This paper adopts the spectrum averaging method to analyze the effects of clock jitter and the additive white noise to the noise floor of ADC blocks,and derives the noise floor formula,which is validated by computer simulation.

Effects of rolloff factor on resistance to time delay spread and spectral efficiency of adaptive QAM;

Asymptotic spectral efficiency of the multicarrier code division multiple access;

Improvement in spectral efficiency of multiwavelength optical CDMA network;

Study of spectrum efficiency in the third generation communication system;

Higher order harmonic components are reduced for spectrum efficiency improvement,with optimized waveform expressions.

,diamond sector and pentagonal sector) to improve the spectrum efficiency in the future OFDM-based mobile cellular system,particularly in the case of the uneven distribution of the traffic among cells/sectors.

Resource allocation algorithm to improve frequency efficiency of low SNR OFDM systems

And the frequency efficiency of TD-SCDMA is very high.

Limited frequency resource becomes the leading factor to the improvement of system performance along with the development of mobile telecommunication, and how to improve the frequency efficiency is one of the pop topic in researching area.

Simulation and mean frequency estimation on ultrasound seawater flow signals;

Several mean frequency estimation methods for Doppler ultrasound signals have been introduced in this paper,then a new mean frequency estimation method based on Teager algorithm is proposed.

<Abstrcat>From molecular beam s speed distribution function,molecular beam s frequency distribution function is deduced,and calculates mean frequency,root-mean-square frequency and most possible frequency are calculated,and compared with corresponding characteristic quantities of speed distribution function one by one,and their physical significance are explaned.