What is garbled?

Some articles on garbled:

The Angry Sun - Season 2 - Episodes
... electrical circuits, but the communication system holds out long enough to record a garbled radio message from an unknown source ... When Wildstar asks about the radio message, Sandor plays it back although mostly garbled, it appears to contain a woman's voice ... On the Argo's bridge, the crew receive a garbled message from Telezart, but they are able to at least extract navigational coordinates from the message ...
USS Thresher (SSN-593) - Disaster Sequence
... The transmission is garbled, though some words are recognizable " experiencing minor difficulty, have positive up-angle, attempting to blow." The submarine, growing ... Are you in control?" 0916 Skylark picks up a garbled transmission from Thresher, transcribed in the ship's log as "900 N." 0917 A second transmission is received, with the partially recognizable phrase "e ... Last transmission received was garbled ...