A radio receiver designed to measure weak signals in the presence of noise; also known as a Dicke receiver. The input to the receiver is rapidly switched (by a Dicke switch) between the antenna and a reference noise source. It is useful where accurate measurements of absolute flux are required, and has been used to measure the very weak signal from the cosmic microwave background. It is named after R. H. Dicke.
Subjects: Astronomy and Astrophysics.