| 摘要 |
A method of SSB OFDM data transmission over optical fibre. A dual Mach-Zehnder modulator (142) is driven by two drive signals (132, 134). The drive signals are generated by parallel processing arms (200a, 200b) by baseband digital processing. From input data, N-QAM symbols are derived and input to each processing arm. In one of the arms the N-QAM symbols are phase shifted by 90 degrees (1320) before the OFDM processing chain. Subsequent IFFT processing (1324) then causes the correct phasing of the OFDM sidebands to arise, obviating the need for wideband FIR or IIR filters to implement a Hilbert transform. |
