Costas loop carrier recovery

1. What is the advantage of Costas loop?
2. What is carrier phase recovery?
3. What type of feedback is used in Costas loop and why?
4. What are the applications of Costas loop?

What is the advantage of Costas loop?

. This translates to double the sensitivity and also makes the Costas loop uniquely suited for tracking Doppler-shifted carriers, especially in OFDM and GPS receivers.

What is carrier phase recovery?

Carrier phase recovery (CPR) is an indispensible function in such coherent receivers, in which the random phase shifts induced by laser phase noise at both transmitter and receiver sides need to be compensated.

What type of feedback is used in Costas loop and why?

Fig 1 -- In the basic phase-locked loop structure the system relies on feedback formed by mixing a reference signal with a received waveform. received signal are equal in phase and frequency they are locked in sync.

What are the applications of Costas loop?

The Costas loop is a classical analog PLL based circuit for carrier recovery[6–8]. Nowadays, among the applications of Costas loop, there are global positioning systems (GPS)[9, 10], wireless communication[11] and others[8, 12–19].