PLL DEMODULATION TECHNIQUE FOR M-RAY POSITION PHASE SHIFT KEYING

The paper presents a kind of transmission system which employs M-ary Position Phase Shift Keying(MPPSK) to send data and Phase Locked Loop(PLL) based techniques for data retrieve.With a single PLL, MPPSK demodulation is achieved, as well as carrier recovery and symbol synchronization.Firstly, MPPSK modulation method is briefly introduced.2PPSK's PSD expression is given with its optimization result.Orthogonal Phase Detector(PD) and static threshold are used for the purpose of wider phase range and simplicity in demodulation.The data rate is alterable, which is 4.65 kbps for 2PPSK and 9.3 kbps for 4PPSK in the paper.Then some indicative comparisons in Signal to Noise Ratio Symbol Error Rate(SNR-SER) are made among 2PPSK, 3PPSK and 4PPSK, of which 4PPSK has proved to be optimal in ten slots each symbol conditions.And finally, it is demonstrated by system simulations that lower than 10-4 Symbol Error Rate(SER) performance can be obtained at 13 dB symbol SNR.

Humidity-Induced Spectral Shift in a Cross-DispersionEchelle Spectrometer and Its Theoretical Investigation

The relationship between ambient relative humidity H and the position shift of a spectral line was investigated both experimentally and theoretically.An echelle-based ICP emission spectrometer equipped with a CID detector was used for experimental verification of the derived model.The shift of a spectral line is quantitatively described by two defined spectral shift functions: Δλx(x,λ,H)(in the x direction of the CID detector) and Δλy(y,λ,H)(in the y direction of the CID detector).Experimental results indicate that Δλx(x,λ,H) does not change with a variation in ambient relative humidity, but Δλy(y,λ,H) does.A spectral shift equation,i.e.an empirical second-order polynomial equation,can be used to describe the relationship between Δλy(y,λ,H) and H.Based on the classical dipole model,classical mechanics and electrodynamics the empirical spectral-shift equation involving Δλy(y,λ,H) and H was theoretically deduced.The theoretical result is in good agreement with the experimental findings.The theoretical results indicate that the coefficients of the empirical spectral-shift equation are related to the basic physical parameters of materials and the geometric configuration of the echelle CID ICP-AES,and also provide physical meaning to the coefficients of the empirical shift equation obtained experimentally.

Convenient Synthesis of Indene Derivatives via Intramolecular Friedel-Crafts Cyclization of Tetraaryl Substituted 1,3-Butadienes

A convenient and efficient method for the highly regioselecfive synthesis of indene derivatives 4 and 5 from tetraaryl substituted 1,3-butadienes 3 was described. The method involves an intramolecular Friedel-Crafts cyclization and a corresponding double-bond positional shift of isomers 4 and 5 in the presence of different Lewis acids under mild conditions with higher than 90% yields.

Modulation of the effective work function of TiN metal gate for PMOS application

It is important to find a way to modulate the work function of TiN metal gate towards the valence band edge of Si,which can meet the lower threshold voltage requirement of p-type metal-oxide-semiconductor（MOS） transistor.In this work,effects of TiN thickness,post-deposition annealing（PDA）,oxygen incorporation and N concentration variation on the work function of TiN metal gate in MOS structures are systematically investigated. It can be found that the work function positively shifts at the initial stage as the thickness of the TiN layer increases and stabilizes at such a thickness.PDA at N_2 ambience with a trace of O_2 can also cause a positive shift in the work function of TiN metal gate.The same tendency can be observed when oxygen is incorporated into TiN.Finally, increasing the N concentration in TiN can also positively shift the work function.All these measures are effective in modulating the TiN metal gate so that it is more suitable for PMOS application.