A Chinese patrol ship looking for signs of Malaysia Airlines Flight 370 in the southern Indian Ocean discovered Saturday a pulse signal with a frequency of 37.5 kHz, state news agency Xinhua reported. “That is the standard beacon frequency” for both so-called black boxes — the cockpit voice recorder and the flight data recorder, said Anish Patel, president of pinger manufacturer Dukane Seacom. “They’re identical.” But 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. More