Which of the following statement best describe the role of a “deflator”?

A deflator is a value that allows data to be measured over time in terms of some base period, usually through a price index, in order to distinguish between changes in the money value of a gross national product (GNP) that come from a change in prices, and changes from a change in physical output. The GDP deflator , also called implicit price deflator , is a measure of inflation. It is the ratio of the value of goods and services an economy produces in a particular year at current prices to that of prices that prevailed during the base year.