A method is provided for determining the amplification factors both of a data channel and of a controlled channel of a data transmission system, wherein the data transmission is performed in a normal mode or a compression mode, a nominal ratio is calculated in the normal mode from signaled reference amplification factors, and further amplification factors are determined therefrom via rounding or discretization, and a corrected nominal ratio is calculated from the nominal ratio in the compression mode, and amplification factors are determined therefrom via rounding or discretization.