The San Juan is a German-built, 65-meter long (213-foot) TR-1700 submarine, powered by one electric and four diesel engines.
"Special software is being used to study different sounds and acoustics", navy spokesman Enrique Balbi told reporters in Buenos Aires.
Authorities were investigating white flares spotted in the South Atlantic overnight, as urgency grew on Tuesday in the search for a missing Argentine navy submarine amid worry that its 44 crew members could be running out of oxygen.
As waves of up to 20 feet complicated the search, authorities spent Sunday analyzing data from possible satellite calls that were thought to have been made from the vessel.
But if the sub doesn't surface, oxygen might last only seven days, Balbi said.
More than a dozen global vessels and aircraft have joined the search for the missing submarine, which has been set back by stormy weather that has caused waves up to 20 feet. Authorities have mainly been scanning the sea from the sky, as storms have made it hard for boats. A man walks past a banner in the colours of the Argentine national flag, outside the Argentine Naval Base where the ARA San Juan submarine that is missing at sea sailed from, in Mar del Plata, Argentina November 20, 2017.
Argentina's navy says a noise detected in an undersea area on Monday did not come from a submarine that has been missing since last week with 44 sailors on board.More news: Broncos Paxton Lynch expected to start against Raiders
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"A warship has a lot of backup systems, to allow it to move from one to another when there is a breakdown", he said.
The ARA San Juan was returning from a routine mission to Ushuaia, near the southern-most tip of South America, towards Mar del Plata.
The ARA San Juan was inaugurated in 1983, making it the newest of the three submarines in the Argentine Navy's fleet.
They were joined by President Mauricio Macri: "We continue to deploy all available national and worldwide resources" to find the submarine, he tweeted. Grief counselors, five psychologists and a psychiatrist, are lending their support to the families of the crew members.
Intermittent satellite communications were detected on Saturday and the government had said they were likely to have come from the submarine. "It's dependent upon the last time they actually recharged their batteries, how long ago they refreshed the air, what's inside the submarine", Reed said.
According to local media, the captain of the ARA San Juan contacted the naval base again after reporting the mechanical problem.