses two transistors to primarily:

Accepted Answer

Reduce the Miller effect and improve high-frequency gain stability

Answer

Double the output voltage swing beyond a single stage

Answer

Lower the noise figure of the amplifier stage

Answer

Reduce the power supply voltage requirement by half