The station's local sales division will remain in Atlantic FM's St Agnes office and will be equipped with new systems and hardware later this year. National sales will be handled by Global Radio's national ad sales team.
The station's breakfast, drivetime and weekend morning shows will be shared with Global Radio's Heart station in Devon and broadcast from its centre in Exeter. There will also be hourly Cornwall-focused news bulletins.
All other programming will be shared with Global Radio's Heart national network.
A spokeswoman for Global Radio said the station was bought from a number of private investors but declined to provide the names of the investors or the value of the deal.
Atlantic FM had an average weekly reach of 71,000 listeners in the final three months of 2011, according to Rajar.
Jeremy Scott, deputy chairman, Atlantic, said: "Very few local stations get the invitation to join a network like Heart, where they care about the localness of their output and offer high quality network programming in a challenging new digital era.
Heart is the biggest commercial network in the country with an average weekly reach of 7.47 million listeners in Q4 2012, according to Rajar, although this was down 3.6% year on year and down 2.4% quarter on quarter.
Ashley Tabor, founder and executive president of Global Group, said: "This is an exciting development for Heart. We've wanted to achieve this for some time and we warmly welcome Cornwall to the Heart family."
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