Electronics and Communication Engineering - Communication Systems - Discussion

Coherent detection requires the phase information of the carrier phase. This can be achieved either by sending a carrier from a transmitter or by using a local oscillator at the receiver that is phase locked with the transmitter. Thus there exists a phase difference between the two which has to be estimated and corrected for detection. In non-coherent detection, no phase information is required. Since PM is required to continually change the phase of the carrier, therefore, non-coherent detection which does not require phase information can't be used to detect it. To detect PM one must use phase information as the message is present in phase information.

Non-coherent detection is not possible because at the receiver end the same frequency should be used as that of at the transmitter end, And coherency maintenance is must.

Non-coherent detection process doesn't need receiver to be phase locked with transmitted carrier. As the main objective is phase itself, so how could we determine PSK!

Because amplitude and phase of the carrier is constant.

Non-coherent detection is not possible in PSK and FSK because the receiver needs to know the carrier phase and frequency, respectively, to demodulate the signal accurately.

With respect to phase when we talk, detection is random in nature and mapping of information cannot be done correctly, so we need exact estimation and detection process.

Because in PSK modulation technique the phase of the modulated is changed according to the phase of the baseband signal.

It is not possible because the imprint of the data lies in phase itself.

Phase always indicates the exact position of the signal. So we need exact phase we need synchronous the modulation.

When the receiver exploits knowledge of the carrier's phase to detect the signal. The process is called coherent detection.