HAM FREE HAM Radio Extra Class Test Practical Circuits and Components Questions and Answers 2

Question 1

What is the primary advantage of a Chebyshev low-pass filter design compared to a Butterworth design of the same order?

Accepted Answer

Steeper rolloff in the stopband

Answer

Chebyshev filters achieve a steeper transition from passband to stopband than Butterworth filters of the same order, at the cost of passband ripple.

Question 2

In a Class AB push-pull amplifier, what is the purpose of the slight forward bias applied to both transistors?

Accepted Answer

To reduce crossover distortion

Answer

The slight forward bias in Class AB operation keeps both transistors conducting near the zero-crossing point, eliminating the crossover distortion seen in pure Class B designs.

Question 3

What type of circuit is typically used to generate a stable reference frequency from a crystal oscillator for a PLL synthesizer?

Accepted Answer

Temperature-compensated crystal oscillator (TCXO)

Answer

A TCXO provides the highly stable reference frequency needed by PLL synthesizers to maintain accurate output frequencies across temperature variations.

Question 4

What is the function of a diplexer in an amateur radio station?

Accepted Answer

To allow simultaneous operation on two different bands using one antenna

Answer

A diplexer uses frequency-selective filters to route signals of different frequency bands to or from a single antenna without mutual interference.

Question 5

Which component in a superheterodyne receiver is responsible for rejecting the image frequency?

Accepted Answer

The preselector or front-end bandpass filter

Answer

The preselector filter ahead of the mixer attenuates the image frequency, which is separated from the desired signal by twice the IF.

HAM - Radio Extra Class Test Practice Test

HAM - Radio Extra Class Test Practice Test

HAM FREE HAM Radio Extra Class Test Practical Circuits and Components Questions and Answers 2