phase locked loop advantages

[dinesh401]

What is the main advantage of phase locked loop ?...If PLL is not implemented in demodulation, what is the disadvantage ?

Why to lock the frequency of oscillator signal with incoming signal in demodulation ? If not locked, what is the problem ?

 

[jiripolivka]

Read some basics before asking, please.
PLL systems are very important in generating accurate and stable frequency, also in synthesizers. A phase or frequency-modulated signal can be well demodulated by a PLL system which recovers a carrier.
Locking characteristic is a very important feature in PLL system.
A PLL oscillator locked to a reference harmonic offers a very low phase noise defined by that reference.

 

[chuckey]

Synchronised demodulation is required for accurate phase demodulation. if the local oscillator becomes "unlocked" then you will have a sinewave sitting on your output signal that is the frequency offset. Some sorts of AM using SSB/VSB, also need synchronous demodulation.
Frank

 

[Jibby Benjamen]

Frequency drift