Explanation: The output voltage of a phase detector is a dc voltage and is often referred to as error voltage. This output is applied to the low pass filter which removes the high frequency noise and produces a dc level. 6. What is the need to generate corrective control voltage?
A. To maintain the lock
B. To track the frequency change
C. To shift the VCO frequency
D. All of the mentioned
Answer:A
Explanation: The output voltage of a phase detector is a dc voltage and is often referred to as error voltage. This output is applied to the low pass filter which removes the high frequency noise and produces a dc level. 6. What is the need to generate corrective control voltage?
A. To maintain the lock B. To track the frequency change C. To shift the VCO frequency D. All of the mentioned
Explanation: The output frequency(fo) of VCO is identical to input frequency(fs) except for a finite phase difference(φ), which generates a corrective control voltage to shift VCO frequency from fo to fs, thereby maintains the lock once locked and PLL tracks the frequency changes of the input signal. 7. At what range the PLL can maintain the lock in the circuit?