Physical layer synchronization algorithms for signal-code sequence increasing noise immunity of dvb-s2x standard vl-snr mode

The work is devoted to expanding the noise immunity of the DVB-S2X standard and the VL-SNR mode physical layer synchronization algorithms. The article proposes a signal-code sequence that increases the noise immunity of the signal, operating down to −11 dB signal-to-noise ratio, and a synchronization system for it.

Study of the Metal Crack Propagation by Acoustic Emission Testing

Crack propagation is the main reason which leads to the invalidity of the metal components. A set of detecting equipment based on the acoustic emission method was designed, and it was mainly composed of acoustic emission sensor, signal operating circuits and signal acquisition system. Specimens of 16MnR material were manufactured and the static axial tension test of them was carried on. Acoustic emission signals from the specimen were detected by acoustic emission equipment by using piezoelectric ceramic sensor. Signal datum were acquired and operated by the acquisition system, as well as the acquisition program written for it. The final results has demonstrated that acoustic emission equipment designed for the test performed well in acquiring the signals induced by the metal crack propagation.