(CNN) -- A Chinese patrol ship searching for signs of Malaysia Airlines Flight 370 in the southern Indian Ocean discovered Saturday the pulse signal used by so-called black boxes, state news agency Xinhua reported.
But the pulse signal has not been confirmed, China's Maritime Search and Rescue Center reported, according to China Communications News, which is the Ministry of Transport's official newspaper.
The signal reported -- 37.5 kHz -- "is the standard beacon frequency" for the plane's cockpit voice recorder and the flight data recorder, said Anish Patel, president of pinger manufacturer Dukane Seacom.
The frequency was chosen for use in the recorders "to give that standout quality that does not get interfered with by the background noise that readily occurs in the ocean."
But he said he would like to see more evidence. "I'd like to see some additional assets on site quickly -- maybe some sonobuoys," he said, referring to 5-inch-long (13-centimeter) sonar systems that are dropped from aircraft or ships.
And he said he was puzzled that only one signal had been detected, since each of the recorders was equipped with a pinger, which is also called a beacon.
Other experts cautioned that no confirmation had been made that the signal was linked to the missing plane.
"We are unable to verify any such information at this point in time," the media office of the Joint Agency Coordination Centre said in an e-mail.
"We've had a lot of red herrings, hyperbole on this whole search," said oceanographer Simon Boxall, a lecturer in ocean and earth science at the University of Southampton told CNN. "I'd really like to see this data confirmed."
If this proves to be what investigators have been searching for, "then the possibility of recovering the plane -- or at least the black boxes -- goes from being one in a million to almost certain," he said.
But, he added, "It could be a false signal."
CNN aviation analyst David Soucie was less skeptical. "This is a pinger," the airplane accident investigator said. "I've been doing this a lot of years, and I can't think of anything else it could be."
Xinhua said the detector deployed by the Haixun (pronounced "high shuen") 01 patrol ship picked up the signal around 25 degrees south latitude and 101 degrees east longitude. "It is yet to be established whether it is related to the missing jet," it said.