A Chinese vessel cruising in the southern Indian Ocean off the west coast of Australia has picked up a pulse signal which has thus far been the closest clue that might lead to the finding of the missing flight MH370 as the signal's frequency ( 37.5 kHz) represents the homing signal that a submerged black box from an aircraft.

To compare the pulse signal, especially its waveform, with the vessel's previous finding -- not strong enough to be recorded -- is now a top priority for the Chinese search team.

As the search enters its 28th day, soon before the black box's battery is expected to die, the discovery has matched speculations by aerial search crews regarding the location of the signal source.

However, aviation experts have noted each aircraft is configured to emit the 37.5 kHz signal with a different waveform, necessary to distinguish one aircraft from another in case an air crash should involve more than one plane.

This is why the waveform of the signal is also referred to as a "unique identity" -- like a person's ID number -- to an aircraft.

The Chinese search vessel is yet to compare its record of the signal's waveform with the Boeing factory's recorded configuration of the missing B-777 (product serial number 9M-MRO) to give out a final confirmation whether or not the signal came from MH370.