Moving with unusual speed, the Senate today began the process of reversing the recent decision by federal regulators to loosen media ownership rules and enable the nation's largest newspaper and broadcasting conglomerates to grow even larger.

A broadly bipartisan group of the Senate Commerce Committee approved legislation by voice vote to restore the earlier limits on the number of television stations a network can own. The bill would also restore most of the restrictions that have long prevented a company from owning both a newspaper and a radio station or television station in the same city.

One provision of the bill would go beyond reinstating the previous ownership rules by forcing a number of big radio companies, including Clear Channel Communications, to divest themselves of some of their stations.

The Senate vote was a clear rebuke of Michael K. Powell, the chairman of the Federal Communications Commission, who was the architect of the deregulation.