symbol rate
4.To realize high-speed satellite communication, a scheme of design and implementation of high-speed demodulator for π/4QPSK signal is put forward based on FPGA and ASIC The intermediate frequency (IF) of π/4QPSK signal is 140MHz and symbol rate is 2M～45Mbaud The major parts of demodulator: I-Q demodulation, carrier recovery and timing recovery are discussed in detail, including the selection of devices and the implementation of corresponding algorithms
6.The simulation results show that if smart antenna is utilized to suppress multipath and the synchronization error between users is limited in 3/8 chip period, the symbol error rate (SER) performance approaches single user bound (SUB) and spectral efficiency amounts to 4bit/s/Hz, after the proposed scheme is applied.
7.As special Multi-Carrier Modulation (MCM) technology, Orthogonal Frequency Division Multiplexing (OFDM) is quite competitive in the field of integrated wireless access. It has many strengths, such as the strong ability to resist Inter symbol Interference (ISI), the high rate of spectrum usage efficiency.
8.In comparison to single-carrier transmission, Orthogonal frequency division multiplexing (OFDM) is quite effective to eliminate inter-symbol interference (ISI) caused by channel multipath fading hostility, while providing high transmission data rate with high spectral efficiency.
9.After analyzing the symbol structure of pulse position modulation (PPM), digital pulse interval modulation (DPM) and dual-header pulse interval modulation(DH-PIM) in detail, the average transmission power and bandwidth efficiency are analyzed. On the meantime, the slot error rate is also analyzed on the given model.
10.The resting heart rate of the boxers is(48.24±9.06) beat/min,it is significantly lower than the controlling group(P<0.005),and there is equality in the incidence of sinus arrhythmia between the groups. These show that there is the enormous adaptogenesis of cardiac-vessel function in the boxers and these changes are the good performance of cardiac reserve and the symbol increased exercise capacity.
