Citation
Abstract
Computer simulated noise performance of the symbol synchronizer loop (SSL) in the Block V receiver is compared with the theoretical noise performance. Good agreement is seen at the higher loop SNR’s (SNRx’s), with gradual degradation as the SNR, is decreased. For the different cases simulated, cycle slipping is observed (within the simulation time of 107 seconds) at SNR,,’s below different thresholds, ranging from 6 to 8.5 dB, comparable to that of a classical phase-locked loop. An important point, however, is that to achieve the desired loop SNR above the seemingly low threshold to avoid cycle slipping, a large data-to-loop-noise power ratio, Pp/(NoBL), is necessary (at least 13 dB larger than the desired SNRxz in the optimum case and larger otherwise). This is due to the large squaring loss (> 13 dB) inherent in the SSL. For the special case of symbol rates approximately equaling the loop update rate, a more accurate equivalent model accounting for an extra loop update period delay (characteristic of the SSL phase detector design) is derived. This model results in a more accurate estimation of the noise-equivalent bandwidth of the loop.
Details
- Volume
- 42-111
- Published
- November 15, 1992
- Pages
- 179–191
- File Size
- 501.1 KB