| 摘要 |
<p>The invention relates to a modulation method, especially an optical modulation method, using the principle of discrete IQ modulation comprising the steps of: generating a carrier signal (S c ) and splitting the carrier signal at a splitting position (25) in an I branch signal and a Q branch signal, the I branch and Q branch being provided between the splitting position (25) and a combining position (27); modulating the amplitude of the I branch signal according to a first modulation signal and modulating the amplitude of the Q branch signal according to a second modulation signal, each of the first and second modulation signals being arranged to adopt a given number of values according to a given number of constellation points of a given modulation scheme; phase shifting the signal in the Q branch versus the signal in the I branch by a predetermined value; and combining the signals in the I branch and Q branch at the combining position, the combined modulated signal (S tx,mod ) being arranged to be transmitted over a transmission path; wherein the phase of the signal in the Q branch is phase shifted versus the signal in the I branch by a value unequal to 90 degrees.</p> |
