| タイトル | The Use of Subcarriers in Future DSN Missions |
| 本文（外部サイト） | http://hdl.handle.net/2060/19930009726 |
| 著者（英） | Nguyen, T. M.; Hinedi, S. M.; Shihabi, M. M. |
| 著者所属（英） | Jet Propulsion Lab., California Inst. of Tech. |
| 発行日 | 1992-11-15 |
| 言語 | eng |
| 内容記述 | The performance of deep space telemetry signals that employ a residual carrier modulation technique is compared in the presence and absence of a subcarrier. When the subcarrier is present, the performance for the resulting pulse-coded modulation/phase-shift keyed/phase-modulated (PCM/PSK/PM) scheme is evaluated for both sine wave and square wave subcarriers and non-return-to zero (NRZ) data. When the subcarrier is absent, the performance for the resulting PCM/PM technique is evaluated for both the NRZ and the bi-phase data format. The comparison is based on telemetry performance as well as bandwidth efficiency. The first criterion is characterized in terms of the symbol error rate (SER) as a function of symbol SNR, loop bandwidth-to-data rate ratio, and modulation index. The bandwidth efficiency is characterized by the occupancy factor. The results of both the analysis and measurements show that when the interference-to-carrier ratio (ICR) is less than -15 dB, the performance degradation in the absence of a subcarrier is negligible. Various combinations of loop bandwidth-to-data rate ratios and modulation indices that achieve this performance are derived and listed. Bandwidth occupancy comparison indicates that PCM/PM/NRZ is the most efficient in this regard. Therefore, by eliminating the subcarrier and using the PCM/PM/NRZ scheme, many advantages can be realized without any sacrifice in performance. |
| NASA分類 | COMMUNICATIONS AND RADAR |
| レポートNO | 93N18915 |
| 権利 | No Copyright |
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