In a circuit for decoding a multiplex signal in a stereo receiver, where the multiplex signal contains a composite signal (L+R) in the base band, a subcarrier modulated with a difference signal (L-R), and a pilot signal with half the frequency of the subcarrier, the multiplex signal in digital form is multiplied (2, 3) by a reference carrier generated with a sampling clock signal (14) produced in the radio receiver, where the reference carrier is present in two phase positions shifted 90.degree. with respect to each other. The mix or product signals resulting from this multiplication are multiplied (4, 5) by one correction signal each, thus forming corrected mix signals. The corrected mix signals are added (6) and supplied to a matrix circuit (8, 9), together with the composite signal, to create respective stereo audio channel signals (L, R).