(D)Element 3-31

Question 1

What frequency synthesizer circuit used a phase comparator, look-up table, digital to analog converter, and a low-pass antialias filter?

Answer 1

a direct digital synthesizer

Question 2

A circuit that compares the output of a voltage-controlled oscillator to a frequency standard and produces an error voltage that is then used to adjust the capacitance of a varactor diode used to control frequency in that same VCO is called what?

Answer 2

phase-locked loop

Question 3

RF input to a mixer is 200 MHz and the local oscillator frequency is 150 MHz. What output would you expect to see at the IF output prior to any filtering?

Answer 3

50,150,200, 350

Question 4

What spectral Impurity components might be generated by a phase-locked-loop-synthesizer?

Answer 4

broadband noise

Question 5

In a direct digital synthesizer, what are the unwanted components on its output?

Answer 5

spurs at discrete frequencies

Question 6

What is the definition of a phase-locked-loop circuit?

Answer 6

a servo loop consisting of a phase detector, a low pass filter, and voltage-controlled oscillator