Experimental verification of the performance of Direct Spectrum Division Transmission adapter for satellite communications/broadcasting

摘要

NTT Laboratory has been studying a direct spectrum division transmission(DSDT) adapter that can divide a single carrier signal into multiple sub-spectra and assign them to dispersed frequency slots to better utilize the spectrum resources of the satellite transponder. Since the spectrum editing technique is employed to keep the total occupied bandwidth after spectrum division that same as that before spectrum division, the spectrum output by the Rx DSDT adapter has full roll-off characteristics. While theoretically it is not necessary to apply a receiving root roll-off filter to the output of the Rx DSDT adapter, in practice, such a filter is unavoidable. This triggers inter symbol interference (ISI) and Bit Error Rate (BER) performance is degraded. Moreover, the BER performance of spectrum divided signals should be degraded due to the non-linear amplification and the characteristics of analog devices implemented in the adapters. Therefore, it is essential to evaluate this performance degradation quantitatively to confirm the practical application of the DSDT adapter. Experiments were conducted to verify the performance of the DSDT adapter in satellite communications/broadcasting. The results confirm that the performance degradation is less than 0.5dB making the DSDT adapter useful in satellite communications/broadcasting.