Patent ID: 8249459

Claim:
A method of generating time-division multiplexed encoded transmission signals, comprising: encoding optical pulse signals for each of a plurality of multiplexed channels whose bit rate is F bit/s and generating a transmission signal for each channel; performing time division multiplexing on first and second transmission signals selected from the transmission signals of the plurality of multiplexed channels and generating a 2-channel multiplexed signal; modulating the multiplexed signal with a modulation signal having a frequency of (F−Δf) Hz, where Δf is defined as a real number satisfying the condition Δf>0 and F is defined as a real number satisfying the condition F>Δf; detecting a strength of a Δf Hz frequency component of the multiplexed signal modulated by the modulation signal; changing a time delay amount of the second transmission signal with respect to the first transmission signal, and determining a time delay amount at which a strength of the Δf Hz frequency component is minimized; and applying a time delay to the transmission signal of each of the multiplexed channels on the basis of the determined time delay amount, and adjusting the transmission signals of the individual channels such that they are arranged at equidistant intervals on a time axis.